塑料件设计指导《Plastic Design Guide》

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塑料零件设计实例

*一般在设计塑料件时,尽可能的均一肉厚.以材料为ABS为例,生产大面板时为了强度及好跑料容易射出成型,其主要面厚度大都设计为2.5mm~3.0mm.小面板如HDD DummyBezel其主要面厚度大都设计为1.8mm~2.5mm.在周围长出一周边墙时肉厚最好小于基础面.3.0mm的基面大约可用2.2~2.5mm的壁厚.若基面与周围壁厚同为3.0mm但内R角为0.5外R角微3.5因为其肉厚都相同则缩水现象也不至于发生.不幸若有外观要求,其R角要求小于2mm,则产生缩水现象非长高.也可沿着壁内做一圈小槽沟来降低肉厚防止缩水.
Mechanical Plastic Design Guide Line
一般在设计塑料件时,尽可能的均一肉厚.即使要改变厚度也要缓和进方式,避免急速,忽然的变化,会在另一边的平面造成应阴影.
Mechanical Plastic Design Guide Line
*一般在设计塑料件时,尽可能的均一肉厚.在平面上多出的厚度会在凸出物的背面造成缩水的凹陷.为避免此情形可将凸出物视设计功能改成肋状(Rib),其Rib 宽度也勿大于肉厚的1/2.
Mechanical Plastic Design Guide Line
*一般在面板上都会有一些指示灯(LED Lens),运用导光柱(Lens)将机壳内Control board上LED的光引导至面板使操作者可清楚使用状况.建议--在设计时將 Lens凸出面板0.2~0.5mm.一則:若设计时是将Lens与面板平齐,由于组装的公差,有可能有些Lens会凹陷不在与面板同一平面上而影响外观.若设计为些许的凸出时,即使有组装的公差也较不会造成内凹现象. 二則:Lens些许的凸出时即使在侧面也较容易看到亮灯的情形.
Mechanical Plastic Design Guide Line

