注塑成型的模具设计外文翻译
塑料注塑模具中英文对照外文翻译文献
外文翻译及原文(文档含英文原文和中文翻译)【原文一】CONCURRENT DESIGN OF PLASTICS INJECTION MOULDS AbstractThe plastic product manufacturing industry has been growing rapidly in recent years. One of the most popular processes for making plastic parts is injection moulding. The design of injection mould is critically important to product quality and efficient product processing.Mould-making companies, who wish to maintain the competitive edge, desire to shorten both design and manufacturing leading times of the by applying a systematic mould design process. The mould industry is an important support industry during the product development process, serving as an important link between the product designer and manufacturer. Product development has changed from the traditional serial process of design, followed by manufacture, to a more organized concurrent process where design and manufacture are considered at a very early stage of design. The concept of concurrent engineering (CE) is no longer new and yet it is still applicable and relevant in today’s manuf acturing environment. Team working spirit, management involvement, total design process and integration of IT tools are still the essence of CE. The application of The CE process to the design of an injection process involves the simultaneous consideration of plastic part design, mould design and injection moulding machine selection, production scheduling and cost as early as possible in the design stage.This paper presents the basic structure of an injection mould design. The basis of this system arises from an analysis of the injection mould design process for mould design companies. This injection mould design system covers both the mould design process and mould knowledge management. Finally the principle of concurrent engineering process is outlined and then its principle is applied to the design of a plastic injection mould.Keywords :Plastic injection mould design, Concurrent engineering, Computer aided engineering, Moulding conditions, Plastic injection moulding, Flow simulation1.IntroductionInjection moulds are always expensive to make, unfortunately without a mould it can not be possible ho have a moulded product. Every mould maker has his/her own approach to design a mould and there are many different ways of designing and building a mould. Surely one of the most critical parameters to be considered in the design stage of the mould is the number of cavities, methods of injection, types of runners, methods of gating, methods of ejection, capacity and features of the injection moulding machines. Mould cost, mould quality and cost of mould product are inseparableIn today’s completive environment, computer aided mould filling simulation packages can accurately predict the fill patterns of any part. This allows for quick simulations of gate placements and helps finding the optimal location. Engineers can perform moulding trials on the computer before the part design is completed. Process engineers can systematically predict a design and process window, and can obtain information about the cumulative effect of the process variables that influence part performance, cost, and appearance.2.Injection MouldingInjection moulding is one of the most effective ways to bring out the best in plastics. It is universally used to make complex, finished parts, often in a single step, economically, precisely and with little waste. Mass production of plastic parts mostly utilizes moulds. The manufacturing process and involving moulds must be designed after passing through the appearance evaluation and the structure optimization of the product design. Designers face a hugenumber of options when they create injection-moulded components. Concurrent engineering requires an engineer to consider the manufacturing process of the designed product in the development phase. A good design of the product is unable to go to the market if its manufacturing process is impossible or too expensive. Integration of process simulation, rapid prototyping and manufacturing can reduce the risk associated with moving from CAD to CAM and further enhance the validity of the product development.3. Importance of Computer Aided Injection Mould DesignThe injection moulding design task can be highly complex. Computer Aided Engineering (CAE) analysis tools provide enormous advantages of enabling design engineers to consider virtually and part, mould and injection parameters without the real use of any manufacturing and time. The possibility of trying alternative designs or concepts on the computer screen gives the engineers the opportunity to eliminate potential problems before beginning the real production. Moreover, in virtual environment, designers can quickly and easily asses the sensitivity of specific moulding parameters on the quality and manufacturability of the final product. All theseCAE tools enable all these analysis to be completed in a meter of days or even hours, rather than weeks or months needed for the real experimental trial and error cycles. As CAE is used in the early design of part, mould and moulding parameters, the cost savings are substantial not only because of best functioning part and time savings but also the shortens the time needed to launch the product to the market.The need to meet set tolerances of plastic part ties in to all aspects of the moulding process, including part size and shape, resin chemical structure, the fillers used, mould cavity layout, gating, mould cooling and the release mechanisms used. Given this complexity, designers often use computer design tools, such as finite element analysis (FEA) and mould filling analysis (MFA), to reduce development time and cost. FEA determines strain, stress and deflection in a part by dividing the structure into small elements where these parameters can be well defined. MFA evaluates gate position and size to optimize resin flow. It also defines placement of weld lines, areas of excessive stress, and how wall and rib thickness affect flow. Other finite element design tools include mould cooling analysis for temperature distribution, and cycle time and shrinkage analysis for dimensional control and prediction of frozen stress and warpage.The CAE analysis of compression moulded parts is shown in Figure 1. The analysis cycle starts with the creation of a CAD model and a finite element mesh of the mould cavity. After the injection conditions are specified, mould filling, fiber orientation, curing and thermal history, shrinkage and warpage can be simulated. The material properties calculated by the simulation can be used to model the structural behaviour of the part. If required, part design, gate location and processing conditions can be modified in the computer until an acceptable part is obtained. After the analysis is finished an optimized part can be produced with reduced weldline (known also knitline), optimized strength, controlled temperatures and curing, minimized shrinkage and warpage.Machining of the moulds was formerly done manually, with a toolmaker checking each cut. This process became more automated with the growth and widespread use of computer numerically controlled or CNC machining centres. Setup time has also been significantly reduced through the use of special software capable of generating cutter paths directly from a CAD data file. Spindle speeds as high as 100,000 rpm provide further advances in high speed machining. Cutting materials have demonstrated phenomenal performance without the use of any cutting/coolant fluid whatsoever. As a result, the process of machining complex cores and cavities has been accelerated. It is good news that the time it takes to generate a mould is constantly being reduced. The bad news, on the other hand, is that even with all these advances, designing and manufacturing of the mould can still take a long time and can be extremely expensive.Figure 1 CAE analysis of injection moulded partsMany company executives now realize how vital it is to deploy new products to market rapidly. New products are the key to corporate prosperity. They drive corporate revenues, market shares, bottom lines and share prices. A company able to launch good quality products with reasonable prices ahead of their competition not only realizes 100% of the market before rival products arrive but also tends to maintain a dominant position for a few years even after competitive products have finally been announced (Smith, 1991). For most products, these two advantages are dramatic. Rapid product development is now a key aspect of competitive success. Figure 2 shows that only 3–7% of the product mix from the average industrial or electronics company is less than 5 years old. For companies in the top quartile, the number increases to 15–25%. For world-class firms, it is 60–80% (Thompson, 1996). The best companies continuously develop new products. AtHewlett-Packard, over 80% of the profits result from products less than 2 years old! (Neel, 1997)Figure 2. Importance of new product (Jacobs, 2000)With the advances in computer technology and artificial intelligence, efforts have been directed to reduce the cost and lead time in the design and manufacture of an injection mould. Injection mould design has been the main area of interest since it is a complex process involving several sub-designs related to various components of the mould, each requiring expert knowledge and experience. Lee et. al. (1997) proposed a systematic methodology and knowledge base for injection mould design in a concurrent engineering environment.4.Concurrent Engineering in Mould DesignConcurrent Engineering (CE) is a systematic approach to integrated product development process. It represents team values of co-operation, trust and sharing in such a manner that decision making is by consensus, involving all per spectives in parallel, from the very beginning of the productlife-cycle (Evans, 1998). Essentially, CE provides a collaborative, co-operative, collective and simultaneous engineering working environment. A concurrent engineering approach is based on five key elements:1. process2. multidisciplinary team3. integrated design model4. facility5. software infrastructureFigure 3 Methodologies in plastic injection mould design, a) Serial engineering b) Concurrent engineeringIn the plastics and mould industry, CE is very important due to the high cost tooling and long lead times. Typically, CE is utilized by manufacturing prototype tooling early in the design phase to analyze and adjust the design. Production tooling is manufactured as the final step. The manufacturing process and involving moulds must be designed after passing through the appearance evaluation and the structure optimization of the product design. CE requires an engineer to consider the manufacturing process of the designed product in the development phase.A good design of the product is unable to go to the market if its manufacturing process is impossible. Integration of process simulation and rapid prototyping and manufacturing can reduce the risk associated with moving from CAD to CAM and further enhance the validity of the product development.For years, designers have been restricted in what they can produce as they generally have todesign for manufacture (DFM) – that is, adjust their design intent to enable the component (or assembly) to be manufactured using a particular process or processes. In addition, if a mould is used to produce an item, there are therefore automatically inherent restrictions to the design imposed at the very beginning. Taking injection moulding as an example, in order to process a component successfully, at a minimum, the following design elements need to be taken into account:1. . geometry;. draft angles,. Non re-entrants shapes,. near constant wall thickness,. complexity,. split line location, and. surface finish,2. material choice;3. rationalisation of components (reducing assemblies);4. cost.In injection moulding, the manufacture of the mould to produce the injection-moulded components is usually the longest part of the product development process. When utilising rapid modelling, the CAD takes the longer time and therefore becomes the bottleneck.The process design and injection moulding of plastics involves rather complicated and time consuming activities including part design, mould design, injection moulding machine selection, production scheduling, tooling and cost estimation. Traditionally all these activities are done by part designers and mould making personnel in a sequential manner after completing injection moulded plastic part design. Obviously these sequential stages could lead to long product development time. However with the implementation of concurrent engineering process in the all parameters effecting product design, mould design, machine selection, production scheduling,tooling and processing cost are considered as early as possible in the design of the plastic part. When used effectively, CAE methods provide enormous cost and time savings for the part design and manufacturing. These tools allow engineers to virtually test how the part will be processed and how it performs during its normal operating life. The material supplier, designer, moulder and manufacturer should apply these tools concurrently early in the design stage of the plastic parts in order to exploit the cost benefit of CAE. CAE makes it possible to replace traditional, sequential decision-making procedures with a concurrent design process, in which all parties can interact and share information, Figure 3. For plastic injection moulding, CAE and related design data provide an integrated environment that facilitates concurrent engineering for the design and manufacture of the part and mould, as well as material selection and simulation of optimal process control parameters.Qualitative expense comparison associated with the part design changes is shown in Figure 4 , showing the fact that when design changes are done at an early stages on the computer screen, the cost associated with is an order of 10.000 times lower than that if the part is in production. These modifications in plastic parts could arise fr om mould modifications, such as gate location, thickness changes, production delays, quality costs, machine setup times, or design change in plastic parts.Figure 4 Cost of design changes during part product development cycle (Rios et.al, 2001)At the early design stage, part designers and moulders have to finalise part design based on their experiences with similar parts. However as the parts become more complex, it gets rather difficult to predict processing and part performance without the use of CAE tools. Thus for even relatively complex parts, the use of CAE tools to prevent the late and expensive design changesand problems that can arise during and after injection. For the successful implementation of concurrent engineering, there must be buy-in from everyone involved.5.Case StudyFigure 5 shows the initial CAD design of plastics part used for the sprinkler irrigation hydrant leg. One of the essential features of the part is that the part has to remain flat after injection; any warping during the injection causes operating problems.Another important feature the plastic part has to have is a high bending stiffness. A number of feeders in different orientation were added to the part as shown in Figure 5b. These feeders should be designed in a way that it has to contribute the weight of the part as minimum aspossible.Before the design of the mould, the flow analysis of the plastic part was carried out with Moldflow software to enable the selection of the best gate location Figure 6a. The figure indicates that the best point for the gate location is the middle feeder at the centre of the part. As the distortion and warpage of the part after injection was vital from the functionality point of view and it has to be kept at a minimum level, the same software was also utilised to yiled the warpage analysis. Figure 5 b shows the results implying the fact that the warpage well after injection remains within the predefined dimensional tolerances.6. ConclusionsIn the plastic injection moulding, the CAD model of the plastic part obtained from commercial 3D programs could be used for the part performance and injection process analyses. With the aid ofCEA technology and the use of concurrent engineering methodology, not only the injection mould can be designed and manufactured in a very short of period of time with a minimised cost but also all potential problems which may arise from part design, mould design and processing parameters could be eliminated at the very beginning of the mould design. These two tools help part designers and mould makers to develop a good product with a better delivery and faster tooling with less time and money.References1. Smith P, Reinertsen D, The time-to-market race, In: Developing Products in Half the Time. New York, Van Nostrand Reinhold, pp. 3–13, 19912.Thompson J, The total product development organization. Proceedings of the SecondAsia–Pacific Rapid Product Development Conference, Brisbane, 19963.Neel R, Don’t stop after the prototype, Seventh International Conference on Rapid Prototyping, San Francisco, 19974.Jacobs PF, “Chapter 3: Rapid Product Development” in Rapid Tooling: Technologies and Industrial Applications , Ed. Peter D. Hilton; Paul F. Jacobs, Marcel Decker, 20005.Lee R-S, Chen, Y-M, and Lee, C-Z, “Development of a concurrent mould design system: a knowledge based approach”, Computer Integrated Manufacturing Systems, 10(4), 287-307, 19976.Evans B., “Simultaneous Engineering”, Mechanical Engi neering , V ol.110, No.2, pp.38-39, 19987.Rios A, Gramann, PJ and Davis B, “Computer Aided Engineering in Compression Molding”, Composites Fabricators Association Annual Conference , Tampa Bay, 2001【译文一】塑料注塑模具并行设计塑料制品制造业近年迅速成长。
塑料模具注射成型中英文翻译、外文翻译、外文文献翻译
外文翻译原文:Injection MoldingMany different processes are used to transform plastic granules, powders, and liquids into product. The plastic material is in moldable form, and is adaptable to various forming methods. In most cases thermosetting materials require other methods of forming. This is recognized by the fact that thermoplastics are usually heated to a soft state and then reshaped before cooling. Theromosets, on the other hand have not yet been polymerized before processing, and the chemical reaction takes place during the process, usually through heat, a catalyst, or pressure. It is important to remember this concept while studying the plastics manufacturing processes and polymers used.Injection molding is by far the most widely used process of forming thermoplastic materials. It is also one of the oldest. Currently injection molding accounts for 30% of all plastics resin consumption. Since raw material can be converted by a single procedure, injection molding is suitable for mass production of plastics articles and automated one-step production of complex geometries. In most cases, finishing is not necessary. Typical products include toys, automotive parts, household articles, and consumer electronics goods.Since injection molding has a number of interdependent variables, it is a process of considerable complexity. The success of the injection molding operation is dependent not only in the proper setup of the machine hydraulics, barrel temperature variations, and changes in material viscosity. Increasing shot-to-shot repeatability of machine variables helps produce parts with tighter tolerance, lowers the level of rejects, and increases product quality (i.e., appearance and serviceability).The principal objective of any molding operation is the manufacture of products: to a specific quality level, in the shortest time, and using repeatable and fully automaticcycle. Molders strive to reduce or eliminate rejected parts in molding production. For injection molding of high precision optical parts, or parts with a high added value such as appliance cases, the payoff of reduced rejects is high.A typical injection molding cycle or sequence consists of five phases;1. Injection or mold filling2. Packing or compression3. Holding4. Cooling5. Part ejectionPlastic granules are fed into the hopper and through an in the injection cylinder where they are carried forward by the rotating screw. The rotation of the screw forces the granules under high pressure against the heated walls of the cylinder causing them to melt. As the pressure building up, the rotating screw is forced backward until enough plastic has accumulated to make the shot. The injection ram (or screw) forces molten plastic from the barrel, through the nozzle, sprue and runner system, and finally into the mold cavities. During injection, the mold cavity is filled volumetrically. When the plastic contacts the cold mold surfaces, it solidifies (freezes) rapidly to produce the skin layer. Since the core remains in the molten state, plastic follows through the core to complete mold filling. Typically, the cavity is filled to 95%~98% during injection. Then the molding process is switched over to the packing phase.Even as the cavity is filled, the molten plastic begins to cool. Since the cooling plastic contracts or shrinks, it gives rise to defects such as sink marks, voids, and dimensional instabilities. To compensate for shrinkage, addition plastic is forced into the cavity. Once the cavity is packed, pressure applied to the melt prevents molten plastic inside the cavity from back flowing out through the gate. The pressure must be applied until the gate solidifies. The process can be divided into two steps (packing and holding) or may be encompassed in one step(holding or second stage). During packing, melt forced into the cavity by the packing pressure compensates for shrinkage. With holding, the pressure merely prevents back flow of the polymer malt.After the holding stage is completed, the cooling phase starts. During, the part is held in the mold for specified period. The duration of the cooling phase depends primarily on the material properties and the part thickness. Typically, the part temperature must cool below the material’s ejection temperature. While cooling the part, the machine plasticates melt for the next cycle.The polymer is subjected to shearing action as well as the condition of the energy from the heater bands. Once the short is made, plastication ceases. This should occur immediately before the end of the cooling phase. Then the mold opens and the part is ejected.When polymers are fabricated into useful articles they are referred to as plastics, rubbers, and fibers. Some polymers, for example, cotton and wool, occur naturally, but the great majority of commercial products are synthetic in origin. A list of the names of the better known materials would include Bakelite, Dacron, Nylon, Celanese, Orlon, and Styron.Previous to 1930 the use of synthetic polymers was not widespread. However, they should not be classified as new materials for many of them were known in the latter half of the nineteenth century. The failure to develop them during this period was due, in part, to a lack of understanding of their properties, in particular, the problem of the structure of polymers was the subject of much fruitless controversy.Two events of the twentieth century catapulted polymers into a position of worldwide importance. The first of these was the successful commercial production of the plastic now known as Bakelite. Its industrial usefulness was demonstrated in1912 and in the next succeeding years. Today Bakelite is high on the list of important synthetic products. Before 1912 materials made from cellulose were available, but their manufacture never provided the incentive for new work in the polymer field such as occurred after the advent of Bakelite. The second event was concerned with fundamental studies of the nature polymers by Staudinger in Europe and by Carohers, who worked with the Du Pont company in Delaware. A greater part of the studies were made during the 1920’s. Staudinger’s work was primarily fundamental. Carother’s achievements led to the development of our present huge plastics industry by causing an awakening of interest in polymer chemistry, an interest which is still strongly apparent today.The Nature of ThermodynamicsThermodynamics is one of the most important areas of engineering science used to explain how most things work, why some things do not the way that they were intended, and why others things just cannot possibly work at all. It is a key part of the science engineers use to design automotive engines, heat pumps, rocket motors, power stations, gas turbines, air conditioners, super-conducting transmission lines, solar heating systems, etc.Thermodynamics centers about the notions of energy, the idea that energy is conserved is the first low of thermodynamics. It is starting point for the science of thermodynamics is entropy; entropy provides a means for determining if a process is possible.This idea is the basis for the second low of thermodynamics. It also provides the basis for an engineering analysis in which one calculates the maximum amount of useful that can be obtained from a given energy source, or the minimum amount of power input required to do a certain task.A clear understanding of the ideas of entropy is essential for one who needs to use thermodynamics in engineering analysis. Scientists are interested in using thermodynamics to predict and relate the properties of matter; engineers are interested in using this data, together with the basic ideas of energy conservation and entropy production, to analyze the behavior of complex technological systems.There is an example of the sort of system of interest to engineers, a large central power stations. In this particular plant the energy source is petroleum in one of several forms, or sometimes natural gas, and the plant is to convert as much of this energy as possible to electric energy and to send this energy down the transmission line.Simply expressed, the plant does this by boiling water and using the steam to turn a turbine which turns an electric generator.The simplest such power plants are able to convert only about 25 percent of the fuel energy to electric energy. But this particular plant converts approximately 40 percent;it has been ingeniously designed through careful application of the basic principles of thermodynamics to the hundreds of components in the system.The design engineers who made these calculations used data on the properties of steam developed by physical chemists who in turn used experimental measurements in concert with thermodynamics theory to develop the property data.Plants presently being studied could convert as much as 55 percent of the fuel energy to electric energy, if they indeed perform as predicted by thermodynamics analysis.The rule that the spontaneous flow of heat is always from hotter to cooler objects is a new physical idea. There is noting in the energy conservation principle or in any other law of nature that specifies for us the direction of heat flow. If energy were to flow spontaneously from a block of ice to a surrounding volume of water, this could occur in complete accord with energy conservation. But such a process never happens. This idea is the substance of the second law of thermodynamics.Clear, a refrigerator, which is a physical system used in kitchen refrigerators, freezers, and air-conditioning units must obey not only the first law (energy conservation) but the second law as well.To see why the second law is not violated by a refrigerator, we must be careful in our statement of law. The second law of thermodynamics says, in effect, that heat never flows spontaneously from a cooler to a hotter object.Or, alternatively, heat can flow from a cooler to a hotter object only as a result of work done by an external agency. We now see the distinction between an everyday spontaneous process, such as the flow of heat from the inside to the outside of a refrigerator.In the water-ice system, the exchange of energy takes place spontaneously and the flow of heat always proceeds from the water to the ice. The water gives up energy and becomes cooler while the ice receives energy and melts.In a refrigerator, on the other hand, the exchange of energy is not spontaneous. Work provided by an external agency is necessary to reverse the natural flow of heat and cool the interior at the expense of further heating the warmer surroundings.译文:塑料注射成型许多不同的加工过程习惯于把塑料颗粒、粉末和液体转化成最终产品。
