外文翻译----三维注射成型流动模拟的研究
立体光照成型的注塑模具工艺的综合模拟外文翻译
Integrated simulation of the injection molding process with stereolithography 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 But all current simulation packages for conventional injection molding are no longer applicable to this new type of injection molds, mainly because the property of the mold material changes greatly.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 ex perimental 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 inRP-fabricated stereolithography (SL) molds have a thermal conductivity that is less than one thousandth 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 fundamental understanding of how the modifica tions to 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 di stortion 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 simulation 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 createpolymer 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 functional 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 bound ary 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 photopolymer 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, thesurface 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 thesimulation resultIn 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 in the 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 itis 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 the surface 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 anArrhenius-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. Thesteady 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 expan sion coefficient and Poisson’s ratio of the material, and r = |y−x|. clk(x) is the surface coefficient 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 on the 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 stretching element 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 thecompleted 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”, “thre e-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 thermalconductivitiesFig. 7. Comparison of the distortion variation in the Z direction for different thermalconductivitiesFig. 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 increasespart 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。
外文翻译---一个注射模填充模拟的几何方法
本科毕业论文外文翻译外文译文题目（中文）：一个注射模填充模拟的几何方法学院: 机械自动化学院专业: 模具设计与制造学号:学生姓名:指导教师:日期: 2009.12International Journal of Machine Tools & Manufacture 45 (2005) 115–124A geometric approach for injection mould filling simulationC.K. Au*School of Mechanical and Production Engineering, Nanyang Technological University, 50Nanyang Ave, 639798 SingaporeReceived 15 March 2004; received in revised form 7 June 2004; accepted 15 June 2004国际期刊机床与制造45 (2005) 115-124一个注射模填充模拟的几何方法C.K. Au南洋理工大学机械生产工程学院，新加坡南阳路50号，639798 标准版本2004年3月15;修订版本2004年6月7;正常版本2004年6月15号摘要本文讨论一个关于研究起源于点源的流阵面在带障碍的有界腔内流动规律几何技巧方法。
该技术是基于这样的假设塑料零件壁厚与流速成正比。
复杂注塑模具的腔内的流动是由四种基本流型，即吸收，折射，衍射和合并。
结合这四个流动模式在注塑成型法迅速产成填充样式在塑料生产发展期方案设计阶段有益的。
虽然讨论的应用背景是塑料注射成型，但这个技术在许多领域也是适用的。
2004年爱思唯尔有限公司版权所有关键字：流阵面；模型填充模拟；注射成型法1.导论成型的制造过程依赖模具成型的塑料和聚合物或者急需的金属，液态层。
与行业一样重要的大部分工作的工具和模具在过去20年来很大程度上是发展的，这就是对具体的边界条件运用现成的仿真或优化。
模具设计外文翻译--注射／压缩流体组合模塑的数值模拟
附录二：外文翻译原件及翻译稿Numerical simulation of injection/compression liquid composite moldingPart 1. Mesh generationK.M. Pillai a, C.L. Tucker III, F.R a. Phelan Jr ba Department of Mechanical and Industrial Engineering, University of Illinois,1206 W. Green Street, Urbana, IL61801, USAb Polymer Composites Group, Polymers Division, Building 224, Room B108, National Institute ofStandards and Technology, Gaithersburg, MD20899, USAAccepted 14 June 1999───────────────────────────────────────AbstractThis paper presents a numerical simulation of injection/compression liquid composite molding, where the fiber preform is compressed to a desired degree after an initial charge of resin has been injected into the mold. Due to the possibility of an initial gap at the top of the preform and out-of-plane heterogeneity in the multi-layered fiber preform, a full three-dimensional (3D) flow simulation is essential. We propose an algorithm to generate a suitable 3D finite element mesh, starting from a two-dimensional shell mesh representing the geometry of the mold cavity. Since different layers of the preform have different compressibility, and since properties such as permeability are a strong function of the degree of compression, a simultaneous prediction of preform compression along with the resin flow is necessary for accurate mold filling simulation. The algorithm creates a coarser mechanical mesh to simulate compression of the preform, and a finer flow mesh to simulate the motion of the resin in the preform and gap. Lines connected to the top and bottom plates of the mold, called spines, are used as conduits for the nodes. A method to generate a surface parallel to a given surface, thereby maintaining the thickness of the intermediate space, is used to construct the layers of the preform in the mechanical mesh. The mechanical mesh is further subdivided along the spines to create the flow mesh. Examples of the three-dimensional meshes generated by the algorithm are presented. 