老外精心总结的塑料件设计提要

parison of materialsPlastic is not metalComparison of materials –Many plastic designs still continue to be derived from“metal parts”. In the series commencing here the authors set out to describe the points that require attention when designing in plastics rather than traditional materials.Different basic material characteristicsThe properties of plastics materials can vary over a far wider range than all other engineering materials. Through the addition of fillers/reinforcing materials and modifiers the property profile of virtually any base polymer can be radically altered. Most basic properties of plastics, however, form a marked contrast to those of metals. For example, in a direct comparison, metals have higher– density– maximum service temperature – rigidity/strength– thermal conductivity and – electrical conductivity,while the– mechanical damping – thermal expansion – elongation at break and – toughnessof engineering thermoplastics are greater by orders of magnitude (see Fig. 1). To produce functional parts in plastic and at the same time save costs, radical design modification is generally necessary if the plastic is being used to replace metal. This process affords an opportunity for complete redesign of the component with possible integration of functions and geometric simplification.T OP T EN D ESIGN T IPS – A S ERIES OF 10 A RTICLESBy Jürgen Hasenauer, Dieter Küper, Jost E. Laumeyer and Ian Welshparison of materials2.Material selection3.Wall thickness4.Ribbing5.Gate positioning6.Cost-saving designs7.General assembly technology 8.Welding technology 9.Tolerances 10.Check listFig. 1Snap-fit hooksEncapsulationof metal insertsPipes underinternal pressureBellowsAirbag coverDifferent material behaviourPlastics sometimes exhibit completely different behaviour to that of metals under the same service conditions. For this reason, a functionally efficient, economic design in cast metal can easily fail if repeated in plastic with excessive haste. Plastics designers must therefore be familiar with the properties of this group of materials.Temperature and time dependence of deformation characteristicsThe nearer the service temperature of a material is to its melting point, the more the material’s deformation behaviour will be temperature- and time-dependent. Most plastics exhibit a change in their basic mechanical properties at room temperature or on exposure to short-term stress. Metals, on the other hand, usually display largely unchanged mechanical behaviour right up to the vicinity of their recrystallization temperature (> 300 °C).If the service temperature or deformation rate is varied sufficiently, the deformation behaviour of engineering thermoplastics can change from hard and brittle to rubbery-elastic. An airbag cover, for example, in its particular application involving explosive opening, exhibits completely different deformation behaviour from that of a slowly assembled snap-fit element made of the same material (Fig. 2). Similarly, this snap-fit element has to be assembled in a different way according to whether the temperature conditions are hot or cold. The effect of temperature here is significantly greater than the effect of loading rate.Degree of crystallization Processing conditions (material degradation)To demonstrate these effects, test bars were milled from injection moulded sheets in the longitudinal and transverse directions and their mechanical property values were compared in a tensile testing machine (Fig. 4).In the case of 30% glass-fibre-reinforced PET, there was a strength loss transverse to the direction of flow of 32% for tensile strength, 43% for flexural modulus and 53% for impact strength. These losses must be taken into account in strength calculation by incorporating safety factors.A wide variety of reinforcing materials, fillers and modifiers are added to many different thermoplastics to alter their property profiles. In material selection, the changes in properties produced by these additives must be checked very carefully in brochures or databases (e.g. Campus) or, better still, technical advice should be sought from specialists employed by the raw material manufacturers (Fig. 5).Effect of moistureSome thermoplastics, especially PA6 and PA66, absorb moisture. This may have considerable effect on their mechanical properties and dimensional stability. Particular attention should be paid to this property in material selection (Fig. 6-7).Other selection criteriaOther requirements relate to processing considerations and assembly. It is also important to investigate the possibility of integrating several functions in one component so saving costly assembly operations. This measure can have a very beneficial effect on production costs. It can be seen that in price calculations, it is not only the raw material price that is important. It should also be noted that materials with higher rigidity permit thinner walls and so result in faster cycles.It is important to list all the criteria for material selection and evaluate them systematically.A rough material selection flow chart is shown in Fig. 8.Fig. 63.Wall thicknessAs much as necessary – as little as possibleWall thickness –In designing components made from engineering plastics, experience has shown that certain design points arise time and again, and can be reduced to simple design guidelines. One such point is wall thickness design, which has an important influence on component quality.Effect on specific component criteriaChanging the wall thickness of a component has a significant effect on the following key properties:–component weight–achievable flow lengths in the mould –production cycle time of the component –rigidity of the moulded part –tolerances–quality of the component in terms of surface finish, warpage and voids.Ratio of flow path to wall thicknessAt an early design stage, it is important to review the question whether the required wall thicknesses can be achieved with the desired material. The ratio of flow path to wall thickness has a critical influence on mould cavity filling in the injection-moulding process. If long flow paths combined with low wall thickness are to be achieved in an injection mould, only a polymer with relatively low melt viscosity (easy-flowing melt) is suitable. To gain an insight into the flow behaviour of polymer melts, flow lengths can be determined using a special mould (Fig. 1-2).Flexural modulus as a function of wall thicknessThe flexural rigidity of a flat sheet is determined by the material-specific elastic modulus and the moment of inertia of the sheet cross section. If wall thickness is automatically increased to improve the rigidity of plastic components without any thought given to the consequences, this can very often lead to serious problems with partially crystalline materials. In the case of glass-fibre-reinforced materials, changing the wall thickness also influences the orientation of the glass fibres. Close to the mould wall, the fibres are oriented in the direction of flow. On the other hand, in the centre of the wall cross section, random fibre orientation occurs as a result of turbulent flow.By increasing wall thickness, it is mainly the cross-sectional area of randomly oriented glass fibresparison of materials2.Material selection3.Wall thickness4.Ribbing5.Gate positioning6.Cost-saving designs7.General assembly technology 8.Welding technology 9.Tolerances 10.Check listGatehigh melt viscositymedium melt viscositylow melt viscositythat is enlarged. On the other hand, the thickness of the zone in which the fibres are oriented in the direction of flow remains largely the same (Fig. 3).This boundary zone, which critically determines component rigidity in the case of glass-fibre-reinforced plastics, is thus reduced in proportion to the overall wall thickness. This explains the decline in the flexural modulus (Fig. 4) when wall thickness is increased. The strength values determined on standard test bars (3,2 mm) are not therefore directly applicable to wall thicknesses deviating from this. To estimate component behaviour, it is essential to make use of safety factors. So by increasing wall thickness without consideration of the consequences, material and production costs are increased without a significant improvement in rigidity.Increase wall thickness?An increase in wall thickness not only crucially determines mechanical properties but also the quality of the finished product. In the design of plastics components, it is important to aim for uniform wall thickness. Different wall thicknesses in the same component cause differential shrinkage which, depending on component rigidity, can lead to serious warpage and dimensional accuracy problems (Fig. 6). To attain uniform wall thickness, thick-walled areas of the moulding should be cored (Fig. 5). In this way it is possible to prevent the risk of void formation and reduce internal stresses. Furthermore, the tendency to warp is minimized. V oids and microporosity in the component severely reduce its mechanical properties by cross-sectional narrowing, high internal stresses and in some cases notch effects.S 1 > S 0s 1s 1 > s 0s 0Fig. 3Fig. 4Fig. 5Fig. 64.RibbingOptimum rib designRibs –To overcome the problems that can arise with thick walls, ribs are an effective means of increasing rigidity while allowing wall thickness to be reduced.Generally, the rigidity of a component can be increased the following ways: –increasing the wall thickness–increasing the elastic modulus (e.g. by increasing reinforcing fibre content)–incorporating ribs into the design.If the required rigidity cannot be achieved in a design, the recommended next step is to choose a material with a higher elastic modulus than the original material. A simple way to increase the elastic modulus is to increase the content of reinforcing fibre in a polymer. However, given the same wall thickness, this measure produces only a linear increase in rigidity. A much more efficient solution is to increase rigidity by providing optimally designed ribs. Component rigidity is improved as a result of the increase in the moment of inertia. For optimum dimensioning of ribs, it is generally necessary to take into account not only engineering design considerations as such but also technical factors relating to production and aesthetic aspects.parison of materials2.Material selection3.Wall thickness4.Ribbing5.Gate positioning6.Cost-saving designs7.General assembly technology 8.Welding technology 9.Tolerances 10.Check listOptimum rib dimensionsIn rib design, a large moment of inertia can most easily be achieved by providing high, thick ribs. However, with engineering thermoplastics, this approach usually creates serious problems such as sink marks, voids and warpage. Furthermore, if rib height is too great, there is a risk that the rib structure will bulge under load. For this reason, it is absolutely necessary to keep rib dimensions within reasonable proportions (Fig. 1).To ensure trouble-free ejection of the ribbed component, it is essential to provide a demoulding taper (Fig. 2).Restricting material accumulationFor components requiring a very high quality surface finish, such as hub caps, rib dimensioning is important. Correct rib design reduces the tendency to form sink marks and thereby increases component quality.Material accumulation at the rib base is defined by the imaginary circle drawn in Fig. 1. By adhering to the dimensional proportions recommended there, this “circle” can be made as small as possible and sink marks can be avoided or reduced.If the imaginary circle is too large in this area of material accumulation, voids can be formed and mechanical properties drastically lowered as a result.Stress reduction at the rib baseIf a ribbed component is exposed to applied loads, stresses may be created at the rib base. If no fillet radii are provided in this area of the component, very high stress concentration peaks will build up (Fig. 3), which not infrequently lead to cracking and failure of the component. The remedy is to provide a sufficiently large fillet radius (Fig. 1) that will permit better stress distribution at the rib base. Radii which are too large, on the other hand, will also increase the diameter of the imaginary circle, which in turn can lead to the problems already mentioned.Choice of rib structureIn plastics design, a cross-ribbed structure has proved successful because it can handle many different loading permutations (Fig. 4). A cross-ribbed structure correctly designed for the anticipated stresses ensures uniform stress distribution throughout the moulding. The nodes formed at the rib intersections (Fig. 5) represent material accumulations but can be cored to prevent any problems. Care should also be taken to ensure that undue material accumulation is avoided at the point where the rib joins the edge of the component (Fig. 6)5.Gate positioningCorrect gate locationGate positioning –Besides causing processing problems, the wrong choice of the type of gating system and gate location can have a considerable effect on the quality of a moulded part. Design departments should, therefore, not underestimate the importance of gate location.Apart from carrying out design calculations for plastics parts, designers must pay particular attention to mould gating. They have to choose the correct gating system and the number and location of gating points. The different types of gate and gating locations can have a considerable effect on part quality.parison of materials2.Material selection3.Wall thickness4.Ribbing5.Gate positioning6.Cost-saving designs7.General assembly technology 8.Welding technology 9.Tolerances 10.Check listFixing the gate location also determines the following characteristics of a plastics part:–filling behaviour–final part dimensions (tolerances)–shrinkage behaviour, warpage–mechanical property level–surface quality (aesthetic appearance).Moulders have little scope to rectify the undesirable consequences of incorrect gating by optimizing processing parameters.Orientation determines part propertiesIn the injection moulding process, the long polymer molecules and fibrous filling and reinforcing materials are oriented mainly in the direction of flow of the polymer melt. This results in directional dependency (anisotropy) of the part’s properties. For example, strength properties in the flow direction are considerably higher than in the transverse direction (Fig. 1). Here the influence of the reinforcing fibres is significantly greater than the effect on strength of molecular orientation alone. Fibre orientation also causes differential shrinkage in the longitudinal and transverse directions, which can lead to warpage.Quality reduction as a result of weld lines and trapped airWeld lines occur when two or more melt streams unite in the mould. This happens, for example, when the melt has to flow around a mould insert or when parts are gated at several points (Fig. 2a+b). In addition, different wall thicknesses in a part can also lead to separation of melt fronts and so cause weld lines. Air entrapment (air bubbles) occurs when air that should be expelled from the mould is enclosed by melt streams and cannot escape. Weld lines and air entrapment are often manifested as surface defects. Apart from the fact that they are ugly, as a rule they also considerably reduce the mechanical properties in the affected areas, particularly impact strength (Fig. 3-4).defective partUnsuitable gate positioning has adverse consequencesAs gates always leave obvious marks, they should not be placed in areas which should have a high surface quality. In any gating region, high material stress (shear) takes place that considerably reduces the property levels of the plastics resin (Fig. 5). Unreinforced plastics have higher weld line quality than reinforced plastics. The quality-reduction factors in the weld line area are highly dependent on the type and content of filling and reinforcing material. Similarly, additives such as processing aids or flame retardants can have a detrimental effect. It is therefore difficult to estimate how much these factors will affect the part’s final strength. In addition, weld line areas with high load-bearing capacity under tensile stress do not show equally good impact strength or fatigue endurance. With fibre-reinforced materials, fibres in the weld line area are aligned transversely to the direction of flow. This significantly lowers the mechanical properties of the part at this point (Fig. 6).Fig. 3020*********%5-6040-900-1530-7020-8050-80Fig. 4Correct gate positioningComplex mouldings usually cannot be produced without weld lines. If the number of weld lines cannot be reduced, they should be placed in non-critical parts of the moulding in terms of surface quality and mechanical strength. This can be done by moving the gate location or by increasing/reducing part wall thickness.Basic design principles:–do not gate parts in highly stressed zones –avoid or minimise weld lines–avoid leaving weld lines in highly stressed areas–with reinforced plastics, gate location determines part warpage –avoid air entrapment by providing adequate vents.Fig. 6gatevoid6.Cost-saving designsLow-cost designsPrice as a Design Factor –The designer of a plastics component bears a large part of the responsibility for its final cost. His decisions essentially predetermine the costs of production, mould-making and assembly. Correction or optimization at a later stage is generally costly or impracticable.Influencing cost through material propertiesTaking full advantage of specific properties of plastics materials can help to save costs in many ways:Designs with multiple integrated functionsReduction in the number of individual parts through integration of several functions in one e of low-cost assembly techniquesSnap-fits, welded assemblies, riveted assemblies, two-component technology, etc.Exploitation of dry-running propertiesSaves the need for additional or subsequent lubrication.Elimination of surface treatmentsIntegral colour, chemical and corrosion resistance, electrical and thermal insulation properties.NucleationMaterials in the same product family can have different cycle times. The reason for this is a nucleating additive that accelerates crystallization of the melt during the cooling phase.parison of materials2.Material selection3.Wall thickness4.Ribbing5.Gate positioning6.Cost-saving designs7.General assembly technology 8.Welding technology 9.Tolerances 10.Check listInfluencing cost through finished-part designFurther cost reductions can be achieved, over and above those mentioned above, by observing the following points:Wall thicknessOptimized wall thickness distribution influences material costs and can reduce production time. MouldsTwo-plate moulds, reduction in the number of splits, etc.TolerancesExcessively high tolerance requirements increase the reject rate and quality control costs. MaterialsReducing cycle and cooling times through the choice of materials that set up rapidly, minimizing warpage problems by using low-warpage polymers (e.g. optimization of the ratio of mineral to glass-fibre reinforcement).Cost comparison broken down according to production cost componentsInjection-moulded parts should be ready for assembly as soon as they are ejected from the moulding machine, without needing any additional finishing operations. If finishing operations are required, the cost of plastics components often reaches that of metal designs (Fig. 1).Design determines production costsA general increase in wall thickness will not always lead to the desired strength increase in a component, but it will certainly mean a steep rise in production and material costs (Fig. 2). Partially crystalline thermoplastics undergo volume shrinkage as they set up. This shrinkage must be compensated for by continuing melt feed during the holding pressure phase. The approximate holding pressure time per mm wall thickness is, for example:–POM = 8 s–PA66 unreinforced = 4-5 s–PA66 reinforced = 2-3 s(Applies up to wall thickness of 3 mm)Examples of typical applicationsIn contrast to metal designs, which have to be machined and often pass through many assembly stages to turn out a single functional part, plastics technology offers considerable savings potential. In this example (Fig. 3), the guide and drive rods, spring, barbed-leg snap-fit element and bearing arrangement are injection-moulded in one piece. The equivalent metal design would require not only five individual parts that have to be assembled, but the rod would also need lubrication where it comes into contact with the stop. Choice of a POM homopolymer in fact made lubrication unnecessary at this point, too.Barbed-leg snap-fit designs in combination with integral hinges reduce the number of individual components, thus making assembly easier and thereby lowering costs. If brittle materials are used, another barbed-leg snap-fit element takes over the locking function if the integral hinge breaks (Fig. 4). In designing the part, the designer also necessarily defines the design of the mould cavity. He therefore determines the ejection system and the number of splits required. By judicious arrangement of undercuts, splits can be replaced by cores (Fig. 5).Fig. 3Fig. 4Fig. 5Fig. 1Snap-fit Assembly DesignThe great advantage of snap-fits is that with this technique no additional elements are needed to make the assembly.The most commonly used types of snap-fits in plastics technology are:–barbed-leg-type snap-fits–cylindrical snap-fits–ball-and-socket snap-fits.With all these snap-fit designs, designers must ensure that the geometry of the assembly allows the components to be as stress-free as possible after assembly to avoid stress relaxation, which would loosen the assembly with time.Basic design principlesThe design of a snap-fit assembly is determined by the permissible strain of the material to be used. Care should be taken with polyamide, for example, because in the dry state this material generally permits considerably lower strains than in the conditioned state. Glass fibre content also has an important effect on the permissible strain of the material and thus also on the permissible deflection of the barbed leg (Fig. 1).In a barbed-leg-type snap-fit, tapering of the deflecting leg reduces stress (Fig. 2). This design allows better stress distribution over the entire bending length. Stress concentration peaks at the base of the leg are less and assembly forces are considerably reduced.Failure to radius the junction between the base of the barbed leg and the main body of the component, or to provide sufficiently large radii in this area, often results in weak points. In principle, a sufficiently large radius should be provided to avoid stress concentration peaks. Cylindrical and ball-and-socket-snap-fits often have to be slotted to facilitate assembly; in this case the slot end must not be designed with a sharp edge.Press-fit AssembliesPress-fits enable high-strength assemblies to be made between plastic components at minimal cost. As with snap-fit assemblies, the pull-out force of a press-fit assembly decreases with time as a result of stress relaxation (Fig. 3). Design calculations must take this into account. In addition, tests with the expected service temperature cycles must be carried out to confirm the feasibility of the design.Threaded Assemblies Array Threaded assemblies can be produced with thread-cutting orthread-forming screws, or by the use of integrally mouldedthreaded inserts. The flexural modulus of the material to beused provides a good guide to the type of threaded assemblythat is most appropriate. For example, up to a flexural modulusof about 2800 MPa, thread-forming screws may be used.Metal inserts must be used if metric screws are required or ifthe threaded assembly is intended to be undone several times.To prevent premature component failure, it is important toensure correct dimensioning of the boss (Fig. 4). Screwmanufacturers give recommendations on this.Screws with a tapered countersunk head should as a generalrule be avoided in plastics assembly technology since theresulting forces (Fig. 5) cause the screw hole to “splay out”.One possible result of such additional stress is that weld linescan easily rupture.8.Welding technologyThe Best Assembly Techniques –Part IIWelding technology – In addition to the assembly techniques described in article 7 of this series, many different welding methods can be used to join plastic parts. To ensure low-cost, functionally efficient designs, it is necessary to select a suitable welding method and give careful thought to the required joint geometry at an early stage in the design process.parison of materials2.Material selection3.Wall thickness4.Ribbing5.Gate positioning6.Cost-saving designs7.General assembly technology 8.Welding technology 9.Tolerances 10.Check listair-intake hose (inserts)air-intake pipebodyrunner jointscigarette lighterFig. 1Welded joints are assemblies for permanently connecting plastics parts without additional assembly elements. The choice of welding method depends on several criteria: the geometry of the moulded part and on the materials used, on cost-effectiveness, suitability for integration into the overall production cycle and the mechanical and aesthetic quality requirements for the assembly zone. Different welding methodsThere are many different, cost-effective welding methods suitable for industrial mass production. The methods most frequently used for plastics engineering components are (Fig. 1):–hot-tool welding–spin welding–vibration welding–ultrasonic welding.Other methods worth mentioning include:–high-frequency welding–induction welding–hot-gas welding.New methods are also being developed (e.g. laser welding), but these are not yet widely used in industry.In all these methods, the assembly operation is carried out by applying heat (melting the surfaces to be joined) and pressure. Heat can be generated directly by contact or radiation, or indirectly by internal or external friction, or by electrical effects.Choosing the right methodTo achieve good, reproducible weld quality, it is necessary to choose a suitable welding method, optimize welding parameters and ensure that the parts to be assembled are correctly designed for the welding method being used. Welding machinery manufacturers supply not only standard equipment but also various special welding units to cater for a wide variety of welding tasks. Before deciding on a welding method, it is advisable to consult the machinery manufacturers or resin suppliers. Different welding propertiesTheoretically, all thermoplastics are weldable, but the welding behaviour of plastics differs considerably in some cases. Amorphous and semi-crystalline polymers cannot be welded together. Plastics that absorb water (e.g. nylon) need to be pre-dried, since moisture leads to poor-quality welds. For best results, nylon parts should either be welded immediately after injection-moulding or kept in a dry state before welding. Resin additives such as glass fibres and stabilizers can also influence welding results. Welded assemblies of unreinforced plastics can attain weld factors close to the strength of the parent material, given suitable process parameters and part design. With glass-fibre-reinforced plastics, loss of strength due to fibre separation or reorientation in the welding zone must be taken into account.Correct weld designAn essential requirement for high-quality welds is suitable design of the weld profile. The profiles shown in Figures 2 and 3 have proved successful basic designs. If the weld zone additionally has to meet high aesthetic specifications, then special geometry is needed. The diagrams show possible ways of hiding flash by providing recesses to absorb the excess material (Fig. 4). Thin-walled parts need to be designed with a guided fit into each other, so that the necessary welding pressure can be applied without the walls moving out of alignment.。