模具 塑料注射成型 外文翻译 外文文献 英文文献
模具塑料注射成型外文翻译外文文献英文文献XXXThere are many different processing methods used to convert plastic pellets。
powders。
and liquids into final products。
Plastic materials XXX。
thermoplastic materials XXX。
XXX require other methods。
It is XXX.XXX。
It is also the oldest method。
Suddenly。
XXX account for 30% of all XXX suitable for mass n。
when raw materials XXX in a single step of n。
In most cases。
n machiningis not required for such products。
The us products produced include toys。
automotive parts。
household items。
and electronic consumer goods.Because plastic n molds have many variable nships。
it is a complex and us processing process。
The success of XXX appropriate steps。
but on the XXX。
which leads to the n of XXX。
barrel temperature changes。
XXX ns can help ce tolerances。
ce defect rates。
and increase product quality.XXX operator is to produce products that e first-rate products in the shortest time。
注塑成型及注塑模具专业英语
冲锻 摇动锻造 回转锻造
press forging rocking die forging
rotary forging
压缩成形
compression molding
离心成形
rotational molding
浸渍成形
dip mold
橡胶成形
rubber molding
成型缺陷汉英对照
incrustation
压痕
indentation
internal porosity
偏模
mismatch
mottle nick
overflow
缩颈
橘皮状表面 缺陷
剥离
necking orange peel
peeling
pit
点状腐蚀
pitting corrosion
plate mark
破孔 侧壁皱纹
膜泡 毛边 气泡 细裂痕 修整表面 缺陷 塌陷 腐蚀
成型缺陷汉英对照
low hole
泛白
body wrinkle
冒口带肉
bubble
糊斑
burr cell check
翘曲
表面中部波 皱
龟裂
chipping
铸件凹痕
collapse
色斑
corrosion
裂痕
blushing breaking-in
粉末成形
powder forming
压延成形
calendaring molding
粉末锻造
powder metal forging
冷式压铸 cold chamber die casting
精密锻造
注塑模具设计与制造外文文献翻译
2 Injection molding machineFrom Plastics Wiki, free encyclopediaInjection molding machines consist of two basic parts, an injection unit and a clamping unit. Injection molding machines differ in both injection unit and clamping unit. The name of the injection molding machine is generally based on the type of injection unit used.2.1Types of injection molding machinesMachines are classified primarily by the type of driving systems they use: hydraulic, electric, or hybrid.2.1.1HydraulicHydraulic presses have historically been the only option available to molders until Nissei Plastic Industrial Co., LTD introduced the first all-electric injection molding machine in 1983. The electric press, also known as Electric Machine Technology (EMT), reduces operation costs by cutting energy consumption and also addresses some of the environmental concerns surrounding the hydraulic press.2.1.2ElectricElectric presses have been shown to be quieter, faster, and have a higher accuracy, however the machines are more expensive.2.1.3HybridHybrid injection molding machines take advantage of the best features of both hydraulic and electric systems. Hydraulic machines are the predominant type in most of the world, with the exception of Japan.2.2Injection unitThe injection unit melts the polymer resin and injects the polymer melt into the mold. The unit may be: ram fed or screw fed.The ram fed injection molding machine uses a hydraulically operated plunger to push the plastic through a heated region. The high viscosity melt is then spread into a thin layer by a "torpedo" to allow for better contact with the heated surfaces. The melt converges at a nozzle and is injected into the mold.Reciprocating screw A combination melting, softening, and injection unit in an injection molding machine. Another term for the injection screw. Reciprocating screws are capable of turning as they move back and forth.The reciprocating screw is used to compress, melt, and convey the material. The reciprocating screw consists of three zones (illustrated below):•feeding zone•compressing zone•metering zoneWhile the outside diameter of the screw remains constant, the depth of the flights on the reciprocating screw decreases from the feed zone to the beginning of the metering zone. These flights compress the material against the inside diameter of the barrel, which creates viscous (shear) heat. This shear heat is mainly responsible for melting the material. The heater bands outside the barrel help maintain the material in the molten state. Typically, a molding machine can have three or more heater bands or zones with different temperature settings.Injection molding reciprocating screw An extruder-type screw rotates within a cylinder, which is typically driven by a hydraulic drive mechanism. Plastic material is moved through the heated cylinder via the screw flights and the material becomes fluid. The injection nozzle is blocked by the previous shot, and this action causes the screw to pump itself backward through the cylinder. (During this step, material is plasticated and accumulated for the next shot.) When the mold clamp has locked, the injection phase takes place. At this time, the screw advances, acting as a ram. Simultaneously, the non-return valve closes off the escape passages in the screw and the screw serves as a solid plunger, moving the plastic ahead into the mold. When the injection stroke and holding cycle is completed, the screw is energized to return and the non-return valve opens, allowing plastic to flow forward from the cylinder again, thus repeating the cycle.2.2.1Feed hopperThe container holding a supply molding material to be fed to the screw. The hopper located over the barrel and the feed throat connects them.2.2.2Injection ramThe ram or screw that applies pressure on the molten plastic material to force it into the mold cavities.2.2.3Injection screwThe reciprocating-screw machine is the most common. This design uses the same barrel for melting and injection of plastic.The alternative unit involves the use of separate barrels for plasticizing and injecting the polymer. This type is called a screw-preplasticizer machine or two-stage machine. Plastic pellets are fed from a hopper into the first stage, which uses a screw to drive the polymer forward and melt it. This barrel feeds a second barrel, which uses a plunger to inject the melt into the mold. Older machines used one plunger-driven barrel to melt and inject the plastic. These machines are referred to as plunger-type injection molding machines.2.2.4BarrelBarrel is a major part that melts resins transmitted from hopper through screws and structured in a way that can heat up resins to the proper temperature. A band heater, which can control temper atures in five sections, is attached outside the barrel. Melted resins are supplied to the mold passing through barrel head, shot-off nozzle, and one-touch nozzle.2.2.5Injection cylinderHydraulic motor located inside bearing box, which is connected to injection cylinder load, rotates screw, and the melted resins are measures at the nose of screw. There are many types of injection cylinders that supply necessary power to inject resins according to the characteristics of resins and product types at appropriate speed and pressure. This model employs the double cylinder type. Injection cylinder is composed of cylinder body, piston, and piston load.2.3Clamping unitThe clamping unit holds the mold together, opens and closes it automatically, and ejects the finished part. The mechanism may be of several designs, either mechanical, hydraulic or hydromechanical.Toggle clamps - a type clamping unit include various designs. An actuator moves the crosshead forward, extending the toggle links to push the moving platen toward a closed position. At the beginning of the movement, mechanical advantage is low and speed is high; but near the end of the stroke, the reverse is true. Thus, toggle clamps provide both high speed and high force at different points in the cycle when they are desirable. They are actuated either by hydraulic cylinders or ball screws driven by electric motors. Toggle-clamp units seem most suited to relatively low-tonnage machines.Two clamping designs: (a) one possible toggle clamp design (1) open and (2) closed; and (b) hydraulic clamping (1) open and (2) closed. Tie rods used to guide movuing platens not shown.Hydraulic clamps are used on higher-tonnage injection molding machines, typically in the range 1300 to 8900 kN (150 to 1000 tons). These units are also more flexible than toggle clamps in terms of setting the tonnage at given positions during the stroke.Hydraulic Clamping System is using the direct hydraulic clamp of which the tolerance is still and below 1 %, of course, better than the toggle system. In addition, the Low Pressure Protection Device is higher than the toggle system for 10 times so that the protection for the precision and expensive mold is very good. The clamping force is focus on the central for evenly distribution that can make the adjustment of the mold flatness in automatically. Hydromechanical clamps -clamping units are designed for large tonnages, usually above 8900 kN (1000 tons); they operate by (1) using hydraulic cylinders to rapidly move the mold toward closing position, (2) locking the position by mechanical means, and (3) using high pressure hydraulic cylinders to finally close the mold and build tonnage.2.3.1Injection moldThere are two main types of injection molds: cold runner (two plate and three plate designs) and hot runner– the more common of the runnerless molds.2.3.2Injection platensSteel plates on a molding machine to which the mold is attached. Generally, two platens are used; one being stationary and the other moveable, actuated hydraulically to open and close the mold. It actually provide place to mount the mould. It contains threaded holes on which mould can be mounted using clamps.2.3.3Clamping cylinderA device that actuates the chuck through the aid of pneumatic or hydraulic energy.2.3.4Tie BarTie bars support clamping power, and 4 tie bars are located between the fixing platen and the support platen.3 Injection mouldFrom Wikipedia, the free encyclopediaMold A hollow form or cavity into which molten plastic is forced to give the shape of the required component. The term generally refers to the whole assembly of parts that make up the section of the molding equipment in which the parts are formed. Also called a tool or die. Moulds separate into at least two halves (called the core and the cavity) to permit the part to be extracted; in general the shape of a part must be such that it will not be locked into the mould. For example, sides of objects typically cannot be parallel with the direction of draw (the direction in which the core and cavity separate from each other). They are angled slightly; examination of most household objects made from plastic will show this aspect of design, known as draft. Parts that are "bucket-like" tend to shrink onto the core while cooling and, after the cavity is pulled away, are typically ejected using pins. Parts can be easily welded together after moulding to allow for a hollow part (like a water jug or doll's head) that couldn't physically be designed as one mould.More complex parts are formed using more complex moulds, which may require moveable sections, called slides, which are inserted into the mould to form particular features that cannot be formed using only a core and a cavity, but are then withdrawn to allow the part to be released. Some moulds even allow previously moulded parts to be re-inserted to allow a new plastic layer to form around the first part. This system can allow for production of fully tyred wheels.Traditionally, moulds have been very expensive to manufacture; therefore, they were usually only used in mass production where thousands of parts are being produced.Molds require: Engineering and design, special materials, machinery and highly skilled personnel to manufacture, assemble and test them.Cold-runner moldCold-runner mold Developed to provide for injection of thermoset material either directly into the cavity or through a small sub-runner and gate into the cavity. It may be compared to the hot-runner molds with the exception that the manifold section is cooled rather than heated to maintain softened but uncured material. The cavity and core plates are electrically heated to normal molding temperature and insulated from the cooler manifold section.3.1.1Types of Cold Runner MoldsThere are two major types of cold runner molds: two plate and three plate.3.1.2Two plate moldA two plate cold runner mold is the simplest type of mold. It is called a two plate mold because there is one parting plane, and the mold splits into two halves. The runner system must be located on this parting plane; thus the part can only be gated on its perimeter.3.1.3Three plate moldA three plate mold differs from a two plate in that it has two parting planes, and the mold splits into three sections every time the part is ejected. Since the mold has two parting planes, the runner system can be located on one, and the part on the other. Three plate molds are used because of their flexibility in gating location. A part can be gated virtually anywhere along its surface.3.1.4AdvantagesThe mold design is very simple, and much cheaper than a hot runner system. The mold requires less maintenance and less skill to set up and operate. Color changes are also very easy, since all of the plastic in the mold is ejected with each cycle.3.1.5DisadvantagesThe obvious disadvantage of this system is the waste plastic generated. The runners are either disposed of, or reground and reprocessed with the original material. This adds a step in the manufacturing process. Also, regrind will increase variation in the injection molding process, and could decrease the plastic's mechanical properties.3.1.6Hot runner moldHot-runner mold -injection mold in which the runners are kept hot and insulated from the chilled cavities. Plastic freezeoff occurs at gate of cavity; runners are in a separate plate so they are not, as is the case usually, ejected with the piece.Hot runner molds are two plate molds with a heated runner system inside one half of the mold.A hot runner system is divided into two parts: the manifold and the drops. The manifold has channels that convey the plastic on a single plane, parallel to the parting line, to a point abovethe cavity. The drops, situated perpendicular to the manifold, convey the plastic from the manifold to the part.3.1.7Types of Hot Runner MoldsThere are many variations of hot runner systems. Generally, hot runner systems are designated by how the plastic is heated. There are internally and externally heated drops and manifolds.3.1.8Externally heated hot runnersExternally heated hot runner channels have the lowest pressure drop of any runner system (because there is no heater obstructing flow and all the plastic is molten), and they are better for color changes none of the plastic in the runner system freezes. There are no places for material to hang up and degrade, so externally heated systems are good for thermally sensitive materials.3.1.9Internally heated hot runnersInternally heated runner systems require higher molding pressures, and color changes are very difficult. There are many places for material to hang up and degrade, so thermally sensitive materials should not be used. Internally heated drops offer better gate tip control. Internally heated systems also better separate runner heat from the mold because an insulating frozen layer is formed against the steel wall on the inside of the flow channels.3.1.10 insulated hot runnersA special type of hot runner system is an insulated runner. An insulated runner is not heated; the runner channels are extremely thick and stay molten during constant cycling. This system is very inexpensive, and offers the flexible gating advantages of other hot runners and the elimination of gates without the added cost of the manifold and drops of a heated hot runner system. Color changes are very easy. Unfortunately, these runner systems offer no control, and only commodity plastics like PP and PE can be used. If the mold stops cycling for some reason, the runner system will freeze and the mold has to be split to remove it. Insulated runners are usually used to make low tolerance parts like cups and frisbees.3.1.11 DisadvantagesHot-runner mold is much more expensive than a cold runner, it requires costly maintenance, and requires more skill to operate. Color changes with hot runner molds can be difficult, since it is virtually impossible to remove all of the plastic from an internal runner system.3.1.12 AdvantagesThey can completely eliminate runner scrap, so there are no runners to sort from the parts, and no runners to throw away or regrind and remix into the original material. Hot runners are popular in high production parts, especially with a lot of cavities.Advantages Hot Runner System Over a Cold Runner System include:•no runners to disconnect from the molded parts•no runners to remove or regrind, thus no need for process/ robotics to remove them•having no runners reduces the possibility of contamination•lower injection pressures•lower clamping pressure•consistent heat at processing temperature within the cavity•cooling time is actually shorter (as there is no need for thicker, longer-cycle runners)•shot size is reduced by runner weight•cleaner molding process (no regrinding necessary)•nozzle freeze and sprue sticking issues eliminated中文翻译注塑模具设计与制造2 注射机选自《维基百科》注射机由两个基本部分组成,注射装置和夹紧装置。
注塑模具专业英语 塑胶模具英语 注塑成型专业英语 Injection Mould English
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横向滑板CRT (cathoder-ray tube) 阴极射线管crush 压碎cryogenic 低温学的crystal 结晶状的cubic 立方的,立方体的cup (使)成杯状,引伸curable 可矫正的curvature 弧线curve 使弯曲cutter bit 刀头,刀片cyanide 氰化物complicated 复杂的dash 破折号daylight 板距decline 下落,下降,减少deform (使)变形demonstrate 证明depict 描述deposite 放置depression 凹穴descend 下降desirable 合适的detail 细节,详情deterioration 退化,恶化determine 决定diagrammmatic 图解的,图表的dictate 支配die 模具,冲模,凹模dielectric 电介质die-set 模架digital 数字式数字dimensional 尺寸的,空间的discharge 放电,卸下,排出discharge 卸下discrete 离散的,分立的dislodge 拉出,取出dissolution 结束distinct 不同的,显著的distort 扭曲distort (使)变形,扭曲distributed system 分布式系统dowel 销子dramaticlly 显著地drastic 激烈的draughting 绘图draughtsman 起草人drawing 制图drill press 钻床drum 鼓轮dual 双的,双重的ductility 延展性dynamic 动力的edge 边缘e.g.(exempli gratia) [拉]例如ejector 排出器ejector plate 顶出板ejector rob 顶杆elasticity 弹性electric dicharge machining 电火花加工electrode 电极electro-deposition 电铸elementary 基本的eliminate 消除,除去elongate (使)伸长,延长emerge 形成,显现emphasise 强调endeavour 尽力engagement 约束,接合enhance 提高,增强ensure 确保,保证erase 抹去,擦掉evaluation 评价,估价eventually 终于evolution 进展excecution 执行,完成execute 执行electrochemical machining 电化学加工exerte 施加experience 经验explosive 爆炸(性)的extend 伸展external 外部的extract 拔出extreme 极端extremely 非常地extremity 极端extrusion 挤压,挤出envisage 设想Fahrenheit 华氏温度fabricate 制作,制造flat-panel technology 平面(显示)技术facility 设备facing 端面车削fall within 属于,适合于fan 风扇far from 毫不,一点不,远非fatigue 疲劳feasible 可行的feature 特色,特征feed 进给feedback 反馈female 阴的,凹形的ferrule 套管文件系统fitter 装配工,钳工fix 使固定,安装fixed half and moving half 定模和动模facilitate 帮助flexibility 适应性,柔性flexible 柔韧的flow mark 流动斑点follow-on tool 连续模foregoing 在前的,前面的foretell 预测,预示,预言forge 锻造forming 成型four screen quadrants 四屏幕象限fracture 破裂free from 免于gap 裂口,间隙gearbox 齿轮箱govern 统治,支配,管理grain 纹理graphic 图解的grasp 抓住grid 格子,网格grind 磨,磨削,研磨grinding 磨光,磨削grinding machine 磨床gripper 抓爪,夹具groove 凹槽guide bush 导套guide pillar 导柱guide pillars and bushes 导柱和导套handset 电话听筒hardness 硬度hardware 硬件headstock 床头箱,主轴箱hexagonal 六角形的,六角的hindrance 障碍,障碍物hob 滚刀,冲头hollow-ware 空心件horizontal 水平的hose 软管,水管hyperbolic 双曲线的i.e. (id est) [拉]也就是identical 同样的identify 确定,识别idle 空闲的immediately 正好,恰好impact 冲击impart 给予implement 实现impossibility 不可能impression 型腔in contact with 接触in terms of 依据inasmuch (as) co因为,由于inch-to-metric conversions 英公制转换inclinable 可倾斜的inclusion 内含物inconspicuous 不显眼的incorporate 合并,混合indentation 压痕indenter 压头independently 独自地,独立地inevitably 不可避免地inexpensive 便宜的inherently 固有的injection mould 注塑模injection 注射in-line-of-draw 直接脱模insert 嵌件inserted die 嵌入式凹模inspection 检查,监督installation 安装integration 集成intelligent 智能的intentinonally 加强地,集中地interface 界面internal 内部的interpolation 插值法investment casting 熔模铸造irregular 不规则的,无规律irrespective of 不论,不管irrespective 不顾的,不考虑的issue 发布,发出joint line 结合线kerosene 煤油keyboard 健盘knock 敲,敲打lance 切缝lathe 车床latitude 自由lay out 布置limitation 限度,限制,局限(性) local intelligence 局部智能locate 定位logic 逻辑longitudinal 纵向的longitudinally 纵向的look upon 视作,看待lubrication 润滑machine shop 车间machine table 工作台machining 加工made-to-measure 定做maintenance 维护,维修majority 多数make use of 利用male 阳的,凸形的malfunction 故障mandrel 心轴manifestation 表现,显示massiveness 厚实,大块measure 大小,度量microcomputer 微型计算机microns 微米microprocessor 微处理器mild steel 低碳钢milling machine 铣床mineral 矿物,矿产minimise 把减到最少,最小化minute 微小的mirror image 镜像mirror 镜子moderate 适度的modification 修改,修正modulus 系数mold 模,铸模mold 制模,造型monitor 监控monograph 专著more often than not 常常motivation 动机mould split line 模具分型线moulding 注塑件move away from 抛弃multi-imprssion mould 多型腔模narrow 狭窄的NC (numerical control) 数控nevertheless 然而,不过nonferrous 不含铁的,非铁的normally 通常地novice 新手,初学者nozzle 喷嘴,注口numerical 数字的objectionable 有异议的,讨厌的observe 观察obviously 明显地off-line 脱机的on-line 联机operational 操作的,运作的opportunity 时机,机会opposing 对立的,对面的opposite 反面optimization 最优化orient 确定方向orthodox 正统的,正规的overall 全面的,全部的overbend 过度弯曲overcome 克服,战胜overlaping 重叠overriding 主要的,占优势的opposite 对立的,对面的pack 包装package 包装pallet 货盘panel 面板paraffin 石蜡parallel 平行的penetration 穿透peripheral 外围的periphery 外围permit 许可,允许pessure casting 压力铸造pillar 柱子,导柱pin 销,栓,钉pin-point gate 针点式浇口piston 活塞plan view 主视图plasma 等离子plastic 塑料platen 压板plotter 绘图机plunge 翻孔plunge 投入plunger 柱塞pocket-size 袖珍portray 描绘pot 壶pour 灌,注practicable 行得通的preferable 更好的,更可取的preliminary 初步的,预备的press setter 装模工press 压,压床,冲床,压力机prevent 妨碍primarily 主要地procedure 步骤,方法,程序productivity 生产力profile 轮廓progressively 渐进地project 项目project 凸出projection 突出部分proper 本身的property 特性prototype 原形proximity 接近prudent 谨慎的punch 冲孔punch shapper tool 刨模机punch-cum-blanking die 凹凸模punched tape 穿孔带purchase 买,购买push back pin 回程杆pyrometer 高温计quality 质量quandrant 象限quantity 量,数量quench 淬火radial 放射状的ram 撞锤rapid 迅速的rapidly 迅速地raster 光栅raw 未加工的raw material 原材料ream 铰大reaming 扩孔,铰孔recall 记起,想起recede 收回,后退recess 凹槽,凹座,凹进处redundancy 过多re-entrant 凹入的refer 指,涉及,谈及reference 参照,参考refresh display 刷新显示register ring 定位环register 记录,显示,记数regrind 再磨研relative 相当的,比较的relay 继电器release 释放relegate 把降低到reliability 可靠性relief valves 安全阀relief 解除relieve 减轻,解除remainder 剩余物,其余部分removal 取出remove 切除,切削reposition 重新安排represent 代表,象征reputable 有名的,受尊敬的reservoir 容器,储存器resident 驻存的resist 抵抗resistance 阻力,抵抗resolution 分辨率respective 分别的,各自的respond 响应,作出反应responsibility 责任restrain 抑制restrict 限制,限定restriction 限制retain 保持,保留retaining plate 顶出固定板reveal 显示,展现reversal 反向right-angled 成直角的rigidity 钢度rod 杆,棒rotate (使)旋转rough machining 粗加工rough 粗略的routine 程序rubber 橡胶runner and gate systems 流道和浇口系统sand casting 砂型铸造satisfactorily 满意地saw 锯子scale 硬壳score 刻划scrap 废料,边角料,切屑screwcutting 切螺纹seal 密封section cutting plane 剖切面secure 固定secure 紧固,夹紧,固定segment 分割sensitive 敏感的sequence 次序sequential 相继的seriously 严重地servomechanism 伺服机构servomotor 伺服马达setter 安装者set-up 机构sever 切断severity 严重shaded 阴影的shank 柄shear 剪,切shot 注射shrink 收缩side sectional view 侧视图signal 信号similarity 类似simplicity 简单single-point cutting tool 单刃刀具situate 使位于,使处于slide 滑动,滑落slideway 导轨slot 槽slug 嵌条soak 浸,泡,均热software 软件solid 立体,固体solidify (使)凝固solidify (使)固化solution 溶液sophisiticated 尖端的,完善的sound 结实的,坚固的spark erosion 火花蚀刻spindle 主轴spline 花键split 侧向分型,分型spool 线轴springback 反弹spring-loaded 装弹簧的sprue bush 主流道衬套sprue puller 浇道拉杆square 使成方形Servomechanism Laboratoies 伺服机构实验室stage 阶段standardisation 标准化startling 令人吃惊的steadily 稳定地step-by-step 逐步stickiness 粘性stiffness 刚度stock 毛坯,坯料storage tube display 储存管显示storage 储存器straightforward 直接的strain 应变strength 强度stress 压力,应力stress-strain 应力--应变stretch 伸展strike 冲击stringent 严厉的stripper 推板stroke 冲程,行程structrural build-up 结构上形成的sub-base 垫板subject 使受到submerge 淹没subsequent 后来的subsequently 后来,随后substantial 实质的substitute 代替,替换subtract 减,减去suitable 合适的,适当的suitably 合适地sunk 下沉,下陷superior 上好的susceptible 易受影响的sweep away 扫过symmetrical 对称的synchronize 同步,同时发生tactile 触觉的,有触觉的tailstock 尾架tapered 锥形的tapping 攻丝technique 技术tempering 回火tendency 趋向,倾向tensile 拉力的,可拉伸的tension 拉紧,张紧terminal 终端机terminology 术语,用辞theoretically 理论地thereby 因此,从而thermoplastic 热塑性的thermoplastic 热塑性塑料thermoset 热固性thoroughly 十分地,彻底地thread pitch 螺距thread 螺纹thrown up 推上tilt 倾斜,翘起tolerance 公差two-plate mould 双板式注射模tong 火钳tonnage 吨位,总吨数tool point 刀锋tool room 工具车间toolholder 刀夹,工具柄toolmaker 模具制造者toolpost grinder 工具磨床toolpost 刀架torsional 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塑料模具设计外文翻译资料
外文翻译-模具类注塑机模具设计