1999 Elsevier Science Ltd. All rights reserved.Keywords: Liquid composite molding (LCM); E. Resin transfer molding (RTM)───────────────────────────────────────1. IntroductionLiquid composite molding (LCM) is emerging as an important technology to make net-shape parts of polymer-matrix composites. In any LCM process, a preform of reinforcing fibers is placed in a closed mold, then a liquid polymer resin is injected into the mold to infiltrate the preform. When the mold is full, the polymer is cured by a crosslinking reaction to become a rigid solid. Then the mold is opened to remove the part. LCM processes offer a way to produce high-performance composite parts using a rapid process with low labor requirement.This paper deals with a particular type of LCM process called injection/compression liquid composite molding (I/C-LCM). In I/C-LCM, unlike other types of LCM processes, the mold is only partially closed when resin injection begins. This increases the cross-sectional area availablefor the resin flow, and decreases flow resistance by providing high porosity in the reinforcement. Often, the presence of a gap at the top of the preform further facilitates the flow. After all of the resin has been injected, the mold is slowly closed to its final height, causing additional resin flow and saturating all portions of the preform. The I/CLCM process fills the mold more rapidly, and at a lower pressure than the other LCM processes that use injection alone.Complete filling of the mold with adequate wetting of the fibers is the primary objective of any LCM mold designer; incomplete filling in the mold leads to production of defective parts with dry spots. There are many factors which affect the filling of the mold: permeability of the preform, presence of gaps in the mold to facilitate resin flow, arrangement of inlet and outlet gates, injection rates of resin from different inlet ports, etc. Often it is not possible for the mold designer to visualize and design an adequate system for resin infusion by intuition alone, and mold filling simulations are used to optimize mold performance. The situation in I/C-LCM is more complex than ordinary LCM because of compression of the mold during the filling operation. As a result, numerical simulation of the mold filling process in I/C-LCM becomes all the more important.I/C-LCM fiber preforms frequently comprise layers of different reinforcing materials such as biaxial woven fabrics, stitch-bonded uniaxial fibers, random fibers. Each type of material has a unique behavior as it is compressed in the mold. When such different materials are layered to form the preform, each of them will compress by different amounts as the mold is closed. This behavior is illustrated in Fig. 1, which shows a small piece of a mold. Here the lighter center layer deforms much more than the darker outer layer as the mold is closed.(B) After compression (A) Before compressionFig. 1. Uneven deformation of preform layers under compression.Capturing this deformation behavior during compression is critical to the accuracy of any I/C-LCM process model. Resin flows through the preform at all stages of compression, and the porosity and permeability of the preform are critical in determining the resin flow. The ratio of deformed volume to initial volume determines the porosity of each preform layer, and from this one can determine the layer's permeability, either from a theoretical prediction or a correlation of experimental data. Because of this strong coupling between the state of compression in a preform layer and its permeability, computations for fluid flow and preform compression have to be done simultaneously for mold filling simulations in I/C-LCM.Significant steps have already been taken to computationally model the mold filling in the I/C-LCM process. A computer program called crimson, is capable of isothermal mold fillingsimulation which involves simultaneous fluid flow and preform compression computations in the flow domain. But the initial capacity of crimson is limited to two-dimensional (2D) planar geometries where prediction of preform compression is straightforward. Deformation of the preform is modeled using the incremental linearized theory of elasticity; the mathematics simplifies due to reduction in the number of degrees of freedom (DOF) associated with displacement from the usual three to one along the thickness direction. However parts made by the I/C-LCM process typically have complicated three-dimensional shapes and this reduction of the mathematical complexity is no longer possible. The present paper describes our effort to expand the capability of crimson by enabling it to tackle any arbitrary non-planar three dimensional (3D) mold geometry.Most injection molding simulation programs read for the mold geometry in the form of a shell mesh. Even if it were possible to transmit the full geometrical information about the mold through a 3D mesh, it still is difficult to incorporate all the information of relevance to the process engineer. The latter needs to know the