塑料模设计与制造指导手册范本

（部讲义）编著：兆飞审核：模具教研室铁路职业技术学院机械与电子工程学院模具教研室目录第一单元热塑料制品设计原则 (4)一、尺寸、精度及表面粗糙度 (4)1、尺寸 (4)2、精度 (5)3、表面粗糙度 (6)二、形状 (6)三、脱模斜度 (7)四、壁厚 (8)五、加强筋 (8)六、支承面 (9)七、圆角 (10)八、孔（槽） (10)九、螺纹 (11)十、嵌件 (13)十一、标记、符号、图案、文字 (15)第二单元塑料模设计原则与查验 (17)一、塑料模具设计原则 (17)1、模具设计上应与热交换器相似 (17)2、采用平衡式流道系统 (18)3、模具设计标准化 (18)4、足够的排气装置 (18)5、确保快速修模，设计时预留修模量 (18)6、以容易组立，不易出错为原则 (18)7、以模具易加工，精度适当为原则 (18)二、模具设计要项查检 (19)（一）注塑模具设计之计算公式 (19)（二）注塑模具结构设计 (20)第三单元塑料模具设计流程 (23)一、方框图 (23)二、流程表 (24)第四单元塑胶模具制作规 (28)一、确认图面 (28)二、模具制作流程 (29)三、试模前务必完成下列之确认 (29)第五单元注射模设计实例 (31)一、注射成型工艺规程的编制 (31)1、塑件的工艺性分析 (31)2、计算塑件的体积和重量 (32)3、塑件注射工艺参数的确定 (32)二、注射模的结构设计 (32)1、分型面选择 (32)2、确定型腔的排列方式 (33)3、浇注系统设计 (33)4、抽芯机构设计 (34)5、成型零件的结构设计 (34)三、模具设计的有关计算 (34)1、型腔和型芯工作尺寸计算 (35)2、型腔侧壁厚度和底板厚度计算 (35)四、模具加热与冷却系统的设计 (37)五、注射机有关参数的校核 (38)六、绘制模具总装图和非标零件工作图 (38)第六单元模具制造实例 (41)一、模具总体工艺流程图 (41)二、注射模主要零件加工工艺规程的编制 (42)三、模具装配工艺流程编制 (43)四、模具试模、调试与验收 (45)1 试模的目的与要求 (45)2 塑料模具的试模与调整 (46)3、塑料注塑模具的验收 (54)《塑料模具设计》课程设计指导书 (56)第一章概论 (57)一、课程设计的目的 (57)二、课程设计的选题 (57)三、课程设计基本要求 (57)四、设计前的准备工作 (57)五、设计步骤及注意事项 (58)六、设计任务 (58)七、设计参考资料 (58)八、设计时间及学时安排 (58)第二章注射模具的设计程序 (59)一、接受任务书 (59)二、收集整理资料 (59)三、注射成型制品的分析 (59)1、消化塑料制件图 (59)2、塑料成型工艺分析 (59)3、明确制品的生产批量 (59)4、计算制品的体积和重量 (60)四、选择成型设备 (60)五、拟定模具结构方案 (60)六、绘制模具装配图和零件图 (60)七、校核模具图样 (60)八、编写模具设计计算说明书 (60)第三章注射模具设计及模具图绘制 (61)第一节模具结构设计 (61)一、模具的基本结构 (61)二、注射模具设计的基本容 (61)三、注射模具设计的有关计算 (62)四、模具零部件的设计 (62)第二节模具图的绘制与校核 (62)一、装配图要求及绘制方法 (62)二、零件图要求及绘制 (64)三、审核设计结果 (65)第四章模具设计计算说明书的编写 (66)一、设计计算说明书的容 (66)二、设计计算说明书的要求及格式 (67)附件1：封面 (69)附件2：《塑料模具设计》课程设计任务书 (70)附件3：学院注塑机主要技术参数： (71)附件4：模具制造毛坯尺寸余量设计参考： (71)第一单元热塑料制品设计原则一、尺寸、精度及表面粗糙度1、尺寸这里的尺寸是指制件的总体尺寸，而不是壁厚、孔径等结构尺寸。