外文翻译-模具类注塑机模具设计外文翻译毕业设计题目:操纵机构及其面板凸轮机构模具设计原文1:Plastic Material Molding译文1:塑料成型原文2:The Injection-molding Maching 译文2:注塑机Plastic Material MoldingPlastic objects are formed by comperssion,transfer,and injection molding.Other processes arecasting, extrusion and laminating, filament winding, sheet forming, jointing, foaming, andmaching. Some of these and still otherrs are used for rubber. A reason for a variety of processes isthat different materials must be worked in differentways. Also, each methods is advantageous for certain kind of product(Table 1)Table 1 Characteristics of Forming and Shaping Processesfor Plastics and Composite Materialsprocess CharacteristicsExtrusion Long, uniform, solid or hollow complex cross-sections;high production rates; low tooling costs; widetolerrances.Injection molding Complex shapes of various sizes, eliminating assembly;high production rates; costly tooling; good dimensionalaccurancy.Structural foam molding Large parts with high stiffness-to-weight ratio; lessexpensive tooling than in injection molding; lowproduction rates.Blow molding Hollow thin-walled parts of various sizes; highproduction rates and low cost for making containers.Rotational molding Large hollow shapes of relatively simple shape;lowtooling cost; low production rates.Thermoforming Shallow or relatively deep cavities; low tooling costs;medium production rates.Compression molding Parts similar to impression-die forging;relativelyinpensive tooling; medium production rates.Transfer molding More complex parts than compression molding andhigher production rates; some scrap loss; mediumtooling cost.1Casting Simple or intricate shapes made with flexible molds;low production rates.Processing of composite materials Long cycle time; tolerances and tooling cost depend onprocess.There are two main steps in the manufacture of plastic products. The first is a chemical process to create the resin. The second is to mixand shape all the material into the finished article or product.1.1 Compression MoldingIn compression molding, a preshaped charge of material, a premeasured volume of powder, or a viscous mixture of liquid redin and filler material is placed directly into a heated mold cavity. Forming is done under pressure from a plug or from the upper half of the die (Figer 1). Compression molding results in the formation of flash (if additional plastic is forced between the mold halves, because of a poor mold fit or wear, it is called flash.), which is subsequently removed by trimming or other means.Typical parts made are dishes, handles, container caps, fittings, electrical and electronic components, washing-machine agitators, and housings. Fiber-reinforced parts with long chopped fibers are formed by this process exclusively.Compression molding is used mainly with thermosetting plastics, with the original material being in a partially ploymerized state. Cross-linking (in these ploymers, additional element link one chain to another. The best example is the use of sulfur to cross-link elastomers to create automobile tires) is completed in the heated die; curing times rang from0.5 to 5 minutes, depending on the material and on part thickness and geometry. The thicker the material is, the longer it will take to cure. Elastomers are also shaped by compression molding.Three types of compression molds are available as follows:2Figuer 1 Typres of compression moldinga. flash-type, for shallow or flat parts,b. positive, for high density parts,c. semipositive, for quality production.1.2 Transfer MoldingTransfer molding represents a further development of compression molding. The uncured thermosetting material is placed in a heatedtransfer pot or chamber (Figer 2). After the materialis heated, it is injected into heated closed molds. A ram, a plunger, or a rotating-screw feeder (depending on the type of machine used)forces the material to flow through the narrow channels into the mold cavity.Typical parts made by transfer molding are electrical and electronic components and rubber and silicone parts. This process is particularly suitable for intricate parts with varying wall thickness.1.3 Injection MoldingInjection molding (injection of plastic into a catity of desired shape. The plastic is then cooled and ejected in its final form. Most consumer productions such as telephones, computer casings, and CD players are injection molded. ) is principally used for the production of thermoplastic parts, although some process has been made in developing a method for injection molding some3thermosetting materials.Figure 2 Sequence of operations in transfer molding forthermosetting plastics The problem of injection a melted plastic into a mold cavity from a reservoir melted material has been extremelydifficult to solve for thermosetting plastics which cure and harden such conditions within a few minutes. The principle of injection molding is quite similar to that of die-casting. Plastic powder is loaded into thefeed hopper and a certain amount feeds into the heating chamber when the plunger draws back. The plastic powder under heat and pressures in the heating chamber becomes a fluid. After the mold is closed, the plunger moves forward, forcing some of the fluid plastic into the mold cavity under pressures. Since the mold in cooled by circulating cold water, the plastic hardens and the part may be ejected when the plunger draws back and the mold opens. Injection-molding machines can be arranged for manual operation, automatic single-cycle operation, and ful automatic operation. Typical machines produce molded parts weighing up to 22 ounces at the rate of four shots per minute, and it is possible on molded parts machines to obtain a rate of six shots per minute. The molds used are similar to the dies of a die-casting machine. The advantages of injection molding are as follows:1. A high molding speed adapted for mass production is possible,2. There is a wide choice of thermoplastic materials providing a variety of usefulproperties,3. It is possible to mold threads,(“sideways” racesses or projections of the molded part thatprevent its removal from the mold along the parting direction. They can accommodated4by specialized mold design such as sliders.), side holes, and large thin sections. 1.4 Thermoplastic Mold DesignBasically, there are two types of transfer mold: the conventional sprue type and the positive plunger type. In the sprue type the plastic performs are placed in a separate loading chamber above the mold cavity. One or more sprues (the runway between the injection machine's nozzle and the runners or the gate) lead down to the parting surface of the mold where they connect with gates to the mold cavity or cavities (Figer 3). Special press with a floating intermediate platen are especially useful for accommodating the two parting surface molds. The plunger acts directly on the plastic material, forcing it through the sprues and gates into the mold cavities. Heat and pressure must be maintained for a definite time for curing. When the part is cured the press is opened, breaking the sprues from the gates. The cull and sprues and raised upward, being held by a tapered, dovetailed projection machine on the end ofFigure 3 Schematic illustration of transfer moldingthe plunger. They can easily be removed from the dovetail by pushing horizontally. In a positive plunger-type transfer mold the sprue is eliminated so that the loading chamber extends through to the mold parting surface and connects directly with the gates (the entrance to the mold cavity). The positive plunger type is preferred, because themold is less complicated, and less material is wasted. Parts made by transfer molding have greater strength, more uniform densities, closer dimensional tolerances, and the parting plane (the separation plane of the two mold halves) requires less cleaning as compression molding.The following figure shows a typical two-plate mold and indicates the structure of mold and the arrangement of all parts in mold (Figure4).5Figure 4 The typical structure of two-plate mold作者:Yijun Huang国籍:china出处:Qinghua university press6塑料成型塑料制品一般是由压缩,传递和注塑成型等方法形成的。
注塑模具设计注射模具毕业课程设计外文文献翻译
The Injection MoldingThe Introduction of MoldsThe mold is at the core of a plastic manufacturing process because its cavity gives a part its shape. This makes the mold at least as critical-and many cases more so-for the quality of the end product as, for example, the plasticiting unit or other components of the processing equipment.Mold MaterialDepending on the processing parameters for the various processing methods as well as the length of the production run, the number of finished products to be produced, molds for plastics processing must satisfy a great variety of requirements. It is therefore not surprising that molds can be made from a very broad spectrum of materials, including-from a technical standpoint-such exotic materials as paper matched and plaster. However, because most processes require high pressures, often combined with high temperatures, metals still represent by far the most important material group, with steel being the predominant metal. It is interesting in this regard that, in many cases, the selection of the mold material is not only a question of material properties and an optimum price-to-performance ratio but also that the methods used to produce the mold, and thus the entire design, can be influenced.A typical example can be seen in the choice between cast metal molds, with their very different cooling systems, compared to machined molds. In addition, the production technique can also have an effect; for instance, it is often reported that, for the sake of simplicity, a prototype mold is frequently machined from solid stock with the aid of the latest technology such as computer-aided (CAD) and computer-integrated manufacturing (CIM S). In contrast to the previously used methods based on the use of patterns, the use of CAD and CAM often represents the more economical solution today, not only because this production capability is available pin-house but also because with any other technique an order would have to be placed with an outside supplier.Overall, although high-grade materials are often used, as a rule standard materials are used in mold making. New, state-of-the art (high-performance) materials, such as ceramics, for instance, are almost completely absent. This may be related to the fact that their desirable characteristics, such as constant properties up to very high temperatures, are not required on molds, whereas their negative characteristics, e. g. low tensile strength and poor thermal conductivity, have a clearly related to ceramics, such as sintered material, is found in mild making only to a limited degree. This refers less to the modern materials and components produced by powder metallurgy, and possibly by hot isocratic pressing, than to sintered metals in the sense of porous, air-permeable materials.Removal of air from the cavity of a mold is necessary with many different processing methods, and it has been proposed many times that this can be accomplished using porous metallic materials. The advantages over specially fabricated venting devices, particularly in areas where melt flow fronts meet, I, e, at weld lines, are as obvious as the potential problem areas: on one hand, preventing the texture of such surfaces from becoming visible on the finished product, and on the other hand, preventing the microspores from quickly becoming clogged with residues (broken off flash, deposits from the molding material, so-called plate out, etc.). It is also interesting in this case that completely new possibilities with regard to mold design and processing technique result from the use of such materials.A. Design rulesThere are many rules for designing molds. These rules and standard practices are based on logic, past experience, convenience, and economy. For designing, mold making, and molding, it is usually of advantage to follow the rules. But occasionally, it may work out better if a rule is ignored and an alternative way is selected. In this text, the most common rules are noted, but the designer will learn only from experience which way to go. The designer must ever be open to new ideas and methods, to new molding and mold materials that may affect these rules.B. The basic mold1. Mold cavity spaceThe mold cavity space is a shape inside the mold, “excavated” in such a manner that when the molding material is forced into this space it will take on the shape of the cavity space and, therefore, the desired product. The principle of a mold is almost as old as human civilization. Molds have metals into sand forms. Such molds, which are still used today in foundries, can be used only once because the mold is destroyed to release the product after it has solidified. Today, we are looking for permanent molds that can be used over and over. Now molds are made from strong, durable materials, such as steel, or from softer aluminum or metal alloys and even from certain plastics where a long mold life is not required because the planned production is small. In injection molding the plastic is injected into the cavity space with high pressure, so the mold must be strong enough to resist the injection pressure without deforming.2. Number of cavitiesMany molds, particularly molds for larger products, are built for only cavity space, but many molds, especially large production molds, are built with 2 or more cavities. The reason for this is purely economical. It takes only little more time to inject several cavities than to inject one. For example, a 4-cavity mold requires only one-fourth of the machine time of asingle-cavity mold. Conversely, the production increases in proportion to the number of cavities. A mold with more cavities is more expensive to build than a single-cavity mold, but not necessarily 4 times as much as a single-cavity mold. But it may also require a larger machine with larger platen area and more clamping capacity, and because it will use 4 times the amount of plastic, it may need a large injection unit, so the machine hour cost will be higher than for a machine large enough for the smaller mold.3. Cavity shape and shrinkageThe shape of the cavity is essenti ally the “negative” of the shape of the desired product, with dimensional allowance added to allow for shrinking of the plastic. The shape of the cavity is usually created with chip-removing machine tools, or with electric discharge machining, with chemical etching, or by any new method that may be available to remove metal or build it up, such as galvanic processes. It may also be created by casting certain metals in plaster molds created from models of the product to be made, or by casting some suitable hard plastics. The cavity shape can be either cut directly into the mold plates or formed by putting inserts into the plates.C. Cavity and coreBy convention, the hollow portion of the cavity space is called the cavity. The matching, often raised portion of the cavity space is called the core. Most plastic products are cup-shaped. This does not mean that they look like a cup, but they do have an inside and an outside. The outside of the product is formed by the cavity, the inside by the core. The alternative to the cup shape is the flat shape. In this case, there is no specific convex portion, and sometimes, the core looks like a mirror image of the cavity. Typical examples for this are plastic knives, game chips, or round disks such as records. While these items are simple in appearance, they often present serious molding problems for ejection of the product. The reason for this is that all injection molding machines provide an ejection mechanism on the moving platen and the products tend to shrink onto and cling to the core, from where they are then ejected. Most injection molding machines do not provide ejection mechanisms on the injection side.Polymer ProcessingPolymer processing, in its most general context, involves the transformation of a solid (sometimes liquid) polymeric resin, which is in a random form (e.g., powder, pellets, beads), to a solid plastics product of specified shape, dimensions, and properties. This is achieved by means of a transformation process: extrusion, molding, calendaring, coating, thermoforming, etc. The process, in order to achieve the above objective, usually involves the following operations: solid transport, compression, heating, melting, mixing, shaping, cooling,solidification, and finishing. Obviously, these operations do not necessarily occur in sequence, and many of them take place simultaneously.Shaping is required in order to impart to the material the desired geometry and dimensions. It involves combinations of viscoelastic deformations and heat transfer, which are generally associated with solidification of the product from the melt.Shaping includes: two-dimensional operations, e.g. die forming, calendaring and coating; three-dimensional molding and forming operations. Two-dimensional processes are either of the continuous, steady state type (e.g. film and sheet extrusion, wire coating, paper and sheet coating, calendaring, fiber spinning, pipe and profile extrusion, etc.) or intermittent as in the case of extrusions associated with intermittent extrusion blow molding. Generally, molding operations are intermittent, and, thus, they tend to involve unsteady state conditions. Thermoforming, vacuum forming, and similar processes may be considered as secondary shaping operations, since they usually involve the reshaping of an already shaped form. In some cases, like blow molding, the process involves primary shaping (pair-son formation) and secondary shaping (pair son inflation).Shaping operations involve simultaneous or staggered fluid flow and heat transfer. In two-dimensional processes, solidification usually follows the shaping process, whereas solidification and shaping tend to take place simultaneously inside the mold in three dimensional processes. Flow regimes, depending on the nature of the material, the equipment, and the processing conditions, usually involve combinations of shear, extensional, and squeezing flows in conjunction with enclosed (contained) or free surface flows.The thermo-mechanical history experienced by the polymer during flow and solidification results in the development of microstructure (morphology, crystallinity, and orientation distributions) in the manufactured article. The ultimate properties of the article are closely related to the microstructure. Therefore, the control of the process and product quality must be based on an understanding of the interactions between resin properties, equipment design, operating conditions, thermo-mechanical history, microstructure, and ultimate product properties. Mathematical modeling and computer simulation have been employed to obtain an understanding of these interactions. Such an approach has gained more importance in view of the expanding utilization of computer design/computer assisted manufacturing/computer aided engineering (CAD/CAM/CAE) systems in conjunction with plastics processing.It will emphasize recent developments relating to the analysis and simulation of some important commercial process, with due consideration to elucidation of both thermo-mechanical history and microstructure development.As mentioned above, shaping operations involve combinations of fluid flow and heattransfer, with phase change, of a visco-elastic polymer melt. Both steady and unsteady state processes are encountered. A scientific analysis of operations of this type requires solving the relevant equations of continuity, motion, and energy (I. e. conservation equations).Injection MoldingMany different processes are used to transform plastic granules, powders, and liquids into final product. The plastic material is in moldable form, and is adaptable to various forming methods. In most cases thermoplastic materials are suitable for certain processes while thermosetting materials require other methods of forming. This is recognized by the fact that thermoplastics are usually heated to a soft state and then reshaped before cooling. Theromosets, on the other hand have not yet been polymerized before processing, and the chemical reaction takes place during the process, usually through heat, a catalyst, or pressure. It is important to remember this concept while studying the plastics manufacturing processes and the polymers used.Injection molding is by far the most widely used process of forming thermoplastic materials. It is also one of the oldest. Currently injection molding accounts for 30% of all plastics resin consumption. Since raw material can be converted by a single procedure, injection molding is suitable for mass production of plastics articles and automated one-step production of complex geometries. In most cases, finishing is not necessary. Typical products include toys, automotive parts, household articles, and consumer electronics goods,Since injection molding has a number of interdependent variables, it is a process of considerable complexity. The success of the injection molding operation is dependent not only in the proper setup of the machine variables, but also on eliminating shot-to-shot variations that are caused by the machine hydraulics, barrel temperature variations, and changes in material viscosity. Increasing shot-to-shot repeatability of machine variables helps produce parts with tighter tolerance, lowers the level of rejects, and increases product quality ( i.e., appearance and serviceability).The principal objective of any molding operation is the manufacture of products: to a specific quality level, in the shortest time, and using a repeatable and fully automatic cycle. Molders strive to reduce or eliminate rejected parts, or parts with a high added value such as appliance cases, the payoff of reduced rejects is high.A typical injection molding cycle or sequence consists of five phases:1 Injection or mold filling2 Packing or compression3 Holding4 Cooling5 Part ejectionInjection Molding OverviewProcessInjection molding is a cyclic process of forming plastic into a desired shape by forcingthe material under pressure into a cavity. The shaping is achieved by cooling (thermoplastics) or by a chemical reaction (thermosets). It is one of the most commonand versatile operations for mass production of complex plastics parts with excellent dimensional tolerance. It requires minimal or no finishing or assembly operations. In addition to thermoplastics and thermosets, the process is being extended to suchmaterials as fibers, ceramics, and powdered metals, with polymers as binders.ApplicationsApproximately 32 percent by weight of all plastics processed go through injection molding machines. Historically, the major milestones of injection molding include the invention of the reciprocating screw machine and various new alternative processes, and the application of computersimulation to the design and manufacture of plastics parts.Development of the injection molding machineSince its introduction in the early 1870s, the injection molding machine has undergone significantmodifications and improvements. In particular, the invention of the reciprocating screw machine hasrevolutionized the versatility and productivity of the thermoplastic injection molding process.Benefits of the reciprocating screwApart from obvious improvements in machine control and machine functions, the major development for the injection molding machine is the change from a plunger mechanism to a reciprocating screw. Although the plunger-type machine is inherently simple, its popularity waslimited due to the slow heating rate through pure conduction only. The reciprocating screw canplasticize the material more quickly and uniformly with its rotating motion, as shown in Figure 1. Inaddition, it is able to inject the molten polymer in a forward direction, as a plunger.Development of the injection molding processThe injection molding process was first used only with thermoplastic polymers. Advances in theunderstanding of materials, improvements in molding equipment, and the needs of specific industrysegments have expanded the use of the process to areas beyond its original scope. Alternative injection molding processesDuring the past two decades, numerous attempts have been made to develop injection moldingprocesses to produce parts with special design features and properties. Alternative processes derivedfrom conventional injection molding have created a new era for additional applications, more designfreedom, and special structural features. These efforts have resulted in a number of processes,including:Co-injection (sandwich) moldingFusible core injection molding)Gas-assisted injection moldingInjection-compression moldingLamellar (microlayer) injection moldinLive-feed injection moldingLow-pressure injection moldingPush-pull injection moldingReactive moldingStructural foam injection moldingThin-wall moldingComputer simulation of injection molding processesBecause of these extensions and their promising future, computer simulation of the process has alsoexpanded beyond the early "lay-flat," empirical cavity-filling estimates. Now, complex programs simulate post-filling behavior, reaction kinetics, and the use of two materials with different properties, or two distinct phases, during the process.The Simulation section provides information on using C-MOLD products.Among the Design topicsare several examples that illustrate how you can use CAE tools to improve your part and molddesign and optimize processing conditions.Co-injection (sandwich) moldingOverviewCo-injection molding involves sequential or concurrent injection of two different but compatible polymer melts into a cavity. The materials laminate and solidify. This process produces parts that have a laminated structure, with the core material embedded betweenthe layers of the skin material. This innovative process offers the inherent flexibility ofusing the optimal properties of each material or modifying the properties of the molded part.FIGURE 1. Four stages of co-injection molding. (a) Short shot of skin polymer melt (shown in dark green)is injected into the mold. (b) Injection of core polymer melt until cavity is nearly filled, as shown in (c). (d)Skin polymer is injected again, to purge the core polymer away from the sprue.Fusible core injection moldingOverviewThe fusible (lost, soluble) core injection molding process illustrated below producessingle-piece, hollow parts with complex internal geometry. This process molds a coreinside the plastic part. After the molding, the core will be physically melted or chemically dissolved, leaving its outer geometry as the internal shape of the plastic part.FIGURE 1. Fusible (lost, soluble) core injection moldingGas-assisted injection moldingGas-assisted processThe gas-assisted injection molding process begins with a partial or full injection ofpolymer melt into the mold cavity. Compressed gas is then injected into the core of the polymer melt to help fill and pack the mold. This process is illustrated below.FIGURE 1. Gas-assisted injection molding: (a) the electrical system, (b) the hydraulic system, (c) the control panel, and (d) the gas cylinder.Injection-compression moldingOverviewThe injection-compression molding process is an extension of conventional injection molding. After a pre-set amount of polymer melt is fed into an open cavity, it is compressed, as shown below. The compression can also take place when the polymer isto be injected. The primary advantage of this process is the ability to produce dimensionally stable, relatively stress-free parts, at a low clamp tonnage (typically 20 to 50 percent lower).Lamellar (microlayer) injection moldingOverviewThis process uses a feedblock and layer multipliers to combine melt streams from