thicknesses of various layers of fiber mats and their corresponding porosities at each time step. As a result, it is very important that elements representing different layers of preform in the 3D finite element mesh fall within separate layered regions. Overlap of an element onto more than one region is not acceptable as the element has to carry the material properties, such as porosity, permeability, of only one fiber mat. Mesh-generators in state-of-the-art commercial software such as PATRAN are not designed to generate such a 3D mesh. Consequently, we decided to create a preprocessor suitable for I/C-LCM mold filling simulation.The objectives of this paper are to introduce basic ideas about modeling mold filling in 3D I/C-LCM parts, and to introduce an algorithm to generate a 3D finite element mesh from a given 2D shell mesh for preform and flow computations. In subsequent papers, we will model finite deformation of preform using the non-linear theory of elasticity, and use this information to model resin flow in an I/C-LCM mold.2. Generating a 3D mesh from the given 2D shell meshOur aim is to develop a preprocessor that can generate 3D finite element meshes for flow computations starting from a 2D shell mesh. We wish to allow the I/C-LCM process engineer to include all relevant information such as thicknesses of the layers of the preform, thickness of the gap, into the mesh.A - open gap everywhere C - just touching / partly compressedD - fully compressed everywhere B - open gap / just touchingFig. 2. A schematic describing the various stages of the compression/injection molding process. The top plate of the mold moves along theclamping vector, while the bottom plate is stationary. Stages A–C arethree possible starting positions of the top plate. Stage D shows the finalconfiguration of the mold when it is fully compressed.Fig.2 describes the three possible starting mold configurations (A-C) for a typical angular part geometry. Case A represents the starting configuration for the open mold injection/compression (I/C) molding, with ample gap between the top plate and preform. Cases B and C occur when the gap is partly or completely eliminated before the start of the injection process. In the former, the preform is completely uncompressed with gaps at a few places. In the latter, the gap is removed at the cost of partial compression of the preform in certain regions. In the present paper, mesh generation for configuration A only will be addressed. Once this mesh is created, cases B and C can be generated by solving for the mechanical compression of the preform.As we shall see in the subsequent papers, six-noded wedge elements and eight-noded brick elements are adequate for modeling both the resin flow and preform compression. Our mesh generation algorithm is designed to generate such elements from the three- and four-noded triangular and quadrilateral elements of the shell mesh.2.1. Mechanical and flow meshesDevelopment of the 3D mesh for flow computations from a given 2D shell mesh, representing the part geometry, is divided into two stages. In the first stage, an intermediate mechanical mesh is created, where the number of layers of elements equals the number of fiber mats in the lay-up, with the thickness of the mats equal to the height of those elements. Such a coarse mesh is adequate to track deformation of the mats during compression of the mold. In the second stage, the mechanical mesh is further subdivided along the thickness direction to create a more refined mesh, called the flow mesh, which is used for flow calculations.3. Basic concepts of mesh generation algorithmWe first introduce two basic ideas that form the backbone of our mesh generation algorithm: spines and parallel surfaces.3.1. Use of spinesOne of the salient features of our mesh generation technique is the use of spines to track the nodes of the 3D mechanical mesh. This is similar to the use of spines in the free boundary problems where they have been used to adapt the computational mesh with time. These spines are lines connecting node points of the top mold surface to their counterparts of the bottom mold surface.4. AlgorithmThe main actions carried out in our mesh generation algorithm are as follows:1. Read data describing the 2D shell mesh. The mesh data is read, along with the information important for process modeling such as direction of clamping, properties of fiber mats, initial gap provided at the top of the preform.2. Construct the upper surface of the final part. The upper surface is generated parallel to the input 2D shell mesh which represents the bottom, immovable surface of the mold. The inputthicknesses between the given and upper surfaces are taken to be the final thickness of the I/C-LCM mold (equal to the desired part thickness).5. Examples and discussionA computer program has been developed to implement the mesh generation algorithm, and tested for its efficacy and robustness. In the following sections, examples of the creation of 3D computational meshes from 2D shell meshes are presented. Since the thicknesses in the I/C-LCM parts are much smaller