外国工程师传授的design资料

外國工程師傳授的design資料，供大伙儿享受。

Injection Molding Design Guidelines注塑模具设计指导Much has been written regarding design guidelines for injection molding. Yet, the design guidelines can be summed up in just a few design rules.已经有许多关于设计注塑模具的书了,可是设计准那么能够被归纳以下几点:Use uniform wall thicknesses throughout the part. This will minimize sinking, warping, residual stresses, and improve mold fill and cycle times.1.零件整体壁厚维持均匀.如此能够最小化缩坑,翘曲,强度减小,模具填充和循环时刻.Use generous radius at all corners. The inside corner radius should be a minimum of one material thickness.2.在转角处大量采纳圆角.圆角内部最小半径为一个壁厚.the least thickness compliant with the process, material, or product design requirements. Using the least wall thickness for the process ensures rapid cooling, short cycle times, and minimum shot weight. All these result in the least possible part cost.3.依照工艺,材料,产品设计需求.采纳最小壁厚.最小壁厚的应用能够确保外國工程師傳授的design資料，供大伙儿享受。

塑胶件设计准则(一)

塑胶件设计准则(一)随着塑料工业的迅速发展，塑胶制品已经成为生产制造业中不可或缺的一部分。

然而，在进行塑胶件设计时需要考虑多方面的因素，这些因素决定了产品的使用寿命、质量和成本。

本文将介绍塑胶件设计准则，以帮助读者更好地了解如何进行塑胶件设计。

1.材料选择在设计塑胶制品时，首先需要选择适合的塑料材料。

不同的材料具有不同的特性，例如抗拉强度、刚度、耐热性等。

选择材料的时候，需要考虑产品的使用环境和工作要求，以确保最终产品符合需求。

2.几何设计几何设计是塑胶制品成功的关键之一。

正确地设计产品的弯曲角度、半径和厚度等等是至关重要的，因为它们直接影响产品的可靠性和稳定性。

产品的自洁能力、防裂性和其它特性也与几何设计相关。

3.融合融合是塑胶件设计中的另一个关键因素。

在生产过程中，需要考虑良好的融合，这将直接影响产品的质量和强度。

一般来说，在处理过程中要确保塑料的速度和温度是恰当的，使产品外观平滑、无瑕疵，并且强度更加均匀。

4.尺寸精度产品的尺寸精度对于高质量的产品制造非常重要。

在设计和生产过程中，必须严格控制尺寸精度。

如果精度过低，往往会影响产品的可靠性和性能。

5.模具设计加工模具的质量将直接影响成品的质量。

因此，在设计模具时，需要充分考虑产品的要求，并尽可能减少缺陷的可能性。

从模具材料的选择到处理方法的选定，都必须被考虑到。

综上所述，塑胶件设计准则是非常重要的，可以确保产品质量和性能。

设计师需要仔细考虑产品使用的工作条件，选择适合的材料，并采取正确的几何设计方法。

保证良好的融合、尺寸精度和模具设计，可以使塑料制品达到最高质量标准，从而满足用户的需求。

塑胶产品设计designing with plastic

74
9.1.4 Assembly with Fasteners
75
9.1.4.1 Bolted Assembly
75
9.1.4.2 Threaded Metal Inserts
77
9.1.4.3 Self-Tapping Screws
78
9.1.4.4 Riveted Assembly
78
9.1.4.5 Sheet Metal Nuts
1
Physical Properties
and Terminology
2
Mechanical
Properties
3
Thermal
Properties
4
Electrical Properties
5
Environmental
Considerations
6
Structural
Analysis
7
Design Considerations for
1.
Plastics Materials – An Overview
10
1.1 Classification
11
1.1.1 Thermoplastics
12
1.1.2 Thermosets
12
1.1.3 Crystalline, Amorphous, and Liquid
13
Crystalline Polymers
13
1.1.4 Copolymers
14
1.1.5 Alloys
14
1.1.6 Elastomers
14
1.1.7 Additives, Reinforcements, and Fillers

《塑胶产品相关设计》讲义

Wall Thickness, Rib
Conventional
0.080 to 0.125 in (2.0 to 3.2 mm)
trib 0.6 twall h 4 twall r 0.375mm

1o 2
Thinwall:
0.050 to 0.080 in (1.2 to 2.0 mm)
(1.2 mm)
tboss 0.6 twall twall
h 4 twall
r 0.375mm 0.6 *twall

1o 2
1o
OD 2 ID
tboss twall h 4 * twall r 0.6 *twall
1o
OD 2 ID
壁厚設計 Wall Thickness Design
差 [Poor]
較好 [Better]
最好 [Best]
掏空設計(1) Coring Out Design (1)
原設計 [Original]
改進設計 [Improved]
掏空設計(2) Coring Out Design (2)
差 [Poor]
L H
A'
A'
KE
JD F
I
G
A C
B
Section A'-A'
A =凸轂附著處壁厚
wall thickness B =凸轂外環直徑
dia. of boss over radii C = 0.5 A D =2B E = 1 ~ 2 deg F = 0.13 mm ( radius ) G =D H = 0.8 A I =A/4 J =2B K = 0.3 ~ 1 J L = 0.5 A

第5部分：塑胶件设计指南

原始的设计
优化的设计
11
1.零件壁厚
C. 零件壁厚均匀
当壁厚不均匀时：原始的设计
较好的设计a
较好的设计b
优化的设计
DFMA
12
2.避免尖角
A.避免零件外部尖角
DFMA
原始的设计
优化的设计
例外：零件分模线处直角的设计比较好
原始的设计
优化的设计
13
2.避免尖角
B.避免在塑胶熔料流动方向上产生尖角
39
8.提高塑胶件外观的设计
D.设计美工沟：
原始的设计美工沟的设计之一美工沟的设计之二
DFMA
40
8.提高塑胶件外观的设计
DFMA
E.避免外观零件表面出现熔接痕：
塑胶件表面咬花可以部分掩盖熔接痕，但并不能完全掩盖熔接痕；喷漆可以掩盖熔接痕；合理设置浇口的位置和数量，避免在零件重要外观表面产生熔接痕；保证模具通风顺畅。
二．塑胶件设计指南
1. 零件壁厚 2. 避免尖角 3. 脱模斜度 4. 加强肋的设计 5. 支柱的设计 6. 孔的设计 7. 提高塑胶件强度的设计
DFMA
8. 改善塑胶件外观的设计 9. 降低塑胶件成本的设计 10. 注塑模具可行性设计
三．塑胶件的装配
1. 卡扣装配 2. 紧固件装配 3. 超声波焊接
分类非结晶塑胶结晶塑胶比重较低较高拉伸强度较低较高拉伸模量较低较高延展性较高较低抗冲击性较高较低最高使用温度较低较高收缩率和翘曲较低较高流动性较低较高耐化学性较低较高耐磨性较低较高抗蠕变性较低较高硬度较低较高透明性较高较低加玻璃纤维补强效果较低较高材料特性塑胶分类dfma一
DFMA
第5部分塑胶件设计指南 Design for Plastic Guidelines