dual injection cylinders. It produces parts from multiple resins in distinct microlayers, as shown in Figure 1 below. Combining different resins in a layered structure enhances a number of properties, such as the gas barrier property, dimensional stability, heat resistance, and optical clarity.Live-feed injection moldingOverviewThe live-feed injection molding process applies oscillating pressure at multiple polymer entrances to cause the melt to oscillate, as shown in the illustration below. The action of the pistons keeps the material in the gates molten while different layers of molecular or fiber orientation are being built up in the mold due to solidification. This process provides a means of making simple or complex parts that are free from voids, cracks, sink marks, and weld-line defects.Low-pressure injection moldingOverviewLow-pressure injection molding is essentially an optimized extension of conventional injection molding (see Figure 1). Low pressure can be achieved by properly programming the screw revolutions per minute, hydraulic back pressure, and screw speed to controlthe melt temperature and the injection speed. It also makes use of a generous gate size ora n reduce umber of valve gates that open and close sequentially to reduce the flow length. Thepacking stage is eliminated with a generally slow and controlled injection speed. The benefits of low-pressure injection molding include a reduction of the clamp force tonnage requirement, less costly molds and presses, and lower stress in the molded parts.Push-pull injection moldingOverviewThe push-pull injection molding process uses a conventional twin-component injection system and a two-gate mold to force material to flow back and forth between a master injection unit and a secondary injection unit, as shown below. This process eliminatesweld lines, voids, and cracks, and controls the fiber orientation.Reactive moldingProcessingMajor reactive molding processes include reactive injection molding (RIM), and composites processing, such as resin transfer molding (RTM) and structural reactive injection molding (SRIM).The typically low viscosity of the reactive materials permits large and complex parts to be moldedwith relatively lower pressure and clamp tonnage than required for thermoplastics molding. relatively For example, to make high-strength and low-volume large parts, RTM and SRIM can be used to include a preform made of long fibers. Another area that is receiving more attention than ever before is the encapsulation of microelectronic IC chips.The adaptation of injection molding to these materials includes only a small increase in temperature in the feed mechanism (barrel) to avoid pre-curing. The cavity, however, is usually hot enough to initiate chemical cross-linking. As the warm pre-polymer is forced into the cavity, heat is added from the cavity wall, from viscous (frictional) heating of the flow, and from the heat released by the reacting components. The temperature of the part often exceeds the temperature of the mold. When the reaction is sufficiently advanced for the part to be rigid (even at a high temperature) the cycle is complete and the part is ejected.Design considerationsThe mold and process design for injection molding of reactive materials is much more complexbecause of the chemical reaction that takes place during the filling and post-filling stages. For instance, slow filling often causes premature gelling and a resultant short shot, while fast fillingcould induce turbulent flow that creates internal porosity. Improper control of mold-wall temperature and/or inadequate part thickness will either give rise to moldability problems duringinjection, or cause scorching of the materials. Computer simulation is generally recognized as amore cost-effective tool than the conventional, time-consuming trial-and-error method for tool andprocess debugging.Structural foam injection moldingOverviewStructural foam molding produces parts consisting of solid external skin surfaces surrounding an inner cellular (or foam) core, as illustrated in Figure 1 below. This processis suitable for large, thick parts that are subject to bending loads in their end-use application. Structural foam parts can be produced with both low and high pressure, withnitrogen gas or chemical blowing agents.Thin-wall moldingOverviewThe term "thin-wall" is relative. Conventional plastic parts are typically 2 to 4 mm thick. Thin-wall designs are called "advanced" when thicknesses range from 1.2 to 2 mm, and "leading-edge" when the dimension is below 1.2 mm. Another definition of thin-wall molding is based on the flow-length-to-wall-thickness ratios. Typical ratios for thesethin-wall applications range from 100:1 to 150:1 or more.Typical applicationsThin-wall molding is more popular in portable communication and computing equipment, whichdemand plastic shells that are much thinner yet still provide the same mechanical strength as conventional parts.ProcessingBecause thin-wall parts freeze off quickly, they require high melt temperatures, high injectio speeds, and very high injection pressures if multiple gates or sequential valve gating are not an optimized ram-speed profile helps to reduce the pressure requirement.Due to the high velocity and shear rate in thin-wall molding, orientation occurs more readily help minimize anisotropic shrinkage in thin-wall parts, it is important to pack the part adequately while the core is still molten.Injection molding machineComponentsFor thermoplastics, the injection molding machine converts granular or pelleted rawplastic into final molded parts via a melt, inject, pack, and cool cycle. A typical injection molding machine consists of the following major components, as illustrated in Figure 1 below.Machine functionInjection molding machines can be generally classified into three categories, based on machinefunction:General-purpose machinesPrecision, tight-tolerance machinesHigh-speed, thin-wall machinesAuxiliary equipmentThe major equipment auxiliary to an injection molding machine includes resin dryers, materials-handling equipment, granulators, mold-temperature controllers and chillers, part-removal robots, and part-handling equipment.中文翻译注塑模设计模具简介模具型腔可赋予制品其形状,因此在塑料加工过程中模具处于非常重要的地位,这使得模具对于产品最终质量的影响与塑化机构和其他成型设备的部件一样关键,有时甚至更重要。
注塑模具设计技术中英文对照外文翻译文献
中英文资料对照外文翻译英文:Design and Technology of the Injection Mold1、3D solid model to replace the center layer modelThe traditional injection molding simulation software based on products of the center layer model. The user must first be thin-walled plastic products abstract into approximate plane and curved surface, the surface is called the center layer. In the center layer to generate two-dimensional planar triangular meshes, the use of these two-dimensional triangular mesh finite element method, and the final result of the analysis in the surface display. Injection product model using3D solid model, the two models are inconsistent, two modeling inevitable. But because of injection molding product shape is complex and diverse, the myriads of changes from athree-dimensional entity, abstraction of the center layer is a very difficult job, extraction process is very cumbersome and time-consuming, so the design of simulation software have fear of difficulty, it has become widely used in injection molding simulation software the bottleneck.HSCAE3D is largely accepted3D solid / surface model of the STL file format. Now the mainstream CAD/CAM system, such as UG, Pro/ENGINEER, CATIA and SolidWorks, can output high quality STL format file. That is to say, the user can use any commercial CAD/CAE systems to generate the desired products3D geometric model of the STL format file, HSCAE3D can automatically add the STL file into a finite element mesh model, through the surface matching and introduction of a new boundary conditions to ensure coordination of corresponding surface flow, based on3D solid model of analysis, and display of three-dimensional analysis results, replacing the center layer simulation technology to abstract the center layer, and then generate mesh this complicated steps, broke through system simulation application bottlenecks, greatly reducing the burden of user modeling, reduces the technical requirement of the user, the user training time from the past few weeks shorter for a fewhours. Figure 1 is based on the central layer model and surface model based on 3D solid / flow analysis simulation comparison chart.2、Finite element, finite difference, the control volume methodsInjection molding products are thin products, products in the thickness direction of size is much smaller than the other two dimensions, temperature and other physical quantities in the thickness direction of the change is very large, if the use of a simple finite element and finite difference method will cause analysis time is too long, can not meet the actual needs of mold design and manufacturing. We in the flow plane by using finite element method, the thickness direction by using finite difference method, were established and plane flow and thickness directions corresponding to the size of the grid and coupling, while the accuracy is guaranteed under the premise of the calculation speed to meet the need of engineering application, and using the control volume method is solved. The moving boundary problem in. For internal and external correspondence surface differences between products, can be divided into two parts the volume, and respectively formed the control equation, the junction of interpolation to ensure thatthe two part harmony contrast.3、Numerical analysis and artificial intelligence technologyOptimization of injection molding process parameters has been overwhelming majority of mold design staff concerns, the traditional CAE software while in computer simulation of a designated under the conditions of the injection molding conditions, but is unable to automatically optimize the technical parameters. Using CAE software personnel must be set to different process conditions were multiple CAE analysis, combined with practical experience in the program were compared between, can get satisfactory process scheme. At the same time, the parts after the CAE analysis, the system will generate a large amount of information about the project ( product, process, analyzes the results ), which often results in a variety of data form, requiring the user to have the analysis and understanding of the results of CAE analysis ability, so the traditional CAE software is a kind of passive computational tools, can provide users with intuitionistic, effective engineering conclusion, to software users demand is too high, the influence of CAE system in the larger scope of application and popularization. In view of the above, HSCAE3D software in the original CAE system based on accurate calculationfunction, the knowledge engineering technology is introduced the system development, the use of artificial intelligence is the ability of thinking and reasoning, instead of the user to complete a large number of information analysis and processing work, directly provide guiding significance for the process of conclusions and recommendations, effectively solve the CAE of the complexity of the system and the requirements of the users of the contradiction between, shortening of the CAE system and the distance between the user, the simulation software by traditional " passive" computational tools to " active" optimization system. HSCAE3D system artificial intelligence technology will be applied to the initial design, the results of the analysis of CAE interpretation and evaluation, improvement and optimization analysis of3 aspects.译文:注塑模具设计的技术1.用三维实体模型取代中心层模型传统的注塑成形仿真软件基于制品的中心层模型。
注塑模具之模具设计与制造外文文献翻译、中英文翻译
外文翻译:Injection moulding for Mold Design and ManufactureThe mold is the manufacturing industry important craft foundation, in our country, the mold manufacture belongs to the special purpose equipment manufacturing industry. China although very already starts to make the mold and the use mold, but long-term has not formed the industry. Straight stabs 0 centuries 80's later periods, the Chinese mold industry only then drives into the development speedway. Recent years, not only the state-owned mold enterprise had the very big development, the three investments enterprise, the villages and towns (individual) the mold enterprise's development also quite rapidly.Although the Chinese mold industrial development rapid, but compares with the demand, obviously falls short of demand, its main gap concentrates precisely to, large-scale, is complex, the long life mold domain. As a result of in aspect and so on mold precision, life, manufacture cycle and productivity, China and the international average horizontal and the developed country still had a bigger disparity, therefore, needed massively to import the mold every year .The Chinese mold industry except must continue to sharpen the productivity; from now on will have emphatically to the profession internal structure adjustment and the state-of-art enhancement. The structure adjustment aspect, mainly is the enterprise structure to the specialized adjustment, the product structure to center the upscale mold development, to the import and export structure improvement, center the upscale automobile cover mold forming analysis and the structure improvement, the multi-purpose compound mold and the compound processing and the laser technology in the mold design manufacture application, the high-speed cutting, the super finishing and polished the technology, the information direction develops .The recent years, the mold profession structure adjustment and the organizational reform step enlarges, mainly displayed in, large-scale, precise, was complex, the long life, center the upscale mold and the mold standard letter development speed is higher than the common mold product; The plastic mold and the compression casting moldproportion increases; Specialized mold factory quantity and its productivity increase; "The three investments" and the private enterprise develops rapidly; The joint stock system transformation step speeds up and so on. Distributes from the area looked, take Zhujiang Delta and Yangtze River delta as central southeast coastal area development quickly to mid-west area, south development quickly to north. At present develops quickest, the mold produces the most centralized province is Guangdong and Zhejiang, places such as Jiangsu, Shanghai, Anhui and Shandong also has a bigger development in recent years.Although our country mold total quantity had at present achieved the suitable scale, the mold level also has the very big enhancement, after but design manufacture horizontal overall rise and fall industry developed country and so on Yu De, America, date, France, Italy many. The current existence question and the disparity mainly display in following several aspects:(1) The total quantity falls short of demandDomestic mold assembling one rate only, about 70%. Low-grade mold, center upscale mold assembling oneself rate only has 50% about.(2) The enterprise organizational structure, the product structure, the technical structure and the import and export structure does not gatherIn our country mold production factory to be most is from the labor mold workshop which produces assembles oneself (branch factory), from produces assembles oneself the proportion to reach as high as about 60%, but the overseas mold ultra 70% is the commodity mold. The specialized mold factory mostly is "large and complete", "small and entire" organization form, but overseas mostly is "small but", "is specially small and fine". Domestic large-scale, precise, complex, the long life mold accounts for the total quantity proportion to be insufficient 30%, but overseas in 50% above 2004 years, ratio of the mold import and export is 3.7:1, the import and export balances the after net import volume to amount to 1.32 billion US dollars, is world mold net import quantity biggest country .(3) The mold product level greatly is lower than the international standardThe production cycle actually is higher than the international water broadproduct level low mainly to display in the mold precision, cavity aspect and so on surface roughness, life and structure.(4) Develops the ability badly, economic efficiency unsatisfactory our country mold enterprise technical personnel proportion lowThe level is lower, also does not take the product development, and frequently is in the passive position in the market. Our country each mold staff average year creation output value approximately, ten thousand US dollars, overseas mold industry developed country mostly 15 to10, 000 US dollars, some reach as high as 25 to10, 000 US dollars, relative is our country quite part of molds enterprises also continues to use the workshop type management with it, truly realizes the enterprise which the modernized enterprise manages fewTo create the above disparity the reason to be very many, the mold long-term has not obtained the value besides the history in as the product which should have, as well as the most state-owned enterprises mechanism cannot adapt the market economy, but also has the following several reasons: .The mold material performance, the quality and the variety question often can affect the mold quality, the life and the cost, the domestically produced molding tool steel and overseas imports the steel products to compare has a bigger disparity. Plastic,plate, equipment energy balance, also direct influence mold level enhancement.RSP ToolingRapid Solidification Process (RSP) Tooling, is a spray forming technology tailored for producing molds and dies [2-4]. The approach combines rapid solidification processing and netshape materials processing in a single step. The general concept involves converting a mold design described by a CAD file to a tooling master using a suitable rapid prototyping (RP) technology such as stereolithography. A pattern transfer is made to a castable ceramic, typically alumina or fused silica. This is followed by spray forming a thick deposit of tool steel (or other alloy) on the pattern to capture the desired shape, surface texture and detail. The resultant metal block is cooled to room temperature and separated from the pattern. Typically, the deposit’s exterior walls are machined square, allowing it to be used as an insert in a holding block such as a MUD frame [5]. The overall turnaround time for tooling is about three days, stating with a master. Molds and dies produced in this way have been used for prototype and production runs in plastic injection molding and die casting.An important benefit of RSP Tooling is that it allows molds and dies to be made early in the design cycle for a component. True prototype parts can be manufactured to assess form, fit, and function using the same process planned for production. If the part is qualified, the tooling can be run in production as conventional tooling would. Use of a digital database and RP technology allows design modifications to be easily made.Experimental ProcedureAn alumina-base ceramic (Cotronics 780 [6]) was slurry cast using a silicone rubber master die, or freeze cast using a stereolithography master. After setting up, ceramic patterns were demolded, fired in a kiln, and cooled to room temperature. H13 tool steel was induction melted under a nitrogen atmosphere, superheated about100︒C, and pressure-fed into a bench-scale converging/diverging spray nozzle, designed and constructed in-house. An inert gas atmosphere within the spray apparatus minimized in-flight oxidation of the atomized droplets as they deposited onto the tool pattern at a rate of about 200 kg/h. Gas-to-metal mass flow ratio was approximately 0.5.For tensile property and hardness evaluation, the spray-formed material was sectioned using a wire EDM and surface ground to remove a 0.05 mm thickheat-affected zone. Samples were heat treated in a furnace that was purged with nitrogen. Each sample was coated with BN and placed in a sealed metal foil packet as a precautionary measure to prevent decarburization.Artificially aged samples were soaked for 1 hour at temperatures ranging from 400 to 700︒C, and air cooled. Conventionally heat treated H13 was austenitized at 1010︒C for 30 min., air quenched, and double tempered (2 hr plus 2 hr) at 538︒C.Microhardness was measured at room temperature using a Shimadzu Type M Vickers Hardness Tester by averaging ten microindentation readings. Microstructure of the etched (3% nital) tool steel was evaluated optically using an Olympus Model PME-3 metallograph and an Amray Model 1830 scanning electron microscope. Phase composition was analyzed via energy-dispersive spectroscopy (EDS). The size distribution of overspray powder was analyzed using a Microtrac Full Range Particle Analyzer after powder samples were sieved at 200 μm to remove coarse flakes. Sample density was evaluated by water displacement using Archimedes’ principle and a Mettler balance (Model AE100).A quasi 1-D computer code developed at INEEL was used to evaluate multiphase flow behavior inside the nozzle and free jet regions. The code's basic numerical technique solves the steadystate gas flow field through an adaptive grid, conservative variables approach and treats the droplet phase in a Lagrangian manner with full aerodynamic and energetic coupling between the droplets and transport gas. The liquid metal injection system is coupled to the throat gas dynamics, and effects of heat transfer and wall friction are included. The code also includes a nonequilibriumsolidification model that permits droplet undercooling and recalescence. The code was used to map out the temperature and velocity profile of the gas and atomized droplets within the nozzle and free jet regions.Results and DiscussionSpray forming is a robust rapid tooling technology that allows tool steel molds and dies to be produced in a straightforward manner. Each was spray formed using a ceramic pattern generated from a RP master.Particle and Gas BehaviorParticle mass frequency and cumulative mass distribution plots for H13 tool steel sprays are given in Figure 1. The mass median diameter was determined to be 56 μm by interpolation of size corresponding to 50% cumulative mass. The area mean diameter and volume mean diameter were calculated to be 53 μm and 139 μm, respectively. Geometric standard deviation, d=(d84/d16)½ , is 1.8, where d84 and d16 are particle diameters corresponding to 84% and 16% cumulative mass in Figure 1.Figure1. Cumulative mass and mass frequency plots of particles in H13 tool stepsprays.Figure2 gives computational results for the multiphase velocity flow field (Figure 2a), and H13 tool steel solid fraction (Figure2b), inside the nozzle and free jetregions. Gas velocity increases until reaching the location of the shock front, at which point it precipitously decreases, eventually decaying exponentially outside the nozzle. Small droplets are easily perturbed by the velocity field, accelerating inside the nozzle and decelerating outside. After reaching their terminal velocity, larger droplets (〜150 μm) are less perturbed by the flow field due to their greater momentum.It is well known that high particle cooling rates in the spray jet (103-106 K/s) and bulk deposit (1-100 K/min) are present during spray forming [7]. Most of the particles in the spray have undergone recalescence, resulting in a solid fraction of about 0.75. Calculated solid fraction profiles of small (〜30 μm) and large (〜150 μm) droplets with distance from the nozzle inlet, are shown in Figure 2b.Spray-Formed DepositsThis high heat extraction rate reduces erosion effects at the surface of the tool pattern. This allows relatively soft, castable ceramic pattern materials to be used that would not be satisfactory candidates for conventional metal casting processes. With suitable processing conditions, fine surface detail can be successfully transferred from the pattern to spray-formed mold. Surface roughness at the molding surface is pattern dependent. Slurry-cast commercial ceramics yield a surface roughness of about 1 μm Ra, suitable for many molding applications. Deposition of tool steel onto glass plates has yielded a specular surface finish of about 0.076 μm Ra. At the current state of development, dimensional repeatability of spray-formed molds, starting with a common master, is about ±0.2%.Figure 2. Calculated particle and gas behavior in nozzle and free jet regions.(a) Velocity profile.(b) Solid fraction.ChemistryThe chemistry of H13 tool steel is designed to allow the material to withstand the temperature, pressure, abrasion, and thermal cycling associated with demanding applications such as die casting. It is the most popular die casting alloy worldwide and second most popular tool steel for plastic injection molding. The steel has low carbon content (0.4 wt.%) to promote toughness, medium chromium content (5 wt.%) to provide good resistance to high temperature softening, 1 wt% Si to improve high temperature oxidation resistance, and small molybdenum and vanadium additions (about 1%) that form stable carbides to increase resistance to erosive wear[8]. Composition analysis was performed on H13 tool steel before and after spray forming.Results, summarized in Table 1, indicate no significant variation in alloy additions.MicrostructureThe size, shape, type, and distribution of carbides found in H13 tool steel is dictated by the processing method and heat treatment. Normally the commercial steel is machined in the mill annealed condition and heat treated(austenitized/quenched/tempered) prior to use. It is typically austenitized at about 1010︒C, quenched in air or oil, and carefully tempered two or three times at 540 to 650︒C to obtain the required combination of hardness, thermal fatigue resistance, and toughness.Commercial, forged, ferritic tool steels cannot be precipitation hardened becauseafter electroslag remelting at the steel mill, ingots are cast that cool slowly and formcoarse carbides. In contrast, rapid solidification of H13 tool steel causes alloying additions to remain largely in solution and to be more uniformly distributed in the matrix [9-11]. Properties can be tailored by artificial aging or conventional heat treatment.A benefit of artificial aging is that it bypasses the specific volume changes that occur during conventional heat treatment that can lead to tool distortion. These specific volume changes occur as the matrix phase transforms from ferrite to austenite to tempered martensite and must be accounted for in the original mold design. However, they cannot always be reliably predicted. Thin sections in the insert, which may be desirable from a design and production standpoint, are oftentimes not included as the material has a tendency to slump during austenitization or distort during quenching. Tool distortion is not observed during artificial aging ofspray-formed tool steels because there is no phase transformation.注塑模具之模具设计与制造模具是制造业的重要工艺基础,在我国,模具制造属于专用设备制造业。