than their other dimensions, realistic meshes are relatively thin. To highlight important features of the algorithm, the thicknesses of the meshes are scaled up in the following examples. In each example, a gap that is a certain fraction of the total thickness of the uncompressed preform is provided between the upper surface of the preform and the top mold plate.6. Summary and conclusionsIn this paper, we present a methodology to create 3D finite element meshes for modeling mold filling in I/CLCM. We propose the concept of predicting preform compression using the coarse mechanical mesh, and predicting fluid flow using the finer flow mesh. A mesh-generating algorithm, to create the mechanical and flow meshes from a given shell mesh, is presented. This algorithm incorporates information about the position of fiber mat interfaces in a multi-layered preform, which is crucial for accurate modeling of the filling process. A technique to create surfaces parallel to any arbitrary shell mesh surface enables us to represent the interfaces accurately. Further, the use of spines in mesh generation reduces the number of unknowns at each node from three to one. The algorithm is used successfully to create the mechanical and flow meshes from two different shell meshes; its robustness is demonstrated by creating a 3D mesh from a shell mesh for an arbitrary mold shape. The need to refine the shell mesh in the region of a step change in the thickness of the mold is the main limitation of the algorithm. In subsequent papers, we will use the mechanical and flow meshes to simulate preform compression and resin flow during mold filling in I/C-LCM.注射／压缩流体组合模塑的数值模拟第一部分网格生成K.M. Pillai a, C.L. Tucker III, F.R a. Phelan Jr ba伊利诺斯大学机械工业工程系1206 W. Green Street, Urbana, IL61801, USAb国家标准与技术研究所，聚合物部，聚合物合成组Building 224, Room B108,Gaithersburg, MD 20899,USA收稿日期：1999年6月14日───────────────────────────────────────摘要文章介绍了注入模型中的树脂在一次初填充后其纤维预型件被压缩到所需的程度时，注射／压缩流体组合模塑的一种数值模拟。
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。
外文翻译---通过微注射成型复制聚合物微小结构的实验和分析
本科生毕业设计 (论文)外文翻译原文标题Implementation and analysis of polymericMicrostrcucture replication by microInjection molding译文标题通过微注射成型复制聚合物微小结构的实验和分析作者所在系别作者所在专业作者所在班级作者姓名作者学号指导教师姓名指导教师职称完成时间2011 年10 月译文标题通过微注射成型复制聚合物微小结构的实验和分析原文标题Implementation and analysis of polymeric microstructure replication by micro injection molding作者Yu-chuan su,Jatan Shah,Liwei Lin译名苏豫川，Jatan Shah,林利伟国籍美国原文出处2004 IOP Publishing Ltd Printed in th UK通过微注射成型复制聚合物微小结构的实验和分析苏豫川，Jatan Shah,林利伟1.伯克利传感器&执行器中心，美国加州大学，伯克利，CA 94720，美国2.机械工程学系，美国加州大学，伯克利，CA 94720，美国3.机械工程学系，密歇根大学，Ann Arbor，MI 48105, 美国邮箱: yuchsu@收到90 2003年9月2003年12月17日发布在线在/JMM/14/415（作者：10.1088/0960-1317/14/3/015）摘要本文介绍了传统的注塑成型工艺适应大规模复制聚合物微小结构与相应的模具设计和控制过程。
使用湿蚀刻硅片作为模具镶件的表面微小结构，我们已经成功地预测，改善和优化复制的结果。
聚合物熔体在微型模具型腔中的流动特点是试验和仿真。
在各工艺参数中，温度被认为是关键因素，直接决定了注塑微小结构的质量。
根据收集到的实验和仿真结果，优化过程是为潜在的应用进行提高复制质量和建立指导方针。
模具制造专业外文翻译--注射成型应用
外文原文Injection Molding ApplicationsIntroductionThe use of plastic tooling in injection molding occurs within the field of Rapid Tooling (RT), which provides processes that are capable of producing injection mold tooling for low volume manufacturing at reduced costs and lead times. Such tooling allows the injection molding of parts in the end-use materials for functional prototype evaluation, short series production, and the validation of designs prior to hard tooling commitment. The term Rapid Tooling is somewhat ambiguous – its name suggests a tooling method that is simply produced quickly. However, the term is generically associated with a tooling method that in some form involves rapid prototyping technologies.Investigation and application of Stereo lithography (SL) to produce mold cavities for plastic injection molding primarily began in the 1990s. Initially the process was promoted as a quick route to soft tooling for injection molding (a tool to produce a relative low number of parts). The advantages of this have been somewhat diluted as other mold production technologies, such as high speed machining, have progressed,but other unique capabilities of the process have also been demonstrated.Stereo lithography has several process capabilities that are particularly advantageous for injection mold tooling, but we should also appreciate that is accompanied by some significant restrictions. This chapter introduces several aspects of the process accompanied by a discussion of its pros and cons, along with examples of work by different parties (Fig. 1).Fig. 1 Injection molding insert generated by stereo lithography, shown with part1. Mold ProductionIn order to discuss the main topic; the direct production of mold cavities, it is first necessary to differentiate this from the indirect route. This is not a significant topic since SL merely provides the master pattern which, irrespective of the process used to produce this, has little influence on the subsequent injection molding.1.1 Indirect Mold ProductionThe indirect methods involve the use of an initial geometry that has been produced by SL. This geometry is utilized as a pattern in a sequence of process steps that translate into a tool which