塑胶件设计指导

塑膠件設計指導P1/11part 1 Prepared & Reviewed by : CL Tong.一. 通孔和盲孔的設計 Date: 16-OCT-001. 尺寸要求○1 對於盲孔的設計. 見下圖:max 1D( D<1.5 mm ) 圖一圖二圖一, 盲孔的深度應不大於孔內徑的2½倍. 當孔內徑D 小於1.5mm 時, 其盲孔的深度應設計成最大不能超過1D.○2 對通孔的設計用型芯來成型通孔. 孔的上下兩部分可以允許其一有稍微的超差. 即使裝配時有些許失配 (建議設計方案如圖三)圖三2.注意問題○1 通孔的內面, 外面在壓制成型時易出現毛邊. ○2 盲孔底部要有一定的圓角及其要有一定的錐度, 以利於脫模. ○3 在垂直於脫模方向上應避免側孔. 二. 加強筋設計1.2. 設計要求: 2T 如下圖)圖四P2/11 圖四中, 加強筋根部的厚度應不大於所要加強部分壁厚T, 筋高度應大於3T, 而筋與筋之間的距離(筋中心線與筋中心線之間) 應大於2T.3.注意問題○1多根加強筋設計其效果優於單根加強筋(即使你增大其厚度或高度)○2筋的根部要有一定的圓角, 要有一定的錐度, 以利於脫模.○3加強筋的方向應跟模壓, 成型, 熔料流動方向相一致.三.击台1.目的: 增強孔的穩固及強度或裝配附件之用.2.設計要求圖五圖六击台高度最大不超過击台根部尺寸D的二倍, 击台根部外徑與內徑之差的一半應為0.8T如圖五. 击台跟平面相裝配時, 击台須設計在成型件的四周. 且其高度如圖六所示應為0.4mm. 如果A外平面的平面度要求較高. 還需要打磨.3.注意問題○1击台根部要有一定的圓角和其要有一定的錐度, 以利於脫模.○2當击台高度過高時, 可在击台外部加加強筋, 不僅可以增大击台強度. 而且還有利於促進熔爐塑料的流動.四.錐度設計1.含義: 由於成型時零件內外表面收縮率不一致, 在設計時, 根據塑料對型蕊的粘附力要大於對型腔的粘附力, 設置內表面錐度大於外表面錐度.2.注意問題○1成型件設計要有一定錐度是有利於脫模.○2同樣有利於減少成型過程中瑕疵的形成.五.螺紋的設計(熱固性塑料)塑料螺紋包括螺紋孔和螺牙.1.如下圖○1螺牙要圓, 不宜尖.○2螺紋長度要短.2.如下圖P3/11, 螺紋的中心線位於分型面上.3.螺牙角選擇為32º4.採取成型後再加工螺紋方式去獲取塑料螺紋.5.當螺紋孔要多次裝配時, 建議使用內嵌件.六.嵌件1.要求:○1在塑膠件成型之後. 立即把嵌件壓制到膠件上. 讓包圍著嵌件的部分收縮而來緊嵌件.○2外部嵌件會因為合成物料的收縮而松軟, 內部嵌件會因它的收縮而破裂. 所以在設計嵌件時應考慮配套零件的壁厚,嵌件包圍部分壁厚設計參考表6.1-3.(略)2.注意問題○1用模具壓制嵌件時, 易出現嵌件由於圍壁出現收縮而松動又或者壁易出現斷裂現象.七.平面度由於在成型時易混入氣泡等使熱固性塑料出現收縮現象. 要獲得良好的平面度十分不易的. 通常要求表面留有0.3%的余量.八.零件圖:最終零件圖要指出, 哪一個地方不可以出現分型線. 不可以出現澆口痕, 哪一個地方需要印上模號和模具標記. 哪一個表面出現缺點不能接受等等. 使用SPI/SPE的配套完模工具作為指導.這樣做的目的是易於發現問題和解決問題.九.尺寸因素熱固性塑料成型件尺寸精度可以達到要求公差. 但是, 其精度難以跟加工金屬零件相提並論.造成這樣的原因是:1.塑膠料的收縮率(在成型中).2.成型後塑膠料的收縮率.3.時間, 溫度, 壓力(成型條件)4.模具類型.5.射出及預成型尺寸.6.熔料的流量變異.7.塑膠料種類.十.公差尺寸公差表參考表6.1.4(略)P4/11PART 2一. 注射成型過程○1粒狀塑膠料加入到料斗在180℃高溫下隔熔成液體狀. (熔化的溫度同塑膠料的種類和成型條件有關) 進入鋼模, 被水冷卻成固體狀(水在模外) 取零件.○2整個過程周期為45秒. 壓力為70,000Kpa, 大部分時間用於冷卻.二. 注射成型件的典型特徵及發展趨勢.注射成型適用於大批量複雜零件的生產. 雖然其仍然有極多局限性, 但由於一個注射成型產品可以代替裝配出來的產品, 所以, 其經濟性很好, 另外, 由於顏色, 形狀可以一次性成型做到, 免去二次加工.○1主要特徵:I. 廣泛應用於薄壁零件, 但也可以成型大塊及不同壁厚的零件.II. 強度低, 適用於外殼, 連接桿等受力較小的場合.○2發展超勢熱塑性材料強度會變得越來越大, 機械特性越來越好, 一些類似尼龍, 複合碳酸鹽等,其強度可以同鐵, 鋁, 甚至鋼相比美.PART 3 P5/11一. 收縮率的影響1.啤模時會產生許多不規則或拗曲的形狀, 常見的有夾水紋, 縮水等, 它們常發生在零件較厚的部位.(如圖七)圖七2.另一種經常產生的缺限就是“U”型楔面收縮(如圖八). 第三種情況就是在左右平面收縮變形. (如圖九) 方向易產生平面出現固收縮而引起的曲線.圖八圖九二. 經濟的生產數量注射模適用於量生產的, 一般不會用此方式, 除非有上萬或者更多零件要生產. 之所以有此限製是因為每種零件都需做一個自己獨有的模.只有大量生產開模的經費才能在批量生產中收回, 即便是很小的零件都要花幾千元的開模費. 那些較大較複雜的零件就更會花上萬乃甚至十萬元的經費.三. 合適的原料多種合適的熱熔膠可用於注射模生產. 常用的有聚乙烯﹑PVC﹑尼龍﹑ABS﹑等.注射模在熱塑模市場有很重要的地位, 因此工程人員必須設法使之更利於生產. 物理特性及價格常是選擇這些材料時比加工性能更為重要的因素.通常, 高性能的工程塑料往往比日常使用的塑料像PE料, PP料, PS料等之類更難開模, 特別是PVC雖具有價廉和高性能的優點, 但卻比一般塑膠更難注塑, 最主要的缺點是它的熔點到凝固溫度範圍太窄.表6-2-2列出了一些常用的注塑材料及其特性, 價格和使用範圍. (略)四. 設計指南1.水口及頂針位:設計者須考慮它們的方位, 因為它們會對表面成型產生影響. 如果注件有內外側的話, 水口常開在下側. 水口一般的方位見圖6-2-6(略) 圓形或圓柱型注件的中央水口或者近於中央水口(較大面積的注件)在注塑時是最理想的安全模塑頂料方式.2.注件厚度:表6-2-3 列出了注件厚度的正常值及下限(略), 表明了塑料在注塑完工以前它在模件中冷卻和固化的趨勢, 塑料流動愈緩慢, 則注件厚度要求愈窄, 當然注件的厚度要盡可能的一致. 即便是不得已要改動厚度, 最好變動要舒緩, 不突變.(如圖十)圖十P6/11錯誤設計正確設計錯誤設計稍好設計最好設計3. 孔的設計● 注塑件開孔雖可行卻是開模最複雜的一個因素. 孔周圍易產生飛邊以及 “夾紋” 或是 “夾水weld line圖十一●兩孔間距或是孔到邊的距離至少要有一個孔徑. (如圖十二)錯誤設計正確設計圖十二●為避免外應力的影響,單孔必須開在距注件邊緣三個或以上孔徑的地方.(如圖十三)P7/11正確設計錯誤設計圖十三●通孔較盲孔好, 因為做孔所用到的頂針可以在兩頭加以固定, 這樣做出的孔位置尺寸很標準而且可以避免彎曲或折斷.●在注件底部開孔較在邊上開孔好, 因為後者須要可折卸頂針.●盲孔深度須小於兩孔徑之和, 若孔徑為1.5mm或更小, 那麼其深度最小應有一個孔徑. (如圖十四)大孔小孔圖十四●利用击台可以增加盲孔深度, 這須用到較硬的頂針(型蕊). (如圖十五)錯誤設計正確設計圖十五●切去通孔零件兩端的部分可縮短頂針(型蕊)的長度. (如圖十六)錯誤設計正確設計(此設計可降低心棒受損危險性)圖十六4.加強筋●加強筋必須比注件的厚度薄一些, 防止注件表面縮水. 比較好的方法是保證加強的寬度為注件厚度的一半或更少.P8/11●同樣為避免縮水, 加強筋高度須不大於壁厚的1.5倍.●如果有必要, 可以用兩個筋位去加強注件強度用以代替一個更高的筋位的作用.這些筋位須以兩個或以上壁厚的距離分散開來.●為使注件順利地從模中取出, 加強筋必須與注件方位垂直.●由加強筋引起的縮水可以通過在其對面增加凹槽的方法加以減輕和去除. (如圖十七)蝕紋錯誤正確正確正確圖十七●加強筋的設計規則如圖十八.錯誤設計正確設計5.击台: 主要用於塑件的表面突起.●它必須有較大的半徑和圓角.●在加強筋中說明過的原則同樣適用於击台一節. 圖十九表明了固體击台的最大高度和寬度.圖十九●如果可能, 將击台做至邊角處可有助於充模時塑料的流動, 若有必要, 在做可拆裝的击台時,加個聯接筋位將有助於塑膠充模.●如果可能, 盡力避免在罐上部做击台, 因為這將會產生更多氣泡.P9/11●在击台上採用5°錐度, 其設計與加強筋相同.●如果較大的击台要用到, 那必須是中空, 且與塑件厚保持一致.6.凹槽凹槽在注塑中同樣會用到, 只是他們要用到滑動型蕊和分模方式, 凹槽可開在注件的分型線或其延長線方向上, 以避免型心的拉力作用. 凹槽可以不依靠型蕊的拉力即可較容易的脫模. 如果凹槽被移除, 則另一半模必定會保持完好. 那麼頂針(型蕊)將被用於脫模. 凹槽的一般設計尺寸如圖二十.7.螺紋設計螺紋成型盡管很複雜, 但卻是可以辦到的可使用以下三個方法:●螺紋成型後使用旋轉型蕊. 可以使模件順利地從模中取出.●令螺絲軸線與分型面一致. 這樣可避免用到旋轉型蕊, 且可以在模型間得到更好的配合以減少螺紋上的流痕. 這種方案僅用於外部螺紋制作, 且成本昂貴, 除非螺紋可以遠離分型面,而通常這也是可行的. 如果這種方法不適用, 另一種可能的方式將被要求用來移除分型面在螺紋上產生的流痕.●減少螺紋齒數, 降低螺牙高度, 零件可以直接從模腔中脫出而不須從製品中擰下來. 螺牙未端不宜延長到與垂直底面相接處, 否則易使脆性塑料件發生斷裂, 螺紋的始端均不應突然開始和結束, 而應有過渡部分. 因為它方便取出而且避免了多余的飛邊, 以致模件很難配合,甚至生成流痕. 如果是剛性螺紋, 必須使用金屬模蕊.P10/11PART 4原始設計改善設計(增強強度)有時候為了確保產品具有足夠的強度有必要修改設計方案. 防止縮水方法之一是在部件易於受影響的表面加鋸齒狀的骨位.標準的外形為模具工業的發展所需要, 因為它便宜, 且易於採購. 如果有仍何可能我們寧可用標準件, 這對於大現模生產尤其顯得重要.※擠出材料熱熔物的選擇非常重要, 特別是對一種新技術, 新產品. 高強度的苯乙烯是一種最易擠出的塑膠, 纖維與丙烯居其次, 最難擠出的材料為尼龍. 軟塑料不如硬塑料易於擠出到一個細小公差, 快速冷卻會產生內應力並導致裂紋生成. 透明材料(如: PE; 尼龍; VC和PP)常在冷水中冷卻.通過不平衡壓模ABS和PS較PE, PP料易擠出成型. 後者比前者具有更低的熔解強度和更易改變的條件(測試條件易控制).如果採用“雙料擠塑”的材料不同, (除外)那它們之間的結合可能是不完整的. 完全不同的材料連接在一起要通過凹槽. 燕尾槽或機械連接. 當要對不同的塑料作雙料擠塑時一定要考慮材料間的相容性.例如: 增型擠塑乙烯基就與PS不相容.※材料的特點:1.ABS--- 硬性好, 易出模可調任何顏色. 可塑出任何複雜外形. 公差控制水平較高. 用於房屋, 門柱手柄等.2.CA--- 價廉, 通用硬性要求高或較高產品. 顏色可任何意調製. 耐氣候性差, 須涂上防護油, 汽油和大量清潔液體. 易清洗, 斷面較薄.3.CAB--- 與2 類同,但有更好的耐熱與氣候浸蝕性氣味難聞. 顏色可隨意配製, 用於標志倍存.4.CP--- 與3相似只是沒有怪味.5.EC--- 硬性彈性好, 易出模. 公差易控制. 低溫下穩定. 用於膠管刀刃及裝飾部件.6.EV A--- 柔性好, 可配製任何顏色. 外形單調. 用於低性能小五金. 印章, 墊圈等.7.尼龍--- 體輕, 很高的延伸性, 僅用於較單一的外形產品. 對公差要求不高. 凝固速度快. 很好的吸水性. 用於膠管, 路標, 摩擦溝道等.8.PC--- 最好的整體平衡性. 用於製造標準的外形. 公差控制容易. 較貴. 須特別處理, 但其吸水性,導熱性差. 用於燈罩, 消毒櫃等.9.PE--- (高密度)比低密度的PE更加堅硬, 公差難控制. 用於皮帶, 棍棒等.10.PE--- (低密度)較軟, 難以成型. 很好的非導電性,室溫下即能溶解. 用於膠管, 手柄, 緩沖器等.11.PP--- 很輕,標準公差控制. 不適用於複雜的外形. 可調多種顏色. 用於高性能絞鏈樞扭, 滑動導架等.12.PS--- 價廉, 適用於任何顏色, 易碎, 擠塑有限製. 用於燈罩等.13.PS--- 高彈性, 堅硬, 低價. 用於複雜外形. 標準公差控制. 顏色不限. 用於滑動門的導架等.14.PVC--- (柔軟) 通用於各種硬度. 標準的複雜外形. 標準的公差控制.用於各種顏色, 常用於進氣口, 密封圈.P11/1115.PVC--- (硬) 易出模, 可用於複雜外形, 優良的非導電性特性.公差控制容易. 有顏色限製. 常用於導電體的殼和蓋.16. PN--- 可用於各種硬性可調出, 用於各種顏色. 耐磨性好, 常用於傳送帶.17. VD--與15相似. 其非導電特性比PVC(硬)更加好. 複雜的外形, 優良的公差控制特性. 可擠塑出任何顏色. 用於製做熱水管, 高溫涂藥器等.PART 5一.影響尺寸的因素:盡管模塑零件能夠保證這種變異的緊配合公差, 但是對可獲得一定精度的金屬零件之尺寸卻不能保證原因有以下幾種:1.材料收縮力, 包括材料收縮過程中的均勻和不確定性.2.塑料有高的熱膨脹系數, 因此, 如果公差定得過大或過小, 設計者就應定出溫度並采取測量措施.3.盡管有對壓力, 溫度, 時間設定作自動調節的設備, 但這些因素在從一次注塑到另一次注塑間都會有一些變化, 這些變化的結果導致模塑零件輕微的尺寸變化.4.塑料零件通常較金屬零件有較大的柔軟性.由於柔軟因素的存在使得塑膠零件的緊配合無多大必要. 裝配時, 如果有必要去確保一個好配合常可通過零件輕微的變形達到. 如有必要, 明智的設計者可利用設計塑膠零件的击台和击緣去確保與相配零件表面的對稱.與其它過程相比, 緊配合會大大的增加注塑模零件的成本, 精密(公差)模具比粗製(公差) 模具的成本更高, 正如當零額外的緊配合時就會導致加工成本的增加, 例如, 須為壓力, 溫度和循環時間增加相關過程控制, 因而也許會增加循環時間或需要膠件出模後的熱套裝置, 廢品率也更高.不同的塑料材料有不同的公差特性, 低收縮率材料能以相應公差被恆定的注塑, 玻璃或礦物填充材料的注塑比非填充材料更精確. 更多模腔數的使用導致降低所注塑零件控制尺寸的精確. 根據以往經驗, 對每個模腔在第一次啤塑之後的尺寸允差都應增加5%, 例台, 一單模腔在某一尺寸具有±0.1mm的允差;在模腔長為10應有±0.15mm (0.006in) 的允差(公差增加10x5percent=50%).表 6.2.4(略)及6.2.5(略)為不同塑料材料的尺寸公差的建儀值, 這些表格數據, 是由塑膠工業行業提供數據所歸納出的. 代表了以往和現在塑膠模工業的發展成果, 個別模廠的合同形式和協議所規定的也許有變化.。