注塑模具专业英语 塑胶模具英语 注塑成型专业英语 Injection Mould English
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横向滑板CRT (cathoder-ray tube) 阴极射线管crush 压碎cryogenic 低温学的crystal 结晶状的cubic 立方的,立方体的cup (使)成杯状,引伸curable 可矫正的curvature 弧线curve 使弯曲cutter bit 刀头,刀片cyanide 氰化物complicated 复杂的dash 破折号daylight 板距decline 下落,下降,减少deform (使)变形demonstrate 证明depict 描述deposite 放置depression 凹穴descend 下降desirable 合适的detail 细节,详情deterioration 退化,恶化determine 决定diagrammmatic 图解的,图表的dictate 支配die 模具,冲模,凹模dielectric 电介质die-set 模架digital 数字式数字dimensional 尺寸的,空间的discharge 放电,卸下,排出discharge 卸下discrete 离散的,分立的dislodge 拉出,取出dissolution 结束distinct 不同的,显著的distort 扭曲distort (使)变形,扭曲distributed system 分布式系统dowel 销子dramaticlly 显著地drastic 激烈的draughting 绘图draughtsman 起草人drawing 制图drill press 钻床drum 鼓轮dual 双的,双重的ductility 延展性dynamic 动力的edge 边缘e.g.(exempli gratia) [拉]例如ejector 排出器ejector plate 顶出板ejector rob 顶杆elasticity 弹性electric dicharge machining 电火花加工electrode 电极electro-deposition 电铸elementary 基本的eliminate 消除,除去elongate (使)伸长,延长emerge 形成,显现emphasise 强调endeavour 尽力engagement 约束,接合enhance 提高,增强ensure 确保,保证erase 抹去,擦掉evaluation 评价,估价eventually 终于evolution 进展excecution 执行,完成execute 执行electrochemical machining 电化学加工exerte 施加experience 经验explosive 爆炸(性)的extend 伸展external 外部的extract 拔出extreme 极端extremely 非常地extremity 极端extrusion 挤压,挤出envisage 设想Fahrenheit 华氏温度fabricate 制作,制造flat-panel technology 平面(显示)技术facility 设备facing 端面车削fall within 属于,适合于fan 风扇far from 毫不,一点不,远非fatigue 疲劳feasible 可行的feature 特色,特征feed 进给feedback 反馈female 阴的,凹形的ferrule 套管file system 文件系统fitter 装配工,钳工fix 使固定,安装fixed half and moving half 定模和动模facilitate 帮助flexibility 适应性,柔性flexible 柔韧的flow mark 流动斑点follow-on tool 连续模foregoing 在前的,前面的foretell 预测,预示,预言forge 锻造forming 成型four screen quadrants 四屏幕象限fracture 破裂free from 免于gap 裂口,间隙gearbox 齿轮箱govern 统治,支配,管理grain 纹理graphic 图解的grasp 抓住grid 格子,网格grind 磨,磨削,研磨grinding 磨光,磨削grinding machine 磨床gripper 抓爪,夹具groove 凹槽guide bush 导套guide pillar 导柱guide pillars and bushes 导柱和导套handset 电话听筒hardness 硬度hardware 硬件headstock 床头箱,主轴箱hexagonal 六角形的,六角的hindrance 障碍,障碍物hob 滚刀,冲头hollow-ware 空心件horizontal 水平的hose 软管,水管hyperbolic 双曲线的i.e. (id est) [拉]也就是identical 同样的identify 确定,识别idle 空闲的immediately 正好,恰好impact 冲击impart 给予implement 实现impossibility 不可能impression 型腔in contact with 接触in terms of 依据inasmuch (as) co因为,由于inch-to-metric conversions 英公制转换inclinable 可倾斜的inclusion 内含物inconspicuous 不显眼的incorporate 合并,混合indentation 压痕indenter 压头independently 独自地,独立地inevitably 不可避免地inexpensive 便宜的inherently 固有的injection mould 注塑模injection 注射in-line-of-draw 直接脱模insert 嵌件inserted die 嵌入式凹模inspection 检查,监督installation 安装integration 集成intelligent 智能的intentinonally 加强地,集中地interface 界面internal 内部的interpolation 插值法investment casting 熔模铸造irregular 不规则的,无规律irrespective of 不论,不管irrespective 不顾的,不考虑的issue 发布,发出joint line 结合线kerosene 煤油keyboard 健盘knock 敲,敲打lance 切缝lathe 车床latitude 自由lay out 布置limitation 限度,限制,局限(性) local intelligence 局部智能locate 定位logic 逻辑longitudinal 纵向的longitudinally 纵向的look upon 视作,看待lubrication 润滑machine shop 车间machine table 工作台machining 加工made-to-measure 定做maintenance 维护,维修majority 多数make use of 利用male 阳的,凸形的malfunction 故障mandrel 心轴manifestation 表现,显示massiveness 厚实,大块measure 大小,度量microcomputer 微型计算机microns 微米microprocessor 微处理器mild steel 低碳钢milling machine 铣床mineral 矿物,矿产minimise 把减到最少,最小化minute 微小的mirror image 镜像mirror 镜子moderate 适度的modification 修改,修正modulus 系数mold 模,铸模mold 制模,造型monitor 监控monograph 专著more often than not 常常motivation 动机mould split line 模具分型线moulding 注塑件move away from 抛弃multi-imprssion mould 多型腔模narrow 狭窄的NC (numerical control) 数控nevertheless 然而,不过nonferrous 不含铁的,非铁的normally 通常地novice 新手,初学者nozzle 喷嘴,注口numerical 数字的objectionable 有异议的,讨厌的observe 观察obviously 明显地off-line 脱机的on-line 联机operational 操作的,运作的opportunity 时机,机会opposing 对立的,对面的opposite 反面optimization 最优化orient 确定方向orthodox 正统的,正规的overall 全面的,全部的overbend 过度弯曲overcome 克服,战胜overlaping 重叠overriding 主要的,占优势的opposite 对立的,对面的pack 包装package 包装pallet 货盘panel 面板paraffin 石蜡parallel 平行的penetration 穿透peripheral 外围的periphery 外围permit 许可,允许pessure casting 压力铸造pillar 柱子,导柱pin 销,栓,钉pin-point gate 针点式浇口piston 活塞plan view 主视图plasma 等离子plastic 塑料platen 压板plotter 绘图机plunge 翻孔plunge 投入plunger 柱塞pocket-size 袖珍portray 描绘pot 壶pour 灌,注practicable 行得通的preferable 更好的,更可取的preliminary 初步的,预备的press setter 装模工press 压,压床,冲床,压力机prevent 妨碍primarily 主要地procedure 步骤,方法,程序productivity 生产力profile 轮廓progressively 渐进地project 项目project 凸出projection 突出部分proper 本身的property 特性prototype 原形proximity 接近prudent 谨慎的punch 冲孔punch shapper tool 刨模机punch-cum-blanking die 凹凸模punched tape 穿孔带purchase 买,购买push back pin 回程杆pyrometer 高温计quality 质量quandrant 象限quantity 量,数量quench 淬火radial 放射状的ram 撞锤rapid 迅速的rapidly 迅速地raster 光栅raw 未加工的raw material 原材料ream 铰大reaming 扩孔,铰孔recall 记起,想起recede 收回,后退recess 凹槽,凹座,凹进处redundancy 过多re-entrant 凹入的refer 指,涉及,谈及reference 参照,参考refresh display 刷新显示register ring 定位环register 记录,显示,记数regrind 再磨研relative 相当的,比较的relay 继电器release 释放relegate 把降低到reliability 可靠性relief valves 安全阀relief 解除relieve 减轻,解除remainder 剩余物,其余部分removal 取出remove 切除,切削reposition 重新安排represent 代表,象征reputable 有名的,受尊敬的reservoir 容器,储存器resident 驻存的resist 抵抗resistance 阻力,抵抗resolution 分辨率respective 分别的,各自的respond 响应,作出反应responsibility 责任restrain 抑制restrict 限制,限定restriction 限制retain 保持,保留retaining plate 顶出固定板reveal 显示,展现reversal 反向right-angled 成直角的rigidity 钢度rod 杆,棒rotate (使)旋转rough machining 粗加工rough 粗略的routine 程序rubber 橡胶runner and gate systems 流道和浇口系统sand casting 砂型铸造satisfactorily 满意地saw 锯子scale 硬壳score 刻划scrap 废料,边角料,切屑screwcutting 切螺纹seal 密封section cutting plane 剖切面secure 固定secure 紧固,夹紧,固定segment 分割sensitive 敏感的sequence 次序sequential 相继的seriously 严重地servomechanism 伺服机构servomotor 伺服马达setter 安装者set-up 机构sever 切断severity 严重shaded 阴影的shank 柄shear 剪,切shot 注射shrink 收缩side sectional view 侧视图signal 信号similarity 类似simplicity 简单single-point cutting tool 单刃刀具situate 使位于,使处于slide 滑动,滑落slideway 导轨slot 槽slug 嵌条soak 浸,泡,均热software 软件solid 立体,固体solidify (使)凝固solidify (使)固化solution 溶液sophisiticated 尖端的,完善的sound 结实的,坚固的spark erosion 火花蚀刻spindle 主轴spline 花键split 侧向分型,分型spool 线轴springback 反弹spring-loaded 装弹簧的sprue bush 主流道衬套sprue puller 浇道拉杆square 使成方形Servomechanism Laboratoies 伺服机构实验室stage 阶段standardisation 标准化startling 令人吃惊的steadily 稳定地step-by-step 逐步stickiness 粘性stiffness 刚度stock 毛坯,坯料storage tube display 储存管显示storage 储存器straightforward 直接的strain 应变strength 强度stress 压力,应力stress-strain 应力--应变stretch 伸展strike 冲击stringent 严厉的stripper 推板stroke 冲程,行程structrural build-up 结构上形成的sub-base 垫板subject 使受到submerge 淹没subsequent 后来的subsequently 后来,随后substantial 实质的substitute 代替,替换subtract 减,减去suitable 合适的,适当的suitably 合适地sunk 下沉,下陷superior 上好的susceptible 易受影响的sweep away 扫过symmetrical 对称的synchronize 同步,同时发生tactile 触觉的,有触觉的tailstock 尾架tapered 锥形的tapping 攻丝technique 技术tempering 回火tendency 趋向,倾向tensile 拉力的,可拉伸的tension 拉紧,张紧terminal 终端机terminology 术语,用辞theoretically 理论地thereby 因此,从而thermoplastic 热塑性的thermoplastic 热塑性塑料thermoset 热固性thoroughly 十分地,彻底地thread pitch 螺距thread 螺纹thrown up 推上tilt 倾斜,翘起tolerance 公差two-plate mould 双板式注射模tong 火钳tonnage 吨位,总吨数tool point 刀锋tool room 工具车间toolholder 刀夹,工具柄toolmaker 模具制造者toolpost grinder 工具磨床toolpost 刀架torsional 扭转的toughness 韧性trace 追踪transverse 横向的tray 盘,盘子,蝶treatment 处理tremendous 惊人的,巨大的trend 趋势trigger stop 始用挡料销tungsten 钨turning 车削twist 扭曲,扭转tracer-controlled milling machine 仿形铣床ultimately 终于undercut moulding 侧向分型模undercut 侧向分型undercut 底切underfeed 底部进料的undergo 经受underside 下面,下侧undue 不适当的,过度的uniform 统一的,一致的utilize 利用Utopian 乌托邦的,理想化的valve 阀vaporize 汽化vaporize (使)蒸发variation 变化various 不同的,各种的vector feedrate computation 向量进刀速率计算vee 字形velocity 速度versatile 多才多艺的,万用的vertical 垂直的via prep经,通过vicinity 附近viewpoint 观点wander 偏离方向warp 翘曲washer 垫圈wear 磨损well line 结合线whereupon 于是winding 绕,卷with respect to 相对于withstand 经受,经得起work 工件workstage 工序wrinkle 皱纹使皱yield 生产zoom 图象电子放大。
注塑模具毕业设计外文翻译--立体光照成型的注塑模具工艺的综合模拟
附录2Integrated simulation of the injection molding process withstereolithography moldsAbstract Functional parts are needed for design verification testing, field trials, customer evaluation, and production planning. By eliminating multiple steps, the creation of the injection mold directly by a rapid prototyping (RP) process holds the best promise of reducing the time and cost needed to mold low-volume quantities of parts. The potential of this integration of injection molding with RP has been demonstrated many times. What is missing is the fundamental understanding of how the modifications to the mold material and RP manufacturing process impact both the mold design and the injection molding process. In addition, numerical simulation techniques have now become helpful tools of mold designers and process engineers for traditional injection molding. But all current simulation packages for conventional injection molding are no longer applicable to this new type of injection molds, mainly because the property of the mold material changes greatly. In this paper, an integrated approach to accomplish a numerical simulation of injection molding into rapid-prototyped molds is established and a corresponding simulation system is developed. Comparisons with experimental results are employed for verification, which show that the present scheme is well suited to handle RP fabricated stereolithography (SL) molds.Keywords Injection molding Numerical simulation Rapid prototyping1 IntroductionIn injection molding, the polymer melt at high temperature is injected into the mold under high pressure [1]. Thus, the mold material needs to have thermal and mechanical properties capable of withstanding the temperatures and pressures of the molding cycle. The focus of many studies has been to create theinjection mold directly by a rapid prototyping (RP) process. By eliminating multiple steps, this method of tooling holds the best promise of reducing the time and cost needed to create low-volume quantities of parts in a production material. The potential of integrating injection molding with RP technologies has been demonstrated many times. The properties of RP molds are very different from those of traditional metal molds. The key differences are the properties of thermal conductivity and elastic modulus (rigidity). For example, the polymers used in RP-fabricated stereolithography (SL) molds have a thermal conductivity that is less than onethousandth that of an aluminum tool. In using RP technologies to create molds, the entire mold design and injection-molding process parameters need to be modified and optimized from traditional methodologies due to the completely different tool material. However, there is still not a fundamen tal understanding of how the modifications t o the mold tooling method and material impact both the mold design and the injection molding process parameters. One cannot obtain reasonable results by simply changing a few material properties in current models. Also, using traditional approaches when making actual parts may be generating sub-optimal results. So there is a dire need to study the interaction between the rapid tooling (RT) process and material and injection molding, so as to establish the mold design criteria and techniques for an RT-oriented injection molding process.In addition, computer simulation is an effective approach for predicting the quality of molded parts. Commercially available simulation packages of the traditional injection molding process have now become routine tools of the mold designer and process engineer [2]. Unfortunately, current simulation programs for conventional injection molding are no longer applicable to RP molds, because of the dramatically dissimilar tool material. For instance, in using the existing simulation software with aluminum and SL molds and comparing with experimental results, though the simulation values of part distortion are reasonable for the aluminum mold, results are unacceptable, with the error exceeding 50%. The distortion during injection molding is due to shrinkage and warpage of the plastic part, as well as the mold. For ordinarily molds, the main factor is the shrinkage and warpage of the plastic part, which is modeled accurately in current simulations. But for RP molds, the distortion of the mold has potentially more influence, which have been neglected in current models. For instance, [3] used a simple three-step simulation process to consider the mold distortion, which had too much deviation.In this paper, based on the above analysis, a new simulation system for RP molds is developed. The proposed system focuses on predicting part distortion, which is dominating defect in RP-molded parts. The developed simulation can be applied as an evaluation tool for RP mold design and process optimization. Our simula tion system is verified by an experimental example.Although many materials are available for use in RP technologies, we concentrate on using stereolithography (SL), the original RP technology, to create polymer molds. The SL process uses photopolymer and laser energy to build a part layer by layer. Using SL takes advantage of both the commercial dominance of SL in the RP industry and the subsequent expertise base that has been developed for creating accurate, high-quality parts. Until recently, SL was primarily used to create physical models for visual inspection and form-fit studies with very limited func-tional applications. However, the newer generation stereolithographic photopolymers have improved dimensional, mechanical and thermal properties making it possible to use them for actual functional molds.2 Integrated simulation of the molding process2.1 MethodologyIn order to simulate the use of an SL mold in the injection molding process, an iterative method is proposed. Different software modules have been developed and used to accomplish this task. The main assumption is that temperature and load boundary conditions cause significant distortions in the SL mold. The simulation steps are as follows:1The part geometry is modeled as a solid model, which is translated to a file readable by the flow analysis package.2Simulate the mold-filling process of the melt into a pho topolymer mold, which will output the resulting temperature and pressure profiles.3Structural analysis is then performed on the photopolymer mold model using the thermal and load boundary conditions obtained from the previous step, which calculates the distortion that the mold undergo during the injection process.4If the distortion of the mold converges, move to the next step. Otherwise, the distorted mold cavity is then modeled (changes in the dimensions of the cavity after distortion), and returns to the second step to simulate the melt injection into the distorted mold.5The shrinkage and warpage simulation of the injection molded part is then applied, which calculates the final distor tions of the molded part.In above simulation flow, there are three basic simulation mod ules.2. 2 Filling simulation of the melt2.2.1 Mathematical modelingIn order to simulate the use of an SL mold in the injection molding process, an iterative method is proposed. Different software modules have been developed and used to accomplish this task. The main assumption is that temperature and load boundary conditions cause significant distortions in the SL mold. The simulation steps are as follows:1. The part geometry is modeled as a solid model, which is translated to a file readable by the flow analysis package.2. Simulate the mold-filling process of the melt into a photopolymer mold, which will output the resulting temperature and pressure profiles.3. Structural analysis is then performed on the photopolymer mold model using the thermal and load boundary conditions obtained from the previous step, which calculates the distortion that the mold undergo during the injection process.4. If the distortion of the mold converges, move to the next step. Otherwise, the distorted mold cavity is then modeled (changes in the dimensions of the cavity after distortion), and returns to the second step to simulate the melt injection into the distorted mold.5. The shrinkage and warpage simulation of the injection molded part is then applied, which calculates the final distortions of the molded part.In above simulation flow, there are three basic simulation modules.2.2 Filling simulation of the melt2.2.1 Mathematical modelingComputer simulation techniques have had success in predicting filling behavior in extremely complicated geometries. However, most of the current numerical implementation is based on a hybrid finite-element/finite-difference solution with the middleplane model. The application process of simulation packages based on this model is illustrated in Fig. 2-1. However, unlike the surface/solid model in mold-design CAD systems, the so-called middle-plane (as shown in Fig. 2-1b) is an imaginary arbitrary planar geometry at the middle of the cavity in the gap-wise direction, which should bring about great inconvenience in applications. For example, surface models are commonly used in current RP systems (generally STL file format), so secondary modeling is unavoidable when using simulation packages because the models in the RP and simulation systems are different. Considering these defects, the surface model of the cavity is introduced as datum planes in the simulation, instead of the middle-plane.According to the previous investigations [4–6], fillinggoverning equations for the flow and temperature field can be written as:where x, y are the planar coordinates in the middle-plane, and z is the gap-wise coordinate; u, v,w are the velocity components in the x, y, z directions; u, v are the average whole-gap thicknesses; and η, ρ,CP (T), K(T) represent viscosity, density, specific heat and thermal conductivity of polymer melt, respectively.Fig.2-1 a–d. Schematic procedure of the simulation with middle-plane model. a The 3-D surface model b The middle-plane model c The meshed middle-plane model d The display of the simulation result In addition, boundary conditions in the gap-wise direction can be defined as:where TW is the constant wall temperature (shown in Fig. 2a).Combining Eqs. 1–4 with Eqs. 5–6, it follows that the distributions of the u, v, T, P at z coordinates should be symmetrical, with the mirror axis being z = 0, and consequently the u, v averaged in half-gap thickness is equal to that averaged in wholegap thickness. Based on this characteristic, we can divide the whole cavity into two equal parts in the gap-wise direction, as described by Part I and Part II in Fig. 2b. At the same time, triangular finite elements are generated in the surface(s) of the cavity (at z = 0 in Fig. 2b), instead of the middle-plane (at z = 0 in Fig. 2a). Accordingly, finite-difference increments in the gapwise direction are employed only in the inside of the surface(s) (wall to middle/center-line), which, in Fig. 2b, means from z = 0 to z = b. This is single-sided instead of two-sided with respect to the middle-plane (i.e. from the middle-line to two walls). In addition, the coordinate system is changed from Fig. 2a to Fig. 2b to alter the finite-element/finite-difference scheme, as shown in Fig. 2b. With the above adjustment, governing equations are still Eqs. 1–4. However, the original boundary conditions inthe gapwise direction are rewritten as:Meanwhile, additional boundary conditions must be employed at z = b in order to keep the flows at the juncture of the two parts at the same section coordinate [7]:where subscripts I, II represent the parameters of Part I and Part II, respectively, and Cm-I and Cm-II indicate the moving free melt-fronts of the surfaces of the divided two parts in the filling stage.It should be noted that, unlike conditions Eqs. 7 and 8, ensuring conditions Eqs. 9 and 10 are upheld in numerical implementations becomes more difficult due to the following reasons:1. The surfaces at the same section have been meshed respectively, which leads to a distinctive pattern of finite elements at the same section. Thus, an interpolation operation should be employed for u, v, T, P during the comparison between the two parts at the juncture.2. Because the two parts have respective flow fields with respect to the nodes at point A and point C (as shown in Fig. 2b) at the same section, it is possible to have either both filled or one filled (and one empty). These two cases should be handled separately, averaging the operation for the former, whereas assigning operation for the latter.3. It follows that a small difference between the melt-fronts is permissible. That allowance can be implemented by time allowance control or preferable location allowance control of the melt-front nodes.4. The boundaries of the flow field expand by each melt-front advancement, so it is necessary to check the condition Eq. 10 after each change in the melt-front.5. In view of above-mentioned analysis, the physical parameters at the nodes of the same section should be compared and adjusted, so the information describing finite elements of the same section should be prepared before simulation, that is, the matching operation among the elements should be preformed.Fig. 2a,b. Illustrative of boundary conditions in the gap-wise direction a of the middle-plane model b of thesurface model2.2.2 Numerical implementationPressure field. In modeling viscosity η, which is a function of shear rate, temperature and pressure of melt, the shear-thinning behavior can be well represented by a cross-type model such as:where n corresponds to the power-law index, and τ∗ characterizes the shear stress level of the transition region between the Newtonian and power-law asymptotic limits. In terms of an Arrhenius-type temperature sensitivity and exponential pressure dependence, η0(T, P) can be represented with reasonable accuracy as follows:Equations 11 and 12 constitute a five-constant (n, τ∗, B, Tb, β) representation for viscosity. The shear rate for viscosity calculation is obtained by:Based on the above, we can infer the following filling pressure equation from the governing Eqs. 1–4:where S is calculated by S = b0/(b−z)2η d z. Applying the Galerkin method, the pressure finite-element equation is deduced as:where l_ traverses all elements, including node N, and where I and j represent the local node number in element l_ corresponding to the node number N and N_ in the whole, respectively. The D(l_) ij is calculated as follows:where A(l_) represents triangular finite elements, and L(l_) i is the pressure trial function in finite elements.Temperature field. To determine the temperature profile across the gap, each triangular finite element at the surface is further divided into NZ layers for the finite-difference grid.The left item of the energy equation (Eq. 4) can be expressed as:where TN, j,t represents the temperature of the j layer of node N at time t.The heat conduction item is calculated by:where l traverses all elements, including node N, and i and j represent the local node number in element l corresponding to the node number N and N_ in the whole, respectively.The heat convection item is calculated by:For viscous heat, it follows that:Substituting Eqs. 17–20 into the energy equation (Eq. 4), the temperature equation becomes:2.3 Structural analysis of the moldThe purpose of structural analysis is to predict the deformation occurring in the photopolymer mold due to the thermal and mechanical loads of the filling process. This model is based on a three-dimensional thermoelastic boundary element method (BEM). The BEM is ideally suited for this application because only the deformation of the mold surfaces is of interest. Moreover, the BEM has an advantage over other techniques in that computing effort is not wasted on calculating deformation within the mold.The stresses resulting from the process loads are well within the elastic range of the mold material. Therefore, the mold deformation model is based on a thermoelastic formulation. The thermal and mechanical properties of the mold are assumed to be isotropic and temperature independent.Although the process is cyclic, time-averaged values of temperature and heat flux are used for calculating the mold deformation. Typically, transient temperature variations within a mold have been restricted to regions local to the cavity surface and the nozzle tip [8]. The transients decay sharply with distance from the cavity surface and generally little variation is observed beyond distances as small as 2.5 mm. This suggests that the contribution from the transients to the deformation at the mold block interface is small, and therefore it is reasonable to neglect the transient effects. The steady state temperature field satisfies Laplace’s equation 2T = 0 and the time-averaged boundary conditions. The boundary conditions on the mold surfaces are described in detail by Tang et al. [9]. As for the mechanical boundary conditions, the cavity surface is subjected to the melt pressure, the surfaces of the mold connected to the worktable are fixed in space, and other external surfaces are assumed to be stress free.The derivation of the thermoelastic boundary integral formulation is well known [10]. It is given by:where uk, pk and T are the displacement, traction and temperature,α, ν represent the thermal expansion coefficient and Poisson’s ratio of the material, and r = |y−x|. clk(x) is the surfacecoefficient which depends on the local geometry at x, the orientation of the coordinate frame and Poisson’s ratio for the domain [11]. The fundamental displacement ˜ulk at a point y in the xk direction, in a three-dimensional infinite isotropic elastic domain, results from a unit load concentrated at a point x acting in the xl direction and is of the form:where δlk is the Kronecker delta function and μ is the shear modulus of the mold material.The fundamental traction ˜plk , measured at the point y on a surface with unit normal n, is:Discretizing the surface of the mold into a total of N elements transforms Eq. 22 to:where Γn refers to the n th surface element on the domain.Substituting the appropriate linear shape functions into Eq. 25, the linear boundary element formulation for the mold deformation model is obtained. The equation is applied at each node on the discretized mold surface, thus giving a system of 3N linear equations, where N is the total number of nodes. Each node has eight associated quantities: three components of displacement, three components of traction, a temperature and a heat flux. The steady state thermal model supplies temperature and flux values as known quantities for each node, and of the remaining six quantities, three must be specified. Moreover, the displacement values specified at a certain number of nodes must eliminate the possibility of a rigid-body motion or rigid-body rotation to ensure a non-singular system of equations. The resulting system of equations is assembled into a integrated