may be made of a material different to that of the pattern.Cast epoxy tooling represents a common indirect plastic RT method for injection molding. The process begins with a 3D model (i.e. CAD) of the part to be molded.Subsequently this model is produced by SL to provide a master pattern around which the mold will be formed. Traditionally, the part is produced solely without provision for parting lines, gating, etc. Such ancillaries are generated by manual methods (i.e. by fixing additional features to the part). However, the advent of easier CAD manipulation allows the model to be produced including such features.Once the complete master pattern has been produced, the mold halves are created by casting epoxy around the pattern, thus recreating a negative profile of the pattern.The epoxy may include fillers in attempts to improve strength and thermal properties of the mold. Such fillers include metal and ceramic particles in various forms.1.2 Direct Mold ProductionThe direct methods involve a SL system directly generating the tooling cavityinserts in its native material. The accuracy of the SL RP process results in insertsthat require few further operations prior to their use in injection molding. Like allRP related techniques the process is dependent on a 3D CAD model of the intended geometry. Unlike indirect techniques, the whole tool insert is generated by SL and so a 3D CAD representation of the whole tool insert is required. This involves creating negatives of the part to form the mold insert bodies, plus the provisions for gating, part ejection, etc. Previously, this extra CAD work would have represented more work required in the preparation. Such input is now minimized as modern CAD manipulation packages (e.g. Materialise’s Magics software) allow the automation of such activities. Once generated, the cavity inserts need to be secured in a bolster to withstand clamping forces and to provide alignment to the mold halves.It should also be mentioned that direct SL tooling for injection molding has also been referred to as Direct AIM. This term was given to the process by 3D Systems(SL system manufacturers) and refers to Direct ACES Injection Molding. (ACES stands for “Accurate Clear Epoxy Solid,” which is a SL build style).2. The Requirement of the ProcessThe introduction of rapid prototyping has allowed engineers and designers togenerate physical models of parts very early in the design and developmentphase. However, the requirements of such prototypes have now progressed beyond the validation of geometry and onto the physical testing and proving of the parts.For such tests to be conducted, the part must be produced in the material and manner (process) that the production intent part will be. For injection molding, this situation highlights the requirement of a rapid mold-making system that can deliver these parts within time and cost boundaries.Stereo lithography provides a possible solution to this by providing the rapid creation of a mold. A negative of the part required plus gating and ejection arrangements are generated in 3D CAD to create a tool that is fabricated by SL.This provides an epoxy mold from which it is possible to produce plastic parts by injection molding.Both Luck et al. and Roberts and Ilston evaluated SL in comparison with other direct RP mold-generating techniques for producing a typical development quantity of moldings. The SLmolding process was found to be a superior alternative for producing design-intent prototypes.It has also been noted that other alternative techniques involve additional steps to the process, therefore becoming less direct and not really RT. Other advantages of the process have been highlighted beyond the prototype validation phase. Since the tool design has been verified, the lead-time and cost involved in the manufacture of production tooling is also often reduced as the tool design has already beenproven.During the early years of SL it was never envisaged that such a RT method would be possible. At first glance the application of SL for injection mold tooling seems unfeasible due to the low thermal conductivity and limited mechanical properties of epoxy, especially at high temperatures. The glass transition temperature of SL materials available was only ~60_C, while the typical temperature of an injected polymer is over 200_C. Despite these supposed limits, successful results were achieved by SL users worldwide, including the Danish Technological Institute, Ciba Geigy, Fraunhofer Institute, the Queensland Manufacturing Institute, and Xerox Corporation.3. Mold Design ConsiderationsIn terms of the mold’s actual cavity design, relatively little information exists on the specific requirements of SL tooling. The early white paper issued by 3DSystems suggests the incorporation of a generous draft angle, but does not statethe amount and recommends the use of a silicone based release agent (every shot) in an attempt to prevent the parts sticking to the inserts. Work has been conducted that quantifies the effects of draft angle on the force exerted on SL tools upon ejection of a molding. It