塑件设计指南

目录第一章塑件设计的一般程序和原则 (1)1.1 塑件设计的一般程序 (1)1.2 塑件设计的一般原则 (1)第二章塑件的收缩 (1)第三章拔模斜度 (4)3.1拔模斜度确定要点 (4)3.2 制品拔模斜度设计 (5)第四章制品壁厚 (7)4.1制品壁厚的作用 (7)4.2 制品壁厚的设计 (7)第五章加强筋(含凸台、角撑) (12)5.1 加强筋的作用 (12)5.2 加强筋的形状及尺寸 (12)第六章支承面 (17)第七章圆角 (18)第八章孔 (19)8.1 制品孔的形式及成型方法 (19)8.2 孔的模塑成型 (20)8.3 孔的设计要点 (23)第九章侧面凸凹和侧孔 (26)9.1 制品的侧凸凹 (26)9.2 侧凸凹的设计与成型方法 (27)第十章螺纹 (31)10.1 塑件螺纹的类型与选用(图2—54) (31)10.2塑件螺纹的模塑成型方法 (32)10.3 塑件螺纹设计要点 (32)第十一章塑件中的嵌件 (35)11.1 嵌件的结构形式 (36)11.2 嵌件在塑件中的固定 (38)11.3 嵌件在模具中的安放与定位 (40)11.4 嵌件周围塑料的裂纹和联接强度 (42)11.5 装配式嵌件（制品模塑后再装入嵌件） (43)11.6 塑料嵌件（嵌件的外插注射模塑） (44)第十二章塑件的凸凹纹（滚花） (45)第十三章标记、符号 (47)第十四章制品的尺寸精度 (47)14.1 尺寸精度的组成及影响因素 (47)14.2 塑件尺寸公差 (49)附录一：塑料的基本概念及其常用工程塑料的性能特点 (52)附录二：塑料的成型工艺 (55)塑件设计指南塑件的结构设计又称塑件的功能特性设计或塑件的工艺性。

第一章塑件设计的一般程序和原则1.1 塑件设计的一般程序1. 详细了解塑件的功能、环境条件和载荷条件2. 选定塑件品种3. 制定初步设计方案，绘制制品草图（形状、尺寸、壁厚、加强筋、孔的位置等）4. 样品制造、进行模拟试验或实际使用条件的试验5. 制品设计、绘制正规制品图纸6. 编制文件，包括塑件设计说明书和技术条件等。

Design Guides for Plastics

Special featial techniques
Extrusion .......................................................................................... Blow moulding .................................................................................
Thermoforming ................................................................................
April 2006
April 2006
Preface
This set of hints and tips for plastics product designers is intended as a source book and an 'aide mémoire' for good design ideas and practices. It is a source book for plastics product designers at all levels but it is primarily aimed at: student designers carrying out design work for all levels of academic studies; • non-plastics specialists involved in the design of plastics products; • plastics specialists who need to explain their design decisions and the design limitations to non• plastics specialists. The book covers each topic in a single page to provide a basic reference to each topic. This space constraint means that each topic is only covered to a basic level. Detailed plastic product design will always require detailed knowledge of the application, the processing method and the selected plastic. This information can only be provided by raw materials suppliers, specialist plastics product designers and plastics processors but there is a need to get the basics of the product design right in the first instance. Using the hints and tips provided in this guide will enable designers to reduce initial errors and will lead to better and more economic design with plastics. I hope this short work will improve the basic design of plastics products and if it can do this then it will have served it’s objectives.