matrix, which is solved with an iterative solver.2.4 Shrinkage and warpage simulation of the molded partInternal stresses in injection-molded components are the principal cause of shrinkage and warpage. These residual stresses are mainly frozen-in thermal stresses due to inhomogeneous cooling, when surface layers stiffen sooner than the core region, as in free quenching. Based onthe assumption of the linear thermo-elastic and linear thermo-viscoelastic compressible behavior of the polymeric materials, shrinkage and warpage are obtained implicitly using displacement formulations, and the governing equations can be solved numerically using a finite element method.With the basic assumptions of injection molding [12], the components of stress and strain are given by:The deviatoric components of stress and strain, respectively, are given byUsing a similar approach developed by Lee and Rogers [13] for predicting the residual stresses in the tempering of glass, an integral form of the viscoelastic constitutive relationships is used, and the in-plane stresses can be related to the strains by the following equation:Where G1 is the relaxation shear modulus of the material. The dilatational stresses can be related to the strain as follows:Where K is the relaxation bulk modulus of the material, and the definition of α and Θ is: If α(t) = α0, applying Eq. 27 to Eq. 29 results in:Similarly, applying Eq. 31 to Eq. 28 and eliminating strain εxx(z, t) results in:Employing a Laplace transform to Eq. 32, the auxiliary modulus R(ξ) is given by:Using the above constitutive equation (Eq. 33) and simplified forms of the stresses and strains in the mold, the formulation of the residual stress of the injection molded part during the cooling stage is obtain by:Equation 34 can be solved through the application of trapezoidal quadrature. Due to the rapid initial change in the material time, a quasi-numerical procedure is employed for evaluating the integral item. The auxiliary modulus is evaluated numerically by the trapezoidal rule.For warpage analysis, nodal displacements and curvatures for shell elements are expressed as:where [k] is the element stiffness matrix, [Be] is the derivative operator matrix, {d} is the displacements, and {re} is the element load vector which can be evaluated by:The use of a full three-dimensional FEM analysis can achieve accurate warpage results, however, it is cumbersome when the shape of the part is very complicated. In this paper, a twodimensional FEM method, based on shell theory, was used because most injection-molded parts have a sheet-like geometry in which the thickness is much smaller than the other dimensions of the part. Therefore, the part can be regarded as an assembly of flat elements to predict warpage. Each three-node shell element is a combination of a constant strain triangular element (CST) and a discrete Kirchhoff triangular element (DKT), as shown in Fig. 3. Thus, the warpage can be separated into plane-stretching deformation of the CST and plate-bending deformation of the DKT, and correspondingly, the element stiffness matrix to describe warpage can also be divided into the stretching-stiffness matrix and bending-stiffness matrix.Fig. 3a–c. Deformation decomposition of shell element in the local coordinate system. a In-plane stretchingelement b Plate-bending element c Shell element3 Experimental validationTo assess the usefulness of the proposed model and developed program, verification is important. The distortions obtained from the simulation model are compared to the ones from SL injection molding experiments whose data is presented in the literature [8]. A common injection molded part with the dimensions of 36×36×6 mm is considered in the experiment, as shown in Fig. 4. The thickness dimensions of the thin walls and rib are both 1.5 mm; and polypropylene was used as the injection material. The injection machine was a production level ARGURY Hydronica 320-210-750 with the following process parameters: a melt temperature of 250 ◦C; an ambient temperature of 30 ◦C; an injection pressure of 13.79 MPa; an injection time of 3 s; and a cooling time of 48 s. The SL material used, Dupont SOMOSTM 6110 resin, has the ability to resist temperatures of up to 300 ◦C temperatures. As mentioned above, thermal conductivity of the mold is a major factor that differentiates between an SL and a traditional mold. Poor heat transfer in the mold would produce a non-uniform temperature distribution, thus causing warpage that distorts the completed parts. For an SL mold, a longer cycle time would be expected. The method of using a thin shell SL mold backed with a higher thermal conductivity metal (aluminum) was selected to increase thermal conductivity of the SL mold.Fig. 4. Experimental cavity modelFig. 5. A comparison of the distortion variation in the X direction for different thermal conductivity; where “Experimental”, “present”, “three-step”, and “conventional” mean the results of the experimental, the presented simulation, the three-step simulation process and the conventional injection molding simulation, respectively.Fig. 6. Comparison of the distortion variation in the Y direction for different thermal conductivitiesFig. 7. Comparison of the distortion variation in the Z direction for different thermal conductivitiesFig. 8. Comparison of the twist variation for different thermal conductivities For this part, distortion includes the displacements in three directions and the twist (the difference in angle between two initially parallel edges). The validation results are shown in Fig.5 to Fig. 8. These figures also include the distortion values predicted by conventional injection molding simulation and the three-step model reported in [3].4 ConclusionsIn this paper, an integrated model to accomplish the numerical simulation of injection molding into rapid-prototyped molds is established and a corresponding simulation system is developed. For verification, an experiment is also carried out with an RPfabricated SL mold.It is seen that a conventional simulation using current injection molding software breaks down for a photopolymer mold. It is assumed that this is due to the distortion in the mold caused by the temperature and load conditions of injection. The three-step approach also has much deviation. The developed model gives results closer to experimental.Improvement in thermal conductivity of the photopolymer significantly increases part quality. Since the effect of temperature seems to be more dominant than that of pressure (load), an improvement in the thermal conductivity of the photopolymer can improve the part quality significantly.Rapid Prototyping (RP) is a technology makes it possible to manufacture prototypes quickly and inexpensively, regardless of their complexity. Rapid Tooling (RT) is the next step in RP’s steady progress and much work is being done to obtain more accurate tools to define the parameters of the process. Existing simulation tools can not provide the researcher with a useful means of studying relative changes. An integrated model, such as the one presented in this paper, is necessary to obtain accurate predictions of the actual quality of final parts. In the future, we expect to see this work expanded to develop simulations program for injection into RP molds manufactured by other RT processes.References1. Wang KK (1980) System approach to injection molding process. Polym-Plast Technol Eng 14(1):75–93.2. Shelesh-Nezhad K, Siores E (1997) Intelligent system for plastic injection molding process design. J Mater Process Technol 63(1–3):458–462.3. Aluru R, Keefe M, Advani S (2001) Simulation of injection molding into rapid-prototyped molds. Rapid Prototyping J 7(1):42–51.4. Shen SF (1984) Simulation of polymeric flows in the injection molding process. Int J Numer Methods Fluids 4(2):171–184.5. Agassant JF, Alles H, Philipon S, Vincent M (1988) Experimental and theoretical study of the injection molding of thermoplastic materials. Polym Eng Sci 28(7):460–468.6. Chiang HH, Hieber CA, Wang KK (1991) A unified simulation of the filling and post-filling stages in injection molding. Part I: formulation. Polym Eng Sci 31(2):116–124.7. Zhou H, Li D (2001) A numerical simulation of the filling stage in injection molding based on a surface model. Adv Polym Technol 20(2):125–131.8. Himasekhar K, Lottey J, Wang KK (1992) CAE of mold cooling in injection molding using a three-dimensional numerical simulation. J EngInd Trans ASME 114(2):213–221.9. Tang LQ, Pochiraju K, Chassapis C, Manoochehri S (1998) Computeraided optimization approach for the design of injection mold cooling systems. J Mech Des, Trans ASME 120(2):165–174.10. Rizzo FJ, Shippy DJ (1977) An advanced boundary integral equation method for three-dimensional thermoelasticity. Int J Numer Methods Eng 11:1753–1768.11. Hartmann F (1980) Computing the C-matrix in non-smooth boundary points. In: New developments in boundary element methods, CML Publications, Southampton, pp 367–379.12. Chen X, Lama YC, Li DQ (2000) Analysis of thermal residual stress in plastic injection molding. J Mater Process Technol 101(1):275–280.13. Lee EH, Rogers TG (1960) Solution of viscoelastic stress analysis problems using measured creep or relaxation function. J Appl Mech 30(1):127–134.14. Li Y (1997) Studies in direct tooling using stereolithography. Dissertation, University of Delaware, Newark, DE..。
模具毕业设计英译汉(Injection_molding)
模具毕业设计英译汉(Injection_molding)Injection moldingInjection molding (British English: moulding) is a manufacturing process for producing parts from both thermoplastic and thermosetting plastic materials. Material is fed into a heated barrel, mixed, and forced into a mold cavity where it cools and hardens to the configuration of the mold cavity.After a product is designed, usually by an industrial designer or an engineer, molds are made by a moldmaker (or toolmaker) from metal, usually either steel or aluminum, and precision-machined to form the features of the desired part. Injection molding is widely used for manufacturing a variety of parts, from the smallest component to entire body panels of cars.ApplicationsInjection molding is used to create many things such as wire spools, packaging, bottle caps, automotive dashboards, pocket combs, and most other plastic products available today. Injection molding is the most common method of part manufacturing. It is ideal for producing high volumes of the same object.Some advantages of injection molding are high production rates, repeatable high tolerances, the ability to use a wide range of materials, low labor cost, minimal scrap losses, and little need to finish parts after molding. Some disadvantages of this process are expensive equipment investment, potentially high running costs, and the need to design moldable parts.EquipmentPaper clip mold opened in molding machine; the nozzle is visible at rightMain article: Injection molding machineInjection molding machines consist of a material hopper, an injection ram or screw-type plunger, and a heating unit. They are also known as presses, they hold the molds in which the components are shaped. Presses are rated by tonnage, which expresses the amount of clamping force that the machine can exert. This force keeps the mold closed during the injection process. Tonnage can vary from less than 5 tons to 6000 tons, with the higher figures used in comparatively few manufacturing operations. The total clamp force needed is determined by the projected area of the part being molded. This projected area is multiplied by a clamp force of from 2 to 8 tons for each square inch of the projected areas. As a rule of thumb, 4 or 5 tons/in2 can be used for most products. If the plastic material is very stiff, it will require more injection pressure to fill the mold, thus more clamp tonnage to hold the mold closed. The required force can also be determined by the material used and the size of the part, larger parts require higher clamping force.MoldMold or die are the common terms used to describe the tooling used to produce plastic parts in molding.Since molds have been expensive to manufacture, they were usually only used in mass production where thousands of parts were being produced. Typical molds are constructed from hardened steel, pre-hardened steel, aluminum, and/or beryllium-copper alloy. The choice of material to build a mold from is primarily one of economics; in general, steel molds cost more to construct, but their longer lifespan will offset the higher initial cost over a higher number of parts made before wearing out. Pre-hardened steel molds are less wear-resistant and are used for lower volume requirements or larger components. The typicalsteel hardness is 38-45 on the Rockwell-C scale. Hardened steel molds are heat treated after machining. These are by far the superior in terms of wear resistance and lifespan. Typical hardness ranges between 50 and 60 Rockwell-C (HRC). Aluminum molds can cost substantially less, and, when designed and machined with modern computerized equipment, can be economical for molding tens or even hundreds of thousands of parts. Beryllium copper is used in areas of the mold that require fast heat removal or areas that see the most shear heat generated. The molds can be manufactured either by CNC machining or by using Electrical Discharge Machining processes.Mold DesignStandard two plates tooling –core and cavity are inserts in a mold base – "Family mold" of 5 different partsThe mold consists of two primary components, the injection mold (A plate) and the ejector mold (B plate). Plastic resin enters the mold through a sprue in the injection mold, the sprue bushing is to seal tightly against the nozzle of the injection barrel of the molding machine and to allow molten plastic to flow from the barrel into the mold, also known as cavity The sprue bushing directs the molten plastic to the cavity images through channels that are machined into the faces of the A and B plates. These channels allow plastic to run along them, so they are referred to as runners.The molten plastic flows through the runner and enters one or more specialized gates and into the cavity geometry to form the desired part.The amount of resin required to fill the sprue, runner and cavities of a mold is a shot. Trapped air in the mold can escape through air vents that are ground into the parting line of the mold. If the trapped air is not allowed to escape, it is compressedby the pressure of the incoming material and is squeezed into the corners of the cavity, where it prevents filling and causes other defects as well. The air can become so compressed that it ignites and burns the surrounding plastic material. To allow for removal of the molded part from the mold, the mold features must not overhang one another in the direction that the mold opens, unless parts of the mold are designed to move from between such overhangs when the mold opens (utilizing components called Lifters).Sides of the part that appear parallel with the direction of draw (The axis of the cored position (hole) or insert is parallel to the up and down movement of the mold as it opens and closes)are typically angled slightly with (draft) to ease release of the part from the mold. Insufficient draft can cause deformation or damage. The draft required for mold release is primarily dependent on the depth of the cavity: the deeper the cavity, the more draft necessary. Shrinkage must also be taken into account when determining the draft required.If the skin is too thin, then the molded part will tend to shrink onto the cores that form them while cooling, and cling to those cores or part may warp, twist, blister or crack when the cavity is pulled away. The mold is usually designed so that the moldedpart reliably remains on the ejector (B) side of the mold when it opens, and draws the runner and the sprue out of the (A) side along with the parts. The part then falls freely when ejected from the (B) side. Tunnel gates, also known as submarine or mold gate, is located below the parting line or mold surface. The opening is machined into the surface of the mold on the parting line. The molded part is cut (by the mold) from the runner system on ejection from the mold. Ejector pins, also known as knockout pin,is a circular pin placed in either half of the mold (usually the ejector half), which pushes the finished molded product, or runner system out of a mold.The standard method of cooling is passing a coolant (usually water) through a series of holes drilled through the mold plates and connected by hoses to form a continueous pathway. The coolant absorbs heat from the mold (which has absorbed heat from the hot plastic) and keeps the mold at a proper temperature to solidify the plastic at the most efficient rate.To ease maintenance and venting, cavities and cores are divided into pieces, called inserts, and sub-assemblies, also called inserts, blocks, or chase blocks. By substituting interchangeable inserts, one mold may make several variations of the same part.More complex parts are formed using more complex molds. These may have sections called slides, that move into a cavity perpendicular to the draw direction, to form overhanging part features. When the mold is opened, the slides are pulled away from the plastic part by using st ationary “angle pins” on the stationary mold half. These pins enter a slot in the slides and cause the slides to move backward when the moving half of the mold opens. The part is then ejected and the mold closes. The closing action of the mold causes the slides to move forward along the angle pins.Some molds allow previously molded parts to be reinserted to allow a new plastic layer to form around the first part. This is often referred to as overmolding. This system can allow for production of one-piece tires and wheels.2-shot or multi-shot molds are designed to "overmold" within a single molding cycle and must be processed on specialized injection molding machines with two or moreinjection units. This process is actually an injection molding process performed twice. In the first step, the base color material is molded into a basic shape. Then the second material is injection-molded into the remaining open spaces. That space is then filled during the second injection step with a material of a different color.A mold can produce several copies of the same parts in a single "shot". The number of "impressions" in the mold of that part is often incorrectly referred to as cavitation. A tool with one impression will often be called a single impression(cavity) mold.A mold with 2 or more cavities of the same parts will likely be referred to as multiple impression (cavity) mold.Some extremely high production volume molds (like those for bottle caps) can have over 128 cavities.In some cases multiple cavity tooling will mold a series of different parts in the same tool. Some toolmakers call these molds family molds as all the parts are related.Effects on the material propertiesThe mechanical properties of a part are usually little affected. Some parts can have internal stresses in them. This is one of the reasons why it's good to have uniform wall thickness when molding. One of the physical property changes is shrinkage. A permanent chemical property change is the material thermoset, which can't be remelted to be injected again.Tool MaterialsTool steel or beryllium-copper are often used. Mild steel, aluminum, nickel or epoxy are suitable only for prototype or very short production runs.Modern hard aluminum (7075 and 2024 alloys) with proper mold design, can easily make molds capable of 100,000 or more part life.Geometrical PossibilitiesThe most commonly used plastic molding process, injection molding, is used to create a large variety of products with different shapes and sizes. Most importantly, they can create products with complex geometry that many other processes cannot. There are a few precautions when designing something that willbe made using this process to reduce the risk of weak spots. First, streamline your product or keep the thickness relatively uniform. Second, try and keep your product between 2 to20 inches.The size of a part will depend on a number of factors (material, wall thickness, shape,process etc.). The initial raw material required may be measured in the form of granules, pellets or powders. Here are some ranges of the sizes.MachiningMolds are built through two main methods: standard machining and EDM. Standard Machining, in its conventional form, has historically been the method of building injection molds. With technological development, CNC machining became the predominant means of making more complex molds with more accurate mold details in less time than traditional methods.The electrical discharge machining (EDM) or spark erosion process has become widely used in mold making. As well as allowing the formation of shapes that are difficult to machine, the process allows pre-hardened molds to be shaped so that no heat treatment is required. Changes to a hardened mold by conventional drilling and milling normally require annealing to soften the mold, followed by heat treatment to harden it again. EDM is a simple process in which a shaped electrode, usuallymade of copper or graphite, is very slowly lowered onto the mold surface (over a period of many hours), which is immersed in paraffin oil. A voltage applied between tool and mold causes spark erosion of the mold surface in the inverse shape of the electrode.CostThe cost of manufacturing molds depends on a very large set of factors ranging from number of cavities, size of the parts (and therefore the mold), complexity of the pieces, expected tool longevity, surface finishes and many others. The initial cost is great, however the piece part cost is low, so with greater quantities the overall price decreases.Injection processSmall injection molder showing hopper, nozzle and die area With Injection Molding, granular plastic is fed by gravity from a hopper into a heated barrel. As the granules are slowly moved forward by a screw-type plunger, the plastic is forced into a heated chamber, where it is melted. As the plunger advances, the melted plastic is forced through a nozzle that rests against the mold, allowing it to enter the mold cavity through a gate and runner system. The mold remains cold so the plastic solidifies almost as soon as the mold is filled.Injection Molding CycleThe sequence of events during the injection mold of a plastic part is called the injection molding cycle. The cycle begins when the mold closes, followed by the injection of the polymer into the mold cavity. Once the cavity is filled, a holding pressure is maintained to compensate for material shrinkage. In the next step, the screw turns, feeding the next shot to the front screw.This causes the screw to retract as the next shot is prepared. Once thepart is sufficiently cool, the mold opens and the part is ejected.Molding trialWhen filling a new or unfamiliar mold for the first time, where shot size for that mold is unknown, a technician/tool setter usually starts with a small shot weight and fills gradually until the mold is 95 to 99% full. Once this is achieved a small amount of holding pressure will be applied and holding time increased until gate freeze off (solidification time) has occurred. Gate solidification time is an important as it determines cycle time, which itself is an important issue in the economics of the production process. Holding pressure is increased until the parts are free of sinks and part weight has been achieved. Once the parts are good enough and have passed any specific criteria, a setting sheet is produced for people to follow in the future. The method to setup an unknown mold the first time can be supported by installing cavity pressure sensors. Measuring the cavity pressure as a function of time can provide a good indication of the filling profile of the cavity. Once the equipment is set to successfully create the molded part, modern monitoring systems can save a reference curve of the cavity pressure. With that it is possible toreproduce the same part quality on another molding machine within a short setup time.Tolerances and SurfacesMolding tolerance is a specified allowance on the deviation in parameters such as dimensions, weights, shapes, or angles, etc. To maximize control in setting tolerances there is usually a minimum and maximum limit on thickness, based on the process used.Injection molding typically is capable of tolerances equivalent to an IT Grade of about 9–14. The possible toleranceof a thermoplastic or a thermoset is ±0.008 to ±0.002 inches. Surface finishes of two to four microinches or better are can be obtained. Rough or pebbled surfaces are also possible.Lubrication and CoolingObviously, the mold must be cooled in order for the production to take place. Because of the heat capacity, inexpensiveness, and availability of water, water is used as the primary cooling agent. To cool the mold, water can be channeled through the mold to account for quick cooling times. Usually a colder mold is more efficient because this allows for faster cycle times. However, this is not always true because crystalline materials require the opposite: a warmer mold and lengthier cycle time.InsertsMetal inserts can be also be injection molded into the workpiece. For large volume parts the inserts are placed in the mold using automated machinery. An advantage of using automated components is that the smaller size of parts allows a mobile inspection system that can be used to examine multiple parts in a decreased amount of time. In addition to mounting inspection systems on automated components, multiple axial robots are also capable of removing parts from the mold and place them in latter systems that can be used to ensure quality of multiple parameters. The ability of automated components to decrease the cycle time of the processes allows for a greater output of quality parts.Specific instances of this increased efficiency include the removal of parts from the mold immediately after the parts are created and use in conjunction with vision systems. The removal of parts is achieved by using robots to grip the partonce it has become free from the mold after in ejector pins have been raised. The robot then moves these parts into either a holding location or directly onto an inspection system, depending on the type of product and the general layout of the rest of the manufacturer's production facility. Visions systems mounted on robots are also an advancement that has greatly changed the way that quality control is performed in insert molded parts. A mobile robot is able to more precisely determine the accuracy of the metal component and inspect more locations in the same amount of time as a human inspector.注塑成型注射制模(Injection moldin)是一种生产由热塑性塑料或热固性塑料所构成的部件的过程。
模具设计外文翻译---塑料成型过程.