has been shown that an increase in tooling draft angle results in a lower force required to remove a part from the tool. However, the effect of draft angle variation on ejection force is minimal and little compensation for the deviation from intended part geometry caused by the addition or removal of material required to form the draft.Work has been conducted to establish the cause of core damage during molding.This found that damage was not related to pressure, but to the size of the core features. Smaller core features were broken due to a shearing action caused by polymer melt movement.Experimentation has revealed two modes of wear during the material flow within the cavity. These modes were abrasive at medium flow points (i.e. sharp corners),and ablative at highflow points (i.e. injection points). Other work has also emphasized the importance of the material flow influenced by mold design, identifying gating, and parting line shut off areas as points of potentially high wear.Fig. 2 Parts requiring different gating arrangements according to molding material4. injectionlaser system’s degree of curing is dependent upon the pulse frequency and the hatch spacing. Generally a continuous mode laser system allows for greater energy exposure.With respect to post-curing operations it should be noted that the amount of curing is not greatly affected by UV environment exposure. If thermal post curing is tobe used it should also be noted that a large majority of warpage occurs during this stage, which may be a concern if thin walled sections are in existence.The layer thickness of each build slice dictates the SL part’s roughness on surfaces parallel to the build direction. When this surface roughness is parallel to a mo lded part’s direction of ejection it has a resultant effect on the force required to remove the part from the mold which in turn applies a force to the insert which could result in damage. This surface roughness and the ejection forces experienced,correspond linearly to the build layer thickness. The solution is to re-orientate the SL build direction or employ a lesser layer thickness.4.1 Injection MoldingDuring molding, a release agent should be frequently used to lower the force experienced by the too l due to part ejection. In the author’s experience, a siliconelike agent is the most successful. Low-injection pressures and speeds should be used whenever feasible. Much lower settings are feasible in comparison to some forms of metal tooling due to SL heat transfer characteristics as discussed within this section.Early recommendations for SL injection molding stated that since damage occurs during part ejection it was appropriate to allow as much cooling prior to mold opening as possible. This reduced the tendency of the parts to stick to the inserts . The author has trialled this approach, which often leads to greater success, but the part-to-part cycle times are extremely long.More recent work has demonstrated that it is advantageous to eject the part as soon as possible (when part strength allows) before the bulk mass of cavity features have exceeded their glass transition point, when their physical strength is greatly reduced. This greatly reduces the heat transmitted into the tool and the cycle time for each part. Subsequently, it is also critical to monitor the mold temperature throughout the molding cycle to avoid exceeding the glass transition temperature (Tg) of epoxy, where tool strength is reduced. This entails each molding cycle beginning with the epoxy insert at ambient temperature and the part being ejected prior to Tg of the majority of the inserts volume being reached. This has been achieved in practice by inserting thermocouples from the rear of the cavity insert into the most vulnerable mold features such that the probe lies shortly beneath the cavity surface. Allowing the polymer to remain for sufficient time within the mold, while also avoiding critical Tg, is possible due to the very low thermal conductivity of SL materials.In addition, the low thermal conductivity of SL materials has been demonstrated to be advantageous in this application for injection mold tooling. It has been shown that the low thermal conductivity of SL tooling allows the use of low injection speeds and temperatures which are required due to the limited mechanical properties of SL materials. Traditional metal tooling needs these high pressures and speeds to prevent the injected polymer freezing prior to the mold completely filling.This is due to the rapid cooling of the injection melt when it comes into contact with the high thermal conductivity mold surface. Also, the SL tooling process has shown itself to be capable of producing parts that would not be possible under the same conditions using a metalmold. The thermal characteristics of SL tooling have made it possible to completely mold crystalline polyether ether ketone (PEEK), which has an injection temperature of 400_C (752_F).An equivalent steel mold would require a premolding temperature of about 200_C(392_F). An impeller geometry was successfully molded with vastly lower injection speeds and pressures were utilized, as shown in the Table 1 and Fig. 3.Table 10.1 Polyether ether ketone molding variables in SL mold vs. steel moldFig. 