塑料件设计要求共80页文档

1、塑件上螺纹成型可用以下三种成型方法 ①模具成型 ②机械加工制作 ③在塑件内部镶嵌金属螺纹构件。 2、模塑螺纹的性能特点： ①模塑螺纹强度较差，一般宜设计为粗牙螺纹。 ②模塑螺纹的精度不高，一般低于GB3级。
3.5.3 模塑螺纹的结构设计
由模具的螺纹成型机构对应获得三种结构型式的模塑螺纹。它们是整圆型螺纹、对拼型螺纹和间断型螺纹。
3.5.3 模塑螺纹的结构设计
模塑螺纹起止端不能设计退刀槽，也不宜用过渡锥面结构。这一点与金属螺纹件的要求不同。模塑螺纹起止端应设计为圆台即圆柱结构，以提高该处螺纹强度并使得模具结构简单。
ab
c
3.5.4 塑料齿轮的设计
设计时应避免模塑、装配和使用塑料齿轮时产生内应力或应力集中；避免收缩不均而变形。为此，塑料轮要尽量避免截面突变，应以较大圆弧进行转角过渡，宜采用过渡配合和用非圆孔（见图3—40b）
对于细长型芯,为防止其弯曲变形，在不影响塑件的条件下，可在塑件的下方设支承柱来支撑。如图３-２５所示。
斜孔或形状复杂的孔可采用拼合的型芯来成型。如图３-２６所示
3.5 嵌件的安放与塑料螺纹、齿轮设计
3.5.1 塑料铰链设计 3.5.2 模塑螺纹的特点
3.5.3 模塑螺纹的结构 3.5.4 塑料齿轮的设计 3.5.5 带嵌件塑件的设计 3.5.6 嵌件的主要结构
a)(A-B)×100%/B≤5% b) (A-B)×100%/.4.1 脱模斜度设计 3.4.2 塑件壁厚设计 3.4.3 加强筋及其它增强结构 3.4.5 增加刚性减少变形的其他措施 3.4.6 塑件支承面的设计 3.4.7 塑件圆角的设计 3.4.8 塑件孔的设计 3.4.9 采用型芯拼合复杂型孔
a
b
图3-1具有侧孔的塑件

塑料模设计与制造指导手册

塑料模设计与制造指导手册〔内部讲义〕编著：李兆飞模具教研室广州铁路职业技术学院机械与电子工程学院模具教研室目录第一单元热塑料制品设计原那么 (4)一、尺寸、精度及表面粗糙度 (4)1、尺寸 (4)2、精度 (5)3、表面粗糙度 (6)二、形状 (6)三、脱模斜度 (7)四、壁厚 (8)五、加强筋 (9)六、支承面 (9)七、圆角 (10)八、孔〔槽〕 (10)九、螺纹 (11)十、嵌件 (13)十一、标记、符号、图案、文字 (15)第二单元塑料模设计原那么与查验 (17)一、塑料模具设计原那么 (17)1、模具设计上应与热交换器相似 (17)2、采纳平稳式流道系统 (18)3、模具设计标准化 (18)4、足够的排气装置 (18)5、确保快速修模，设计时预留修模量 (18)6、以容易组立，不易出错为原那么 (18)7、以模具易加工，精度适当为原那么 (18)二、模具设计要项查检 (19)〔一〕注塑模具设计之运算公式 (19)〔二〕注塑模具结构设计 (20)第三单元塑料模具设计流程 (23)一、方框图 (23)二、流程表 (24)第四单元塑胶模具制作规范 (28)一、确认图面 (28)二、模具制作流程 (29)三、试模前务必完成以下之确认 (29)第五单元注射模设计实例 (31)一、注射成型工艺规程的编制 (31)1、塑件的工艺性分析 (31)2、运算塑件的体积和重量 (32)3、塑件注射工艺参数的确定 (32)二、注射模的结构设计 (32)1、分型面选择 (33)2、确定型腔的排列方式 (33)3、浇注系统设计 (33)4、抽芯机构设计 (34)5、成型零件的结构设计 (34)三、模具设计的有关运算 (35)1、型腔和型芯工作尺寸运算 (35)2、型腔侧壁厚度和底板厚度运算 (36)四、模具加热与冷却系统的设计 (37)五、注射机有关参数的校核 (38)六、绘制模具总装图和非标零件工作图 (38)第六单元模具制造实例 (41)一、模具总体工艺流程图 (41)二、注射模要紧零件加工工艺规程的编制 (42)三、模具装配工艺流程编制 (43)四、模具试模、调试与验收 (45)1 试模的目的与要求 (45)2 塑料模具的试模与调整 (46)3、塑料注塑模具的验收 (54)«塑料模具设计»课程设计指导书 (56)第一章概论 (57)一、课程设计的目的 (57)二、课程设计的选题 (57)三、课程设计差不多要求 (57)四、设计前的预备工作 (57)五、设计步骤及本卷须知 (58)六、设计任务 (58)七、设计参考资料 (58)八、设计时刻及学时安排 (58)第二章注射模具的设计程序 (59)一、同意任务书 (59)二、收集整理资料 (59)三、注射成型制品的分析 (59)1、消化塑料制件图 (59)2、塑料成型工艺分析 (59)3、明确制品的生产批量 (59)4、运算制品的体积和重量 (60)四、选择成型设备 (60)五、拟定模具结构方案 (60)六、绘制模具装配图和零件图 (60)七、校核模具图样 (60)八、编写模具设计运算说明书 (60)第三章注射模具设计及模具图绘制 (61)第一节模具结构设计 (61)一、模具的差不多结构 (61)二、注射模具设计的差不多内容 (61)三、注射模具设计的有关运算 (62)四、模具零部件的设计 (62)第二节模具图的绘制与校核.............................................................................. 错误!未定义书签。

塑胶件结构设计手册(精华板)

1.0 选择材料的考虑因素任何一件工业产品在设计的早期过程中，一定牵涉考虑选择成形物料。

因为在产品生产时、装配时、和完成的时间，物料有着相互影响的关系。

除此之外,品质检定水平、市场销售情况和价格的厘定等也是需要考虑之列.所以这是无法使用概括全面的考虑因素而定出一种系统性处理方法来决定所选择的材料和生产过程是为最理想。

1。

1 不同材料的特性1。

ABS•用途：玩具、机壳、日常用品•特性：坚硬、不易碎、可涂胶水，但损坏时可能有利边出现设计上的应用:多数应用于玩具外壳或不用受力的零件。

2.PP•用途:玩具、日常用品、包装胶袋、瓶子•特性：有弹性、韧度强、延伸性大、但不可涂胶水。

•设计上的应用:多数应用于一些因要接受drop test（跌落测试）而拆件的地方.3.PVC•用途：软喉管、硬喉管、软板、硬板、电线、玩具•特性：柔软、坚韧而有弹性。

•设计上的应用:多数用于玩具figure（人物），或一些需要避震或吸震的地方。

4.POM•用途:机械零件、齿轮、摃杆、家电外壳•特性：耐磨、坚硬但脆弱,损坏时容易有利边出现（Fig. 1。

1。

6)。

•设计上的应用：多数用于胶齿轮、滑轮、一些需要传动，承受大扭力或应力的地方。

5。

Nylon (尼龙)•用途:齿轮、滑轮•特性：坚韧、吸水、但当水份完全挥发后会变得脆弱。

•设计上的应用：因为精准度比较难控制,所以大多用于一些模数较大的齿轮。

6。

Kraton （克拉通）用途: 摩打垫特性：柔软，有弹性,韧度高，延伸性强。

设计上的应用：多数作为摩打垫,吸收摩打震动，减低噪音。

Table 1.1.1 一般胶料的特性与用途2.0 壁厚 [Wall Thickness]壁厚的大小取决于产品需要承受的外力、是否作为其它零件的支撑、承接柱位的数量、伸出部份的多少以及选用的塑料材料而定。

一般的热塑性塑料的壁厚设计应以4mm为限.从经济角度来看,过厚的产品设计不但增加物料成本，延长生产周期（冷却时间),增加生产成本。

塑料制品设计师指南

塑料制品设计师指南基本资料塑料制品设计师指南作者：唐志玉出版社：出版年： 1993年09月第1版页数：定价： 21.1装帧：ISAN：内容简介本书包括聚合物结构特征与性能、填料对塑料性能的影响、蠕变与断裂、结构件设计等20章。