外文翻译原文Plastics forming processesThere is a wide range of processing methods that may be used for plastics. Nevertheless, they all involve three or four basic stages: softening, shaping, solidifying and cooling of the moulds (for thermoplastics only). Common materials for moulding processes are thermoplastics and thermoset polymers. Principal methods of processing thermoplastics include extols ion, blow moulding, rotational moulding, thermoforming and injection moulding; but as for thermosets, compression, transfer and reaction injection moulding are frequently used.1 ExtrusionExtrusion is one of the most important forming processes for the reason that pellets, which are used for many other moulding processes, are normally produced by this process. In fact, some moulding processes are post-extrusion operations, such as blow moulding and thermoform moulding. Extnlsion is basically a process of continuously shaping a fluid polymer through the orifice of a die, and subsequently solidifying it into a product of a uniform cross-section. An extruding machine may have one or two screws, or no screw (screwless). Single-screw extruders, as seen in Figure 1, are the most commonly used machines. Screwless (ram) extruders allow a precise control of the melt flow rate and are gaining popularity. They are particularly suited for high viscosity. In recent years, there has been a steady increase in the use of twin screw extruders. These machines permit a wider ranger of possibilities in terms of output rates, mixing efficiency and heat generation. They are, however, considerably more mon extrusion products include filaments of circular cross-section, profiles of irregular cross-section, axisymmetric tubes and pipes, and flat products such as films or sheets. Almost all types of intricate cross-sectional shapes with large lengths are made by extrusion moulding, which many other discrete forming processes, such as compression, transfer and injection moulding, are incapable of producing.FIGURE 1.Single-screw extruder.2 Blow mouldingThis process begins with the preparation of a soft, extruded and preformed thermoplastic tube over a core pin.As the mould halves close, air pressure inflates the thinwalled preform and forces it outwards against the mould sides. Figure 2 shows the process at two stages. The preform can be made by either extras ion or injection. Blow moulds are subjected to moderate pressures and clamping forces, compared to injection moulds. Thus, they can be made of a light material such as aluminmm, which has advantages of light weight and high heat conductivity.Blown-ware containers are commonly used for packaging beverage and other fluid food, e.g. narrow neck plastic bottles for mineral water, milk, alcoholic beverage and carbonated beverages. Other non-food products packed in the blown-ware containers include cosmetics, pharmaceuticals, paint and powder products. Blow moulding is also used to produce some huge products in size, such as shipping drums and stationary storage tanks whose volumes may reach as high as 10 000 litres [5]. These tanks are used for underground fuel storage and septic tanks.Stage 1: Preform extrusion Stage 2: BlowingFIGURE 2.Extrusion blow moulding3 Rotational mouldingLike blow moulding, rotational moulding is also used to produce hollow plastic articles, though the principles in each method differ a lot. During the process, a carefully weighed charge of plastic powder is placed in one half of a metal mould. The mould halves are then clamped together and heated on an oven. When heated, the mould rotates about two axes at right angles to each other. After a time the plastics will be sufficiently softened to form a homogeneous layer on the surface of the mould. The process is attractive for a number of reasons. Firstly, as it is a low-pressure process, the moulds are relatively simple and inexpensive. Secondly, the product is virtually strata-free. Thirdly, a uniform thickness can be easily achieved. Finally, it is possible to introduce reinforcement into the products, and their surface can be textured as desired. However, the cycle times are longer compared to blow or injection moulding. The mould-handling device, capable of imparting double rotations, is the central element of rotational moulding equipment. There are two major types of equipment: shuttle cart system, as shown Figure 3, and swing/rotary arm system. Rotational moulding is good at producing very large, thick-walled articles which could not be produced economically by any other processes. The largest capacity of arotational-moulding made tank is recorded at about 75 000 litres [4].FIGURE 3.Shuttle cart rotational moulding.The Institution of Professional Engineers New Zealand4 Compression mouldingCompression moulding is often used to produce articles from thermoset materials, though it can also be used for thermoplastics. The moulding operation used for thermosets is illustrated in Figure 4. A large number of compression moulded thermoset products can be found in electrical and electronic applications. Glass-fibre reinforcement can be easily added to meet the heat resistance requirement. However, the limitation with this process is that the product has to be simple in shape and without thin walls or fragile inserts. Numerous rubber products are compression moulded. A useful feature of it is its ability to have metal inserts that form strong bonds with the product and are often used to attach the product to structures. Tyres are the most common products made by compression moulding.FIGURE pression moulding.5 Transfer mouldingTransfer moulding is similar to compression moulding except that, instead of the moulding material being pressurised in the cavity, it is pressurised in a separate chamber and then forced through an opening and into a closed mould cavity. The advantage of transfer moulding is that thepreheating of the material injected through a narrow orifice improves the temperature distribution in the material and hence accelerates the cross-linking reaction in thermosets. As a result the cycle time is reduced and there is less distortion in the product. The improved flow of material also means that more intricate shapes can be produced. Parts with fragile inserts like electric appliance parts, electronic components and connectors that may enclose coils, integrated circuits, and plugs can also be easily made.6 ThermoformingSheet thermoforming was developed in the 1950s. The limitations such as poor wall thickness distribution and large peripheral waste restricted its use to simple packaging applications. In recent years, however, there have been major advances in machine design and materials, which have resulted in a wide range of products being made by thermoforming. There are three types of thermoforming processes (Figure 5): vacuum moulding, air pressure moulding, and mechanical moulding.The moulds, which are not subjected to high pressure, are often made from cast or machined alumininm for small and medium sizes, and they do not require a good surface finish. The product surface quality is largely dependent upon that of the sheet material.Products made by thermoforming can be small as well as large. Smaller products are made in high output machines, using multi-cavity moulds. Such products are often found in the food industry and medical applications, for example, jelly or cream containers, cups, robs and trays. These small items can have relatively complex shapes with reasonably even thickness. Large products are generally made from cut sheets at a lower though-put rate, and they are usually of simple shapes. Fisher & Paykel's vacuum form moulding machines produce the majority of pre-forms for refrigerators and freezers. Many other interior parts are also made by the same or similar processes.FIGURE 5.Three basic methods of thermoforming.7 Injection mouldingInjection moulding has always been one of the most common processing methods for plastics. Nowadays countless parts in many electrical appliances, automobiles and office equipment are injection moulded. The most common injection moulding machinery is the reciprocating screw machine, whose process can be divided into several stages as seen in Figure 6. At the plastication stage, the feed unit operates as an extntder, melting and homogenising the material in the screw/barrel system. The screw, however, is allowed to retract in order to make room for themolten material in a space at the cylinder head, called material reservoir, between the screw tip and a closed valve or an obstntction of solidified material from the previous shot. At the injection stage, the screw is used as a ram (piston) for rapid transfer of the molten material from the reservoir to the cavity between the two halves of the closed mould. Since the mould is kept at a temperature below the solidification temperature of the material, it is essential to inject the molten material rapidly enough to ensure complete filling of the cavity. A high holding or packing pressure is normally exerted, to partially compensate for the thermal contraction of the material upon cooling. The cooling of the material in the mould often limits the production time because of the low thermal conductivity of polymers. The mould, after being cooled, can be opened and the solid product ejected.Although the screw machine is by far the most popular, plunger injection machines are also used to give products some unique features. There is no shearing or mixing action, as a plunger does not rotate. The resulting moulded part can take on a marbled appearance with swirls of two or more colours. This may be the desired finish for certain products. Regardless of different machines, injection moulding yields a high productivity and allows the products to have many fine details such as bosses, location pins, mounting holes, bushings, ribs, flanges, etc. All these features can eliminate many subs equent assembly and finishing operations.A large variety of products can be injection moulded. These include (a) micro-products, moulded in multiple cavity moulds on small precision machines, such as components for watches and microelectronics; (b) medium size products, moulded continuously in very large numbers in dedicated machines or in relatively small runs; and (c) large products, moulded by large machines, such as car dashboard frames, TV cabinets, garden furniture, and small boat hulls. Many of these large plastic parts have a solid skin and a cellular inner structure, hence the process is also known as structural foam moulding.FIGURE 6.Sequence of operations in injection moulding.8 Reaction injection mouldingReaction injection moulding is a relatively new process, which involves the rapid mixing, in precise proportions, of two or more highly reactive liquid components and the immediate injection of the mixture in a closed mould Polymerisation takes place in the mould in a very short period oftime, yielding a solid product. The process is particularly suited to the production of large and relatively thin parts, with less capital investment and operating costs than in thermoplastic injection moulding. The process is also energy efficient, but requires good control of complex reactions.9 ConclusionsBy and large, each moulding process mentioned above has its pros and cons in terms of the materials, products and cost. The plastics industry plays an important role in today's manufacturing industry. Plastics moulding is the most popular process. Whereas injection moulding continues to dominate the sector, other moulding processes make some important contributions toward manufacture of many specific products. Faced by numerous challenges, new processes are making their way into the market. Conscious of energy consumption, moulding machine manufacturers are contemplating innovative designs to economise on the process. There is also a demand for these manufacturers to develop either smaller or larger moulding machines to meet customer demands. The fact that more and more newly developed materials use moulding processes for a manufacturing method provides an extra dimension for the development of the moulding industry.外文翻译译文塑料成型过程有很多关于塑料成型的方法。
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附录2Integrated simulation of the injection molding process withstereolithography moldsAbstract Functional parts are needed for design verification testing, field trials, customer evaluation, and production planning. By eliminating multiple steps, the creation of the injection mold directly by a rapid prototyping (RP) process holds the best promise of reducing the time and cost needed to mold low-volume quantities of parts. The potential of this integration of injection molding with RP has been demonstrated many times. What is missing is the fundamental understanding of how the modifications to the mold material and RP manufacturing process impact both the mold design and the injection molding process. In addition, numerical simulation techniques have now become helpful tools of mold designers and process engineers for traditional injection molding. But all current simulation packages for conventional injection molding are no longer applicable to this new type of injection molds, mainly because the property of the mold material changes greatly. In this paper, an integrated approach to accomplish a numerical simulation of injection molding into rapid-prototyped molds is established and a corresponding simulation system is developed. Comparisons with experimental results are employed for verification, which show that the present scheme is well suited to handle RP fabricated stereolithography (SL) molds.Keywords Injection molding Numerical simulation Rapid prototyping1 IntroductionIn injection molding, the polymer melt at high temperature is injected into the mold under high pressure [1]. Thus, the mold material needs to have thermal and mechanical properties capable of withstanding the temperatures and pressures of the molding cycle. The focus of many studies has been to create theinjection mold directly by a rapid prototyping (RP) process. By eliminating multiple steps, this method of tooling holds the best promise of reducing the time and cost needed to create low-volume quantities of parts in a production material. The potential of integrating injection molding with RP technologies has been demonstrated many times. The properties of RP molds are very different from those of traditional metal molds. The key differences are the properties of thermal conductivity and elastic modulus (rigidity). For example, the polymers used in RP-fabricated stereolithography (SL) molds have a thermal conductivity that is less than onethousandth that of an aluminum tool. In using RP technologies to create molds, the entire mold design and injection-molding process parameters need to be modified and optimized from traditional methodologies due to the completely different tool material. However, there is still not a fundamen tal understanding of how the modifications t o the mold tooling method and material impact both the mold design and the injection molding process parameters. One cannot obtain reasonable results by simply changing a few material properties in current models. Also, using traditional approaches when making actual parts may be generating sub-optimal results. So there is a dire need to study the interaction between the rapid tooling (RT) process and material and injection molding, so as to establish the mold design criteria and techniques for an RT-oriented injection molding process.In addition, computer simulation is an effective approach for predicting the quality of molded parts. Commercially available simulation packages of the traditional injection molding process have now become routine tools of the mold designer and process engineer [2]. Unfortunately, current simulation programs for conventional injection molding are no longer applicable to RP molds, because of the dramatically dissimilar tool material. For instance, in using the existing simulation software with aluminum and SL molds and comparing with experimental results, though the simulation values of part distortion are reasonable for the aluminum mold, results are unacceptable, with the error exceeding 50%. The distortion during injection molding is due to shrinkage and warpage of the plastic part, as well as the mold. For ordinarily molds, the main factor is the shrinkage and warpage of the plastic part, which is modeled accurately in current simulations. But for RP molds, the distortion of the mold has potentially more influence, which have been neglected in current models. For instance, [3] used a simple three-step simulation process to consider the mold distortion, which had too much deviation.In this paper, based on the above analysis, a new simulation system for RP molds is developed. The proposed system focuses on predicting part distortion, which is dominating defect in RP-molded parts. The developed simulation can be applied as an evaluation tool for RP mold design and process optimization. Our simula tion system is verified by an experimental example.Although many materials are available for use in RP technologies, we concentrate on using stereolithography (SL), the original RP technology, to create polymer molds. The SL process uses photopolymer and laser energy to build a part layer by layer. Using SL takes advantage of both the commercial dominance of SL in the RP industry and the subsequent expertise base that has been developed for creating accurate, high-quality parts. Until recently, SL was primarily used to create physical models for visual inspection and form-fit studies with very limited func-tional applications. However, the newer generation stereolithographic photopolymers have improved dimensional, mechanical and thermal properties making it possible to use them for actual functional molds.2 Integrated simulation of the molding process2.1 MethodologyIn order to simulate the use of an SL mold in the injection molding process, an iterative method is proposed. Different software modules have been developed and used to accomplish this task. The main assumption is that temperature and load boundary conditions cause significant distortions in the SL mold. The simulation steps are as follows:1The part geometry is modeled as a solid model, which is translated to a file readable by the flow analysis package.2Simulate the mold-filling process of the melt into a pho topolymer mold, which will output the resulting temperature and pressure profiles.3Structural analysis is then performed on the photopolymer mold model using the thermal and load boundary conditions obtained from the previous step, which calculates the distortion that the mold undergo during the injection process.4If the distortion of the mold converges, move to the next step. Otherwise, the distorted mold cavity is then modeled (changes in the dimensions of the cavity after distortion), and returns to the second step to simulate the melt injection into the distorted mold.5The shrinkage and warpage simulation of the injection molded part is then applied, which calculates the final distor tions of the molded part.In above simulation flow, there are three basic simulation mod ules.2. 2 Filling simulation of the melt2.2.1 Mathematical modelingIn order to simulate the use of an SL mold in the injection molding process, an iterative method is proposed. Different software modules have been developed and used to accomplish this task. The main assumption is that temperature and load boundary conditions cause significant distortions in the SL mold. The simulation steps are as follows:1. The part geometry is modeled as a solid model, which is translated to a file readable by the flow analysis package.2. Simulate the mold-filling process of the melt into a photopolymer mold, which will output the resulting temperature and pressure profiles.3. Structural analysis is then performed on the photopolymer mold model using the thermal and load boundary conditions obtained from the previous step, which calculates the distortion that the mold undergo during the injection process.4. If the distortion of the mold converges, move to the next step. Otherwise, the distorted mold cavity is then modeled (changes in the dimensions of the cavity after distortion), and returns to the second step to simulate the melt injection into the distorted mold.5. The shrinkage and warpage simulation of the injection molded part is then applied, which calculates the final distortions of the molded part.In above simulation flow, there are three basic simulation modules.2.2 Filling simulation of the melt2.2.1 Mathematical modelingComputer simulation techniques have had success in predicting filling behavior in extremely complicated geometries. However, most of the current numerical implementation is based on a hybrid finite-element/finite-difference solution with the middleplane model. The application process of simulation packages based on this model is illustrated in Fig. 2-1. However, unlike the surface/solid model in mold-design CAD systems, the so-called middle-plane (as shown in Fig. 2-1b) is an imaginary arbitrary planar geometry at the middle of the cavity in the gap-wise direction, which should bring about great inconvenience in applications. For example, surface models are commonly used in current RP systems (generally STL file format), so secondary modeling is unavoidable when using simulation packages because the models in the RP and simulation systems are different. Considering these defects, the surface model of the cavity is introduced as datum planes in the simulation, instead of the middle-plane.According to the previous investigations [4–6], fillinggoverning equations for the flow and temperature field can be written as:where x, y are the planar coordinates in the middle-plane, and z is the gap-wise coordinate; u, v,w are the velocity components in the x, y, z directions; u, v are the average whole-gap thicknesses; and η, ρ,CP (T), K(T) represent viscosity, density, specific heat and thermal conductivity of polymer melt, respectively.Fig.2-1 a–d. Schematic procedure of the simulation with middle-plane model. a The 3-D surface model b The middle-plane model c The meshed middle-plane model d The display of the simulation result In addition, boundary conditions in the gap-wise direction can be defined as:where TW is the constant wall temperature (shown in Fig. 2a).Combining Eqs. 1–4 with Eqs. 5–6, it follows that the distributions of the u, v, T, P at z coordinates should be symmetrical, with the mirror axis being z = 0, and consequently the u, v averaged in half-gap thickness is equal to that averaged in wholegap thickness. Based on this characteristic, we can divide the whole cavity into two equal parts in the gap-wise direction, as described by Part I and Part II in Fig. 2b. At the same time, triangular finite elements are generated in the surface(s) of the cavity (at z = 0 in Fig. 2b), instead of the middle-plane (at z = 0 in Fig. 2a). Accordingly, finite-difference increments in the gapwise direction are employed only in the inside of the surface(s) (wall to middle/center-line), which, in Fig. 2b, means from z = 0 to z = b. This is single-sided instead of two-sided with respect to the middle-plane (i.e. from the middle-line to two walls). In addition, the coordinate system is changed from Fig. 2a to Fig. 2b to alter the finite-element/finite-difference scheme, as shown in Fig. 2b. With the above adjustment, governing equations are still Eqs. 1–4. However, the original boundary conditions inthe gapwise direction are rewritten as:Meanwhile, additional boundary conditions must be employed at z = b in order to keep the flows at the juncture of the two parts at the same section coordinate [7]:where subscripts I, II represent the parameters of Part I and Part II, respectively, and Cm-I and Cm-II indicate the moving free melt-fronts of the surfaces of the divided two parts in the filling stage.It should be noted that, unlike conditions Eqs. 7 and 8, ensuring conditions Eqs. 9 and 10 are upheld in numerical implementations becomes more difficult due to the following reasons:1. The surfaces at the same section have been meshed respectively, which leads to a distinctive pattern of finite elements at the same section. Thus, an interpolation operation should be employed for u, v, T, P during the comparison between the two parts at the juncture.2. Because the two parts have respective flow fields with respect to the nodes at point A and point C (as shown in Fig. 2b) at the same section, it is possible to have either both filled or one filled (and one empty). These two cases should be handled separately, averaging the operation for the former, whereas assigning operation for the latter.3. It follows that a small difference between the melt-fronts is permissible. That allowance can be implemented by time allowance control or preferable location allowance control of the melt-front nodes.4. The boundaries of the flow field expand by each melt-front advancement, so it is necessary to check the condition Eq. 10 after each change in the melt-front.5. In view of above-mentioned analysis, the physical parameters at the nodes of the same section should be compared and adjusted, so the information describing finite elements of the same section should be prepared before simulation, that is, the matching operation among the elements should be preformed.Fig. 2a,b. Illustrative of boundary conditions in the gap-wise direction a of the middle-plane model b of thesurface model2.2.2 Numerical implementationPressure field. In modeling viscosity η, which is a function of shear rate, temperature and pressure of melt, the shear-thinning behavior can be well represented by a cross-type model such as:where n corresponds to the power-law index, and τ∗ characterizes the shear stress level of the transition region between the Newtonian and power-law asymptotic limits. In terms of an Arrhenius-type temperature sensitivity and exponential pressure dependence, η0(T, P) can be represented with reasonable accuracy as follows:Equations 11 and 12 constitute a five-constant (n, τ∗, B, Tb, β) representation for viscosity. The shear rate for viscosity calculation is obtained by:Based on the above, we can infer the following filling pressure equation from the governing Eqs. 1–4:where S is calculated by S = b0/(b−z)2η d z. Applying the Galerkin method, the pressure finite-element equation is deduced as:where l_ traverses all elements, including node N, and where I and j represent the local node number in element l_ corresponding to the node number N and N_ in the whole, respectively. The D(l_) ij is calculated as follows:where A(l_) represents triangular finite elements, and L(l_) i is the pressure trial function in finite elements.Temperature