书目：举报失效目录超星目录第一章总论§1.1塑料特性与用途§1.2设计内容§1.3设计程序1.3.1设计思想1.3.2设计步骤第二章聚合物结构特征与性能§21 塑料的分类2.1.1接塑料的物理化学性能分2.1.2按塑料用途分2.1.3按塑料成型方法分2.1.4按塑料半成品和制品分§2.2高聚物的结构与性能2.2.1 高聚物分子运动特性2.2.2高聚物的力学状态和热转变2.2.3高聚物的玻璃化转变2.2.4聚合物的结晶2.2.5高聚物的取向2.2.6高聚物的静电效应参考文献第三章塑料的应力-应变行为§3.1模量、柔量与泊松比§3.2虎克弹簧与牛顿粘壶§3.3 Maxwell和Voigt模型3.3.1 Maxwell模型3.3.2 Maxwell模型在动态力场中的应用 3.3.3 Maxwell-Weichert模型3.3.4 Voigt模型3.3.5 Voigt模型在动态力场中的应用 3.3.6四元件组合模型3.3.7 Voigt-Kelvin模型§3.4应力-应变-时间的三维图§3.5 Bo1tzman叠加原理第四章填料对塑料性能的影响§4.1填料定义与分类§4.2填料品种及属性§4.3填料聚集状态及性能的影响 4.3.1 填料几何形状4.3.2填料粒度分布4.3.3填料的表面积4.3.4填料的堆砌系数4.3.5化学组成对性能的影响§4.4填料的表面处理§4.5填料的改性作用4.5.1模量和抗张强度4.5.2抗压强度4.5.3蠕变及其伸长4.5.4改善热性能4.5.5改进电性能§4.6填料的增强作用4.6.1玻璃纤维增强塑料4.6.2增强机理及纤维临界长度 4.6.3影响增强性的因素§4.7填料对塑料加工性能的影响 4.7.1粘度变化4.7.2流变行为的改变4.7.3填料的选择第五章蠕变与断裂§5.1蠕变行为5.1.1蠕变数据5.1.2温度对应变的影响 5.1.3其它应变形式5.1.4应变的回复5.1.5间歇应力下的蠕变§5.2断裂现象5.2.1脆性断裂5.2.2韧性断裂5.2.3温度的影响§5.3断裂与蠕变参考文献第六章结构件设计§6.1设计过程及特点6.1.1工作要求与失效形式 6.1.2 材料选择6.1.3计算过程§6.2构件设计实例6.2.1 柱体设计6.2.2 叶片轮设计6.2.3悬臂梁设计6.2.4圆管计算§6 3应变回复的计算第七章刚性设计§7.1 夹芯板7.1.1夹芯板的刚性分析7.1.2技术性能指标7.1.3材料选用7.1.4制造与固定7.1.5 设计实例§7.2波纹板7.2.1波纹板特征7.2.2屋顶设计§7.3塑料曲面结构参考文献第八章动态载荷分析§8.1交变载荷与疲劳强度 8.1.1 交变应力8.1.2疲劳试验8.1.3疲劳强度§8.2滞后热效应8.2.1滞后热现象8.2.2防止滞后热软化的方法 8.2.3滞后热平衡分析§8.3减振特性8.3.1塑料的阻尼特性8.3.2减振计算8.3.3阻尼对应力和疲劳的影响§8 4冲击载荷8.4.1 冲击强度8.4.2半波正弦脉冲载荷8.4.3抗冲保护计算参考文献第九章成型方法对塑件设计的影响§9.1常用的成型方法9.1.1熔体成型9.1.2固相成型§9.2模具的限制9.2.1避免侧孔、侧凹9.2.2脱模斜度9.2.3 分型线9.2.4 浇口痕9.2.5制品公差9.2.6壁厚9.2.7 筋与凸台9.2.8圆弧与倒角9.2.9表面处理9.2.10孔与嵌件§9.3成型方法的限制9.3.1挤出成型9.3.2 吹塑成型9.3.3反应注射成型9.3.4热成型9.3.5 浇注成型参考文献第十章成型过程对制品性能的影响§10.1型腔模中所出现的问题 10.1.1充模问题10.1.2缩孔与收缩应力10.1.3熔体流动受阻10.1.4各向异性10.1.5浇口区取向10.1.6熔接缝10.1.7碳化与焦斑10.1.8制品内应力10.1.9表面缺陷10.1.10收缩率波动§10.2挤出成型中所遇到的问题 10.2.1取向与内应力10.2.2记忆效应10.2.3截面变形10.2.4 尺寸变化§10.3热成型中存在的问题10.3.1取向与冻结应力10.3.2截面厚薄不均10.3.3解模塑趋向10.3.4双重削弱作用§10.4吹塑成型中的问题§10.5浇铸成型给制品带来的问题参考文献第十一章环境因素的危害§11.1塑料制品的老化现象§11.2热环境老化11.2.1 热裂解11.2.2热氧化§11.3光氧环境老化11.3.1光氧老化机理11.3.2防止光老化方法§11.4化学介质老化11.4.1耐腐蚀性与评定标准11.4.2不同塑料的耐腐蚀性能11.4.3防腐塑料选用特性§11.5其它老化形式与环境试验 11.5.1臭氧环境老化11.5.2水解老化11.5.3生物老化11.5.4电晕老化11.5.5环境应力开裂11.5.6低温脆裂11.5.7环境试验§11.6常用塑料光热老化特性11.6.1聚烯烃塑料11.6.2卤代烯烃塑料11.6.3 ABS塑料和丙烯酸酯类塑料 11.6.4聚醚塑料11.6.5聚酰胺塑料11.6.6聚酯、聚砜塑料11.6.7热固性塑料参考文献第十二章塑料制品设计过程§12.1设计准备12.1.1设计思想12.1.2调查研究12.1.3设想方案§12.2设计步骤12.2.1功能设计12.2.2材料选择12.2.3结构设计12.2.4尺寸设计12.2.5性能估算12.2.6模型、制样及绘图12.2.7试生产及定型§12.3设计师的责任12.3.1不断更新产品结构12.3.2质量与价格兼顾参考文献第十三章CAD与塑件设计§13.1 CAD概述13.1.1CAD的概念13.1.2 CAD系统的规模13.1.3 CAD技术的核心13.1.4 CAD系统的配置13.1.5 CAD的意义和作用§13.2 CAD在塑件设计中的应用 13.2.1塑件设计的一般过程13.2.2塑件设计目录的编制13.2.3塑件设计方法诸要素§13.3注塑流动的计算机模拟 13.3.1注塑流动模拟的基本原理 13.3.2注塑流动的有限元分析 13.3.3 Moldflow软件的使用参考文献第十四章联接件设计§14.1卡夹联接14.1.1联接原理与分类14.1.2设计实例§14.2铰链联接§14.3常用联接实例§14.4压力装配联接参考文献第十五章轴承和齿轮设计§15.1塑料的摩擦和磨损性能 15.1.1摩擦15.1.2磨损§15.2轴承设计15.2.1轴承材料15.2.2轴承类型15.2.3设计考虑15.2.4橡胶轴承§15.3齿轮设计15.3.1齿轮模塑成型15.3.2齿轮几何参数计算15.3.3齿轮失效形式15.3.4齿轮弯曲疲劳强度计算 15.3.5齿面接触疲劳强度计算 15.3.6材料选择参考文献第十六章电工塑件设计§16.1塑料的电学性能16.1.1塑料的绝缘性16.1.2塑料的导电性16.1.3塑料的高电压性能§16.2接插件设计16.2.1 概述16.2.2接插件的技术要求1 6.2.3接插件用塑料材料§16.3印刷线路板16.3.1工艺过程16.3.2技术要求§16.4线缆包覆层设计16.4.1概述16.4.2 电缆用塑料材料16.4.3电缆绝缘层计算16.4.4 电缆料使用要求参考文献第十七章光学塑件设计§17.1 塑料的光学性质17.1.1透光性和透明性17.1.2折射和反射17.1.3光弹性17.1.4持久性和稳定性§17.2光管效应及其应用§17.3透镜和菲涅尔透镜§17.4光学领域其它应用17.4.1 镜片制造17.4.2光栅复制17.4.3其它用途§17.5光学塑料材料参考文献第十八章泡沫塑料及其制品设计§18.1泡沫塑料分类18.1.1按泡孔结构分18.1.2按软硬程度分18.1.3按密度大小分§18.2泡沫塑料结构18.2.1 泡孔形状18.2.2泡孔尺寸18.2.3开孔系数18.2.4 泡沫密度§18.3泡沫塑料性能18.3.1力学性能18.3.2热学性能18.3.3尺寸稳定性18.3.4 电学性能18.3.5 漂浮性能18.3.6吸水性和透湿性18.3.7声学性能18.3.8缓冲减震性能18.3.9阻燃性能18.3.10化学性能18.3.11生物性能§18.4结构泡沫18.4.1结构泡沫的结构与特性 18.4.2结构泡沫成型方法18.4.3增强结构泡沫18.4.4组合泡沫§18.5耐高温泡沫18.5.1有机硅泡沫18.5.2聚异氰脲酸酯泡沫18.5.3聚苯并咪唑泡沫18.5.4聚酰亚胺泡沫§18.6泡沫塑料应用18.6.1包装用制品设计18.6.2绝热和建筑用制品设计18.6.3交通运输用制品设计18.6.4海运和海洋事业用制品18.6.5家具和日常生活用制品18.6.6医疗技术材料18.6.7军事和航空航天技术应用参考文献第十九章表面装饰与着色§19.1表面绘画技术19.1.1模塑花纹技术19.1.2热固性塑料制品的绘画技术 19.1.3热塑性塑料制品的绘画技术 19.1.4发泡装饰技术19.1.5其它花纹技术§19.2表面涂饰技术19.2.1涂饰的功能19.2.2涂料的种类19.2.3涂料的选用19.2.4涂饰预处理19.2.5涂饰工艺19.2.6涂饰对制品的设计要求§19.3表面金属化19.3.1金属喷镀19.3.2真空镀膜19.3.3化学镀金与电镀19.3.4电镀塑料制品的设计要求§19.4表面印刷技术19.4.1表面烫印19.4.2丝网印刷(绢印)19.4.3其它印刷技术§19.5塑料着色19.5.1着色剂简介19.5.2着色剂选择19.5.3塑料着色技术参考文献第二十章塑料性能与鉴别§20.1性能规范与标准20.1.1物理性能20.1.2热学性能20.1.3力学性能20.1.4 电学性能20.1.5化学性能20.1.6老化性能§20.2塑料鉴别20.2.1燃烧鉴别法20.2.2溶解性试验法20.2.3元素检定法20.2.4最后鉴定法20.2.5现代鉴定法§20.3聚合物分子结构 20.3.1聚烯烃树脂20.3.2 乙烯基树脂20.3.3丙烯酸树脂20.3.4聚酰胺树脂20.3.5聚醚树脂20.3.6含氟树脂30.3.7芳杂环树脂20.3.8纤维素塑料20.3.9聚醚酯树脂20.3.10其它热固性树脂参考文献1。