field. To determine the temperature profile across the gap, each triangular finite element at the surface is further divided into NZ layers for the finite-difference grid.The left item of the energy equation (Eq. 4) can be expressed as:where TN, j,t represents the temperature of the j layer of node N at time t.The heat conduction item is calculated by:where l traverses all elements, including node N, and i and j represent the local node number in element l corresponding to the node number N and N_ in the whole, respectively.The heat convection item is calculated by:For viscous heat, it follows that:Substituting Eqs. 17–20 into the energy equation (Eq. 4), the temperature equation becomes:2.3 Structural analysis of the moldThe purpose of structural analysis is to predict the deformation occurring in the photopolymer mold due to the thermal and mechanical loads of the filling process. This model is based on a three-dimensional thermoelastic boundary element method (BEM). The BEM is ideally suited for this application because only the deformation of the mold surfaces is of interest. Moreover, the BEM has an advantage over other techniques in that computing effort is not wasted on calculating deformation within the mold.The stresses resulting from the process loads are well within the elastic range of the mold material. Therefore, the mold deformation model is based on a thermoelastic formulation. The thermal and mechanical properties of the mold are assumed to be isotropic and temperature independent.Although the process is cyclic, time-averaged values of temperature and heat flux are used for calculating the mold deformation. Typically, transient temperature variations within a mold have been restricted to regions local to the cavity surface and the nozzle tip [8]. The transients decay sharply with distance from the cavity surface and generally little variation is observed beyond distances as small as 2.5 mm. This suggests that the contribution from the transients to the deformation at the mold block interface is small, and therefore it is reasonable to neglect the transient effects. The steady state temperature field satisfies Laplace’s equation 2T = 0 and the time-averaged boundary conditions. The boundary conditions on the mold surfaces are described in detail by Tang et al. [9]. As for the mechanical boundary conditions, the cavity surface is subjected to the melt pressure, the surfaces of the mold connected to the worktable are fixed in space, and other external surfaces are assumed to be stress free.The derivation of the thermoelastic boundary integral formulation is well known [10]. It is given by:where uk, pk and T are the displacement, traction and temperature,α, ν represent the thermal expansion coefficient and Poisson’s ratio of the material, and r = |y−x|. clk(x) is the surfacecoefficient which depends on the local geometry at x, the orientation of the coordinate frame and Poisson’s ratio for the domain [11]. The fundamental displacement ˜ulk at a point y in the xk direction, in a three-dimensional infinite isotropic elastic domain, results from a unit load concentrated at a point x acting in the xl direction and is of the form:where δlk is the Kronecker delta function and μ is the shear modulus of the mold material.The fundamental traction ˜plk , measured at the point y on a surface with unit normal n, is:Discretizing the surface of the mold into a total of N elements transforms Eq. 22 to:where Γn refers to the n th surface element on the domain.Substituting the appropriate linear shape functions into Eq. 25, the linear boundary element formulation for the mold deformation model is obtained. The equation is applied at each node on the discretized mold surface, thus giving a system of 3N linear equations, where N is the total number of nodes. Each node has eight associated quantities: three components of displacement, three components of traction, a temperature and a heat flux. The steady state thermal model supplies temperature and flux values as known quantities for each node, and of the remaining six quantities, three must be specified. Moreover, the displacement values specified at a certain number of nodes must eliminate the possibility of a rigid-body motion or rigid-body rotation to ensure a non-singular system of equations. The resulting system of equations is assembled into a integrated matrix, which is solved with an iterative solver.2.4 Shrinkage and warpage simulation of the molded partInternal stresses in injection-molded components are the principal cause of shrinkage and warpage. These residual stresses are mainly frozen-in thermal stresses due to inhomogeneous cooling, when surface layers stiffen sooner than the core region, as in free quenching. Based onthe assumption of the linear thermo-elastic and linear thermo-viscoelastic compressible behavior of the polymeric materials, shrinkage and warpage are obtained implicitly using displacement formulations, and the governing equations can be solved numerically using a finite element method.With the basic assumptions of injection molding [12], the components of stress and strain are given by:The deviatoric components of stress and strain, respectively, are given byUsing a similar approach developed by Lee and Rogers [13] for predicting the residual stresses in the tempering of glass, an integral form of the viscoelastic constitutive relationships is used, and the in-plane stresses can be related to the strains by the following equation:Where G1 is the relaxation shear modulus of the material. The dilatational stresses can be related to the strain as follows:Where K is the relaxation bulk modulus of the material, and the definition of α and Θ is: If α(t) = α0, applying Eq. 27 to Eq. 29 results in:Similarly, applying Eq. 31 to Eq. 28 and eliminating strain εxx(z, t) results in:Employing a Laplace transform to Eq. 32, the auxiliary modulus R(ξ) is given by:Using the above constitutive equation (Eq. 33) and simplified forms of the stresses and strains in the mold, the formulation of the residual stress of the injection molded part during the cooling stage is obtain by:Equation 34 can be solved through the application of trapezoidal quadrature. Due to the rapid initial change in the material time, a quasi-numerical procedure is employed for evaluating the integral item. The auxiliary modulus is evaluated numerically by the trapezoidal rule.For warpage analysis, nodal displacements and curvatures for shell elements are expressed as:where [k] is the element stiffness matrix, [Be] is the derivative operator matrix, {d} is the displacements, and {re} is the element load vector which can be evaluated by:The use of a full three-dimensional FEM analysis can achieve accurate warpage results, however, it is cumbersome when the shape of the part is very complicated. In this paper, a twodimensional FEM method, based on shell theory, was used because most injection-molded parts have a sheet-like geometry in which the thickness is much smaller than the other dimensions of the part. Therefore, the part can be regarded as an assembly of flat elements to predict warpage. Each three-node shell element is a combination of a constant strain triangular element (CST) and a discrete Kirchhoff triangular element (DKT), as shown in Fig. 3. Thus, the warpage can be separated into plane-stretching deformation of the CST and plate-bending deformation of the DKT, and correspondingly, the element stiffness matrix to describe warpage can also be divided into the stretching-stiffness matrix and bending-stiffness matrix.Fig. 3a–c. Deformation decomposition of shell element in the local coordinate system. a In-plane stretchingelement b Plate-bending element c Shell element3 Experimental validationTo assess the usefulness of the proposed model and developed program, verification is important. The distortions obtained from the simulation model are compared to the ones from SL injection molding experiments whose data is presented in the literature [8]. A common injection molded part with the dimensions of 36×36×6 mm is considered in the experiment, as shown in Fig. 4. The thickness dimensions of the thin walls and rib are both 1.5 mm; and polypropylene was used as the injection material. The injection machine was a production level ARGURY Hydronica 320-210-750 with the following process parameters: a melt temperature of 250 ◦C; an ambient temperature of 30 ◦C; an injection pressure of 13.79 MPa; an injection time of 3 s; and a cooling time of 48 s. The SL material used, Dupont SOMOSTM 6110 resin, has the ability to resist temperatures of up to 300 ◦C temperatures. As mentioned above, thermal conductivity of the mold is a major factor that differentiates between an SL and a traditional mold. Poor heat transfer in the mold would produce a non-uniform temperature distribution, thus causing warpage that distorts the completed parts. For an SL mold, a longer cycle time would be expected. The method of using a thin shell SL mold backed with a higher thermal conductivity metal (aluminum) was selected to increase thermal conductivity of the SL mold.Fig. 4. Experimental cavity modelFig. 5. A comparison of the distortion variation in the X direction for different thermal conductivity; where “Experimental”, “present”, “three-step”, and “conventional” mean the results of the experimental, the presented simulation, the three-step simulation process and the conventional injection molding simulation, respectively.Fig. 6. Comparison of the distortion variation in the Y direction for different thermal conductivitiesFig. 7. Comparison of the distortion variation in the Z direction for different thermal conductivitiesFig. 8. Comparison of the twist variation for different thermal conductivities For this part, distortion includes the displacements in three directions and the twist (the difference in angle between two initially parallel edges). The validation results are shown in Fig.5 to Fig. 8. These figures also include the distortion values predicted by conventional injection molding simulation and the three-step model reported in [3].4 ConclusionsIn this paper, an integrated model to accomplish the numerical simulation of injection molding into rapid-prototyped molds is established and a corresponding simulation system is developed. For verification, an experiment is also carried out with an RPfabricated SL mold.It is seen that a conventional simulation using current injection molding software breaks down for a photopolymer mold. It is assumed that this is due to the distortion in the mold caused by the temperature and load conditions of injection. The three-step approach also has much deviation. The developed model gives results closer to experimental.Improvement in thermal conductivity of the photopolymer significantly increases part quality. Since the effect of temperature seems to be more dominant than that of pressure (load), an improvement in the thermal conductivity of the photopolymer can improve the part quality significantly.Rapid Prototyping (RP) is a technology makes it possible to manufacture prototypes quickly and inexpensively, regardless of their complexity. Rapid Tooling (RT) is the next step in RP’s steady progress and much work is being done to obtain more accurate tools to define the parameters of the process. Existing simulation tools can not provide the researcher with a useful means of studying relative changes. An integrated model, such as the one presented in this paper, is necessary to obtain accurate predictions of the actual quality of final parts. In the future, we expect to see this work expanded to develop simulations program for injection into RP molds manufactured by other RT processes.References1. Wang KK (1980) System approach to injection molding process. Polym-Plast Technol Eng 14(1):75–93.2. Shelesh-Nezhad K, Siores E (1997) Intelligent system for plastic injection molding process design. J Mater Process Technol 63(1–3):458–462.3. Aluru R, Keefe M, Advani S (2001) Simulation of injection molding into rapid-prototyped molds. Rapid Prototyping J 7(1):42–51.4. Shen SF (1984) Simulation of polymeric flows in the injection molding process. Int J Numer Methods Fluids 4(2):171–184.5. Agassant JF, Alles H, Philipon S, Vincent M (1988) Experimental and theoretical study of the injection molding of thermoplastic materials. Polym Eng Sci 28(7):460–468.6. Chiang HH, Hieber CA, Wang KK (1991) A unified simulation of the filling and post-filling stages in injection molding. Part I: formulation. Polym Eng Sci 31(2):116–124.7. Zhou H, Li D (2001) A numerical simulation of the filling stage in injection molding based on a surface model. Adv Polym Technol 20(2):125–131.8. Himasekhar K, Lottey J, Wang KK (1992) CAE of mold cooling in injection molding using a three-dimensional numerical simulation. J EngInd Trans ASME 114(2):213–221.9. Tang LQ, Pochiraju K, Chassapis C, Manoochehri S (1998) Computeraided optimization approach for the design of injection mold cooling systems. J Mech Des, Trans ASME 120(2):165–174.10. Rizzo FJ, Shippy DJ (1977) An advanced boundary integral equation method for three-dimensional thermoelasticity. Int J Numer Methods Eng 11:1753–1768.11. Hartmann F (1980) Computing the C-matrix in non-smooth boundary points. In: New developments in boundary element methods, CML Publications, Southampton, pp 367–379.12. Chen X, Lama YC, Li DQ (2000) Analysis of thermal residual stress in plastic injection molding. J Mater Process Technol 101(1):275–280.13. Lee EH, Rogers TG (1960) Solution of viscoelastic stress analysis problems using measured creep or relaxation function. J Appl Mech 30(1):127–134.14. 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注塑模具专业英语 塑胶模具英语 注塑成型专业英语 Injection Mould English
abrasive grinding 强力磨削abrasive 磨料的,研磨的absence 不在,缺席accesssory 附件accommodate 适应accordingly 因此,从而,相应地accuracy 精度,准确性actuate 开动(机器),驱动adequate 足够的adhesive 粘合剂adjacent 邻近的adopt 采用advance 进步advisable 可取的agitate 摇动a large extent 很大程度algorithm 算法align 定位,调准alignment 校直all-too-frequent 频繁allowance 容差,余量alternate 交替,轮流alternatively 做为选择,也许aluminiun 铝ample 充足的analysis 分析ancillary 补助的,副的angular 有角的annealing 退火aperture 孔applied loads 作用力appropriate 适当的arc 弧,弓形arise 出现,发生arrange 安排article 制品,产品ascertain 确定,查明assemble 组装attitude 态度auxiliary 辅助的avoid 避免axis 轴axle 轮轴,车轴alternative 替换物backup 备份batch 一批bearing 轴承,支座bed 床身behavior 性能bench-work 钳工工作bend 弯曲beneath 在•••下bin 仓,料架blank 坯料blank 冲裁,落料blanking 落料模blast 一阵(风)blemish 缺点,污点bolster 模座,垫板boring 镗削,镗孔bracket 支架brass 黄铜break down 破坏breakage 破坏brine 盐水brittle 易碎的buffer 缓冲器built-in 内装的bulging 凸肚burr 毛刺bush 衬套by far •••得多,最by means of 借助于boost 推进cabinet 橱柜call upon 要求carbide 碳化物carburzing 渗碳carriage 拖板,大拖板carry along 一起带走carry down over 从•••上取下carry out 完成case hardening 表面硬化case 壳,套cast steel 铸钢casting 铸造,铸件category 种类caution 警告,警示cavity and core plates 凹模和凸模板cavity 型腔,腔,洞centre-drilling 中心孔ceramic 陶瓷制品chain doted line 点划线channel 通道,信道characteristic 特性check 核算chip 切屑,铁屑chuck 卡盘chute 斜道circa 大约circlip (开口)簧环circuit 回路,环路circulate (使)循环clamp 夹紧clamp 压板clay 泥土clearance 间隙clip 切断,夹住cold hobbing 冷挤压cold slug well 冷料井collapse 崩塌,瓦解collapsible 可分解的combination 组合commence 开始,着手commence 开始commercial 商业的competitive 竞争的complementary 互补的complexity 复杂性complication 复杂化compression 压缩comprise 包含compromise 妥协,折衷concern with 关于concise 简明的,简练的confront 使面临connector 连接口,接头consequent 随之发生的,必然的console 控制台consume 消耗,占用consummate 使完善container 容器contingent 可能发生的CPU (central processing unit) 中央处理器conventional 常规的converge 集中于一点conversant 熟悉的conversion 换算,转换conveyer 运送装置coolant 冷却液coordinate (使)协调copy machine 仿形(加工)机床core 型芯,核心corresponding 相应的counteract 反作用,抵抗couple with 伴随contour 轮廓crack (使)破裂,裂纹critical 临界的cross-hatching 剖面线cross-section drawn 剖面图cross-slide 横向滑板CRT (cathoder-ray tube) 阴极射线管crush 压碎cryogenic 低温学的crystal 结晶状的cubic 立方的,立方体的cup (使)成杯状,引伸curable 可矫正的curvature 弧线curve 使弯曲cutter bit 刀头,刀片cyanide 氰化物complicated 复杂的dash 破折号daylight 板距decline 下落,下降,减少deform (使)变形demonstrate 证明depict 描述deposite 放置depression 凹穴descend 下降desirable 合适的detail 细节,详情deterioration 退化,恶化determine 决定diagrammmatic 图解的,图表的dictate 支配die 模具,冲模,凹模dielectric 电介质die-set 模架digital 数字式数字dimensional 尺寸的,空间的discharge 放电,卸下,排出discharge 卸下discrete 离散的,分立的dislodge 拉出,取出dissolution 结束distinct 不同的,显著的distort 扭曲distort (使)变形,扭曲distributed system 分布式系统dowel 销子dramaticlly 显著地drastic 激烈的draughting 绘图draughtsman 起草人drawing 制图drill press 钻床drum 鼓轮dual 双的,双重的ductility 延展性dynamic 动力的edge 边缘e.g.(exempli gratia) [拉]例如ejector 排出器ejector plate 顶出板ejector rob 顶杆elasticity 弹性electric dicharge machining 电火花加工electrode 电极electro-deposition 电铸elementary 基本的eliminate 消除,除去elongate (使)伸长,延长emerge 形成,显现emphasise 强调endeavour 尽力engagement 约束,接合enhance 提高,增强ensure 确保,保证erase 抹去,擦掉evaluation 评价,估价eventually 终于evolution 进展excecution 执行,完成execute 执行electrochemical machining 电化学加工exerte 施加experience 经验explosive 爆炸(性)的extend 伸展external 外部的extract 拔出extreme 极端extremely 非常地extremity 极端extrusion 挤压,挤出envisage 设想Fahrenheit 华氏温度fabricate 制作,制造flat-panel technology 平面(显示)技术facility 设备facing 端面车削fall within 属于,适合于fan 风扇far from 毫不,一点不,远非fatigue 疲劳feasible 可行的feature 特色,特征feed 进给feedback 反馈female 阴的,凹形的ferrule 套管file system 文件系统fitter 装配工,钳工fix 使固定,安装fixed half and moving half 定模和动模facilitate 帮助flexibility 适应性,柔性flexible 柔韧的flow mark 流动斑点follow-on tool 连续模foregoing 在前的,前面的foretell 预测,预示,预言forge 锻造forming 成型four screen quadrants 四屏幕象限fracture 破裂free from 免于gap 裂口,间隙gearbox 齿轮箱govern 统治,支配,管理grain 纹理graphic 图解的grasp 抓住grid 格子,网格grind 磨,磨削,研磨grinding 磨光,磨削grinding machine 磨床gripper 抓爪,夹具groove 凹槽guide bush 导套guide pillar 导柱guide pillars and bushes 导柱和导套handset 电话听筒hardness 硬度hardware 硬件headstock 床头箱,主轴箱hexagonal 六角形的,六角的hindrance 障碍,障碍物hob 滚刀,冲头hollow-ware 空心件horizontal 水平的hose 软管,水管hyperbolic 双曲线的i.e. (id est) [拉]也就是identical 同样的identify 确定,识别idle 空闲的immediately 正好,恰好impact 冲击impart 给予implement 实现impossibility 不可能impression 型腔in contact with 接触in terms of 依据inasmuch (as) co因为,由于inch-to-metric conversions 英公制转换inclinable 可倾斜的inclusion 内含物inconspicuous 不显眼的incorporate 合并,混合indentation 压痕indenter 压头independently 独自地,独立地inevitably 不可避免地inexpensive 便宜的inherently 固有的injection mould 注塑模injection 注射in-line-of-draw 直接脱模insert 嵌件inserted die 嵌入式凹模inspection 检查,监督installation 安装integration 集成intelligent 智能的intentinonally 加强地,集中地interface 界面internal 内部的interpolation 插值法investment casting 熔模铸造irregular 不规则的,无规律irrespective of 不论,不管irrespective 不顾的,不考虑的issue 发布,发出joint line 结合线kerosene 煤油keyboard 健盘knock 敲,敲打lance 切缝lathe 车床latitude 自由lay out 布置limitation 限度,限制,局限(性) local intelligence 局部智能locate 定位logic 逻辑longitudinal 纵向的longitudinally 纵向的look upon 视作,看待lubrication 润滑machine shop 车间machine table 工作台machining 加工made-to-measure 定做maintenance 维护,维修majority 多数make use of 利用male 阳的,凸形的malfunction 故障mandrel 心轴manifestation 表现,显示massiveness 厚实,大块measure 大小,度量microcomputer 微型计算机microns 微米microprocessor 微处理器mild steel 低碳钢milling machine 铣床mineral 矿物,矿产minimise 把减到最少,最小化minute 微小的mirror image 镜像mirror 镜子moderate 适度的modification 修改,修正modulus 系数mold 模,铸模mold 制模,造型monitor 监控monograph 专著more often than not 常常motivation 动机mould split line 模具分型线moulding 注塑件move away from 抛弃multi-imprssion mould 多型腔模narrow 狭窄的NC (numerical control) 数控nevertheless 然而,不过nonferrous 不含铁的,非铁的normally 通常地novice 新手,初学者nozzle 喷嘴,注口numerical 数字的objectionable 有异议的,讨厌的observe 观察obviously 明显地off-line 脱机的on-line 联机operational 操作的,运作的opportunity 时机,机会opposing 对立的,对面的opposite 反面optimization 最优化orient 确定方向orthodox 正统的,正规的overall 全面的,全部的overbend 过度弯曲overcome 克服,战胜overlaping 重叠overriding 主要的,占优势的opposite 对立的,对面的pack 包装package 包装pallet 货盘panel 面板paraffin 石蜡parallel 平行的penetration 穿透peripheral 外围的periphery 外围permit 许可,允许pessure casting 压力铸造pillar 柱子,导柱pin 销,栓,钉pin-point gate 针点式浇口piston 活塞plan view 主视图plasma 等离子plastic 塑料platen 压板plotter 绘图机plunge 翻孔plunge 投入plunger 柱塞pocket-size 袖珍portray 描绘pot 壶pour 灌,注practicable 行得通的preferable 更好的,更可取的preliminary 初步的,预备的press setter 装模工press 压,压床,冲床,压力机prevent 妨碍primarily 主要地procedure 步骤,方法,程序productivity 生产力profile 轮廓progressively 渐进地project 项目project 凸出projection 突出部分proper 本身的property 特性prototype 原形proximity 接近prudent 谨慎的punch 冲孔punch shapper tool 刨模机punch-cum-blanking die 凹凸模punched tape 穿孔带purchase 买,购买push back pin 回程杆pyrometer 高温计quality 质量quandrant 象限quantity 量,数量quench 淬火radial 放射状的ram 撞锤rapid 迅速的rapidly 迅速地raster 光栅raw 未加工的raw material 原材料ream 铰大reaming 扩孔,铰孔recall 记起,想起recede 收回,后退recess 凹槽,凹座,凹进处redundancy 过多re-entrant 凹入的refer 指,涉及,谈及reference 参照,参考refresh display 刷新显示register ring 定位环register 记录,显示,记数regrind 再磨研relative 相当的,比较的relay 继电器release 释放relegate 把降低到reliability 可靠性relief valves 安全阀relief 解除relieve 减轻,解除remainder 剩余物,其余部分removal 取出remove 切除,切削reposition 重新安排represent 代表,象征reputable 有名的,受尊敬的reservoir 容器,储存器resident 驻存的resist 抵抗resistance 阻力,抵抗resolution 分辨率respective 分别的,各自的respond 响应,作出反应responsibility 责任restrain 抑制restrict 限制,限定restriction 限制retain 保持,保留retaining plate 顶出固定板reveal 显示,展现reversal 反向right-angled 成直角的rigidity 钢度rod 杆,棒rotate (使)旋转rough machining 粗加工rough 粗略的routine 程序rubber 橡胶runner and gate systems 流道和浇口系统sand casting 砂型铸造satisfactorily 满意地saw 锯子scale 硬壳score 刻划scrap 废料,边角料,切屑screwcutting 切螺纹seal 密封section cutting plane 剖切面secure 固定secure 紧固,夹紧,固定segment 分割sensitive 敏感的sequence 次序sequential 相继的seriously 严重地servomechanism 伺服机构servomotor 伺服马达setter 安装者set-up 机构sever 切断severity 严重shaded 阴影的shank 柄shear 剪,切shot 注射shrink 收缩side sectional view 侧视图signal 信号similarity 类似simplicity 简单single-point cutting tool 单刃刀具situate 使位于,使处于slide 滑动,滑落slideway 导轨slot 槽slug 嵌条soak 浸,泡,均热software 软件solid 立体,固体solidify (使)凝固solidify (使)固化solution 溶液sophisiticated 尖端的,完善的sound 结实的,坚固的spark erosion 火花蚀刻spindle 主轴spline 花键split 侧向分型,分型spool 线轴springback 反弹spring-loaded 装弹簧的sprue bush 主流道衬套sprue puller 浇道拉杆square 使成方形Servomechanism Laboratoies 伺服机构实验室stage 阶段standardisation 标准化startling 令人吃惊的steadily 稳定地step-by-step 逐步stickiness 粘性stiffness 刚度stock 毛坯,坯料storage tube display 储存管显示storage 储存器straightforward 直接的strain 应变strength 强度stress 压力,应力stress-strain 应力--应变stretch 伸展strike 冲击stringent 严厉的stripper 推板stroke 冲程,行程structrural build-up 结构上形成的sub-base 垫板subject 使受到submerge 淹没subsequent 后来的subsequently 后来,随后substantial 实质的substitute 代替,替换subtract 减,减去suitable 合适的,适当的suitably 合适地sunk 下沉,下陷superior 上好的susceptible 易受影响的sweep away 扫过symmetrical 对称的synchronize 同步,同时发生tactile 触觉的,有触觉的tailstock 尾架tapered 锥形的tapping 攻丝technique 技术tempering 回火tendency 趋向,倾向tensile 拉力的,可拉伸的tension 拉紧,张紧terminal 终端机terminology 术语,用辞theoretically 理论地thereby 因此,从而thermoplastic 热塑性的thermoplastic 热塑性塑料thermoset 热固性thoroughly 十分地,彻底地thread pitch 螺距thread 螺纹thrown up 推上tilt 倾斜,翘起tolerance 公差two-plate mould 双板式注射模tong 火钳tonnage 吨位,总吨数tool point 刀锋tool room 工具车间toolholder 刀夹,工具柄toolmaker 模具制造者toolpost grinder 工具磨床toolpost 刀架torsional 扭转的toughness 韧性trace 追踪transverse 横向的tray 盘,盘子,蝶treatment 处理tremendous 惊人的,巨大的trend 趋势trigger stop 始用挡料销tungsten 钨turning 车削twist 扭曲,扭转tracer-controlled milling machine 仿形铣床ultimately 终于undercut moulding 侧向分型模undercut 侧向分型undercut 底切underfeed 底部进料的undergo 经受underside 下面,下侧undue 不适当的,过度的uniform 统一的,一致的utilize 利用Utopian 乌托邦的,理想化的valve 阀vaporize 汽化vaporize (使)蒸发variation 变化various 不同的,各种的vector feedrate computation 向量进刀速率计算vee 字形velocity 速度versatile 多才多艺的,万用的vertical 垂直的via prep经,通过vicinity 附近viewpoint 观点wander 偏离方向warp 翘曲washer 垫圈wear 磨损well line 结合线whereupon 于是winding 绕,卷with respect to 相对于withstand 经受,经得起work 工件workstage 工序wrinkle 皱纹使皱yield 生产zoom 图象电子放大。
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Figure 1. Organization of the IKEM Project
2 Intelligent Mold Design Tool
The mold design tool in its basic form is a Visual Basic application taking input from a text file that contains information about the part and a User Input form. The text file contains information about the part geometry parsed from a Pro/E information file. The input is used to estimate the dimensions of mold and various other features.
2.1 Literature Review
Design of molds is another stage of the injection molding process where the experience of an engineer largely helps automate the process and increase its efficiency. The issue that needs attention is the time that goes into designing the molds. Often, design engineers refer to tables and standard handbooks while designing a mold, which consumes lot of time. Also, a great deal of time goes into modeling components of the mold in standard CAD software. Different
researchers have dealt with the issue of reducing the time it takes to design the mold in different ways. Koelsch and James have employed group technology techniques to reduce the mold design time. A unique coding system that groups a class of injection molded parts, and the tooling required ininjection molding is developed which is general and can be applied to other product lines.
A software system to implement the coding system has also been developed. Attempts were also directed towards the automation of the mold design process by capturing experience and knowledge of engineers in the field. The development of a concurrent mold design system is one such approach that attempts to develop a systematic methodology for injection mold design processes in a concurrent engineering environment. The objective of their research was to develop a mold development process that facilitates concurrent engineering-based practice, and
Figure 2. Organization of the Mold Design Module.
While most of the input, like the number of cavities, cavity image dimensions, cycle time are based on the client specifications, other input like the plasticizing capacity, shots per minute etc., can be obtained from the machine specifications. The output of the application contains mold dimensions and other information, which clearly helps in selecting the standard mold base from catalogs. Apart from the input and output, the Figure 2 also shows the various modules that produce the final output.
2.5 Framing rules
At this stage, the expert’s knowledge is represented in the form of multiple If-Then statements. The rules may be representations of both qualitative and quantitative knowledge. By qualitative knowledge, we mean deterministic information about a problem that can be solved computationally. By qualitative we mean information that is not deterministic, but merely followed as a rule based on previous cases where the rule has worked. A typical rule is illustrated below:
If Material = “Acetal” And
Runner Length <= 3 And
Runner Length > 0 Then
Runner Diameter =0.062
End If
When framing the rules it is important that we represent the information in a compact way while avoiding redundancy, incompleteness and inconsistency. Decision tables help take care of all the above concerns by checking for redundancy and comprehensive expression of the problem statement. As an example, in the process of selecting an appropriate mold base, the size of mold base depends on the number of cavities and inserts. To ensure that all possible combinations of。