3 PEEK impeller molded by stereo lithography toolsA particularly illustrative account of the cooling conditions is shown in the above image. It can be seen that the polymer is primarily gray in color where it contacts SL surfaces indicating crystalline formation. Whereas where it comes into contact with the steel ejector pins it is brown, indicating localized amorphous areas. This is due to the difference in heat transfer of the two materials and hence the cooling rate experienced by the contacting polymer.5. Process ConsiderationsVarious polymers have been successfully molded by SL injection molding. These include polyester, polypropylene (PP), polystyrene (PS), polyamide (PA), polycarbonate,PEEK, acrylonitrile styrene acrylate, and acrylonitrile butadiene styrene.The greatest material limitation encountered has been the use of glass filled materials. All evidence indicates that the SL molding technique does not cope well with glass filled materials due to severe problems of abrasion to the SL cavity surface. This leads to poor quality, inaccurate parts, and undercuts in the cavity, which eventually result in the destruction of the SL insert. This abrasive nature has been quantified with a comparative SL molding study of PA 66 and PA 66 with 30% glass fiber content. The PA 66 enabled 19 shots prior to damage, while the glass filled variant allowed only 6 shots before the same level of damage was incurred . These findings are supported by work conducted by the author, with PA 66 with a 30% glass fiber content inducing high mold wear. However, it has been demonstrated that appropriate choices in mold design and process variables reduced the rate of wear. The use of appropriate settings has allowed the successful molding of a low number of partsas large as 165 _ 400 _ 48 mm (6.5 _ 16 _ 2 in.) with high geometrical complexity in PA66 with 30% glass content. The tool and parts are shown in Figs. 4 and 5.6 .Molded Part PropertiesDuring the course of my work with SL tooling, I have endeavored to investigate and pursue the most important aspect of tooling and molding; it is a means to an end.The end is the molded parts themselves. These are the products and if they are unsuitable, then tool performance is entirely irrelevant. Early work examining the resultant parts produced by the SL injection process described them only as being of a poor quality, effected by warping, and requiring a longer time to solidify due to the mold’s poor heat transfer producing a nonuniform temperature distribution. Other work also noted that using diffe ring materials in a mold’s construction (i.e. a steel core and a SL cavity) led to warping of the part due to the different thermal conductivities of the mold materials .Fig. 4 Large stereolithography molding toolFig. 5 Subsequent parts produced in polyamide 66 (30% glass fiber) The low thermal conductivity, and hence the low cooling rate, of the mold has a significant influence on the material properties of the molded parts. It was shown that parts from an epoxy mold exhibit a higher strength, but a lower elongation;around 20% in both cases .The differing mechanical properties of parts produced from SL molds as compared to thosefrom metal tools is also demonstrated in other work . This showed that the parts manufactured by SL molding had a lesser value of Young’s Modulus compared to those produced in a steel mold but possessed a greater maximum tensile strength and percentage elongation at break. These different part properties were attributed to a slow rate of heat transfer of the tool. This slow rate of heat transfer produces longer part cooling times giving a greater strength but less toughness.Research performed at Georgia Institute of Technology further investigated the mechanical properties of parts produced by the SL molding process. This work showed that noncrystalline and crystalline thermoplastic parts produced by the SL molding technique displayed differing mechanical characteristics than parts from traditional molds. Noncrystalline material parts possessed similar all-round mechanical properties compared to those produced in identical steel molds. However, crystalline thermoplastic parts demonstrated higher tensile strength, higher flexural strength, and lower impact properties compared to those manufactured in identical steel molds. More so with crystalline polymers than with amorphous materials, the mechanical properties of the plastic parts are influenced by the cooling conditions. These differing effects on mechanical properties have been demonstrated with PS (amorphous) and PP (crystal line). When the respective part’s mechanical properties were compared when produced by steel and by SL molds, the PS parts showed very little change while the PP parts demonstrated a great difference . In addition to differences in mechanical properties it has also been identified that some polymers exhibit different shrinkage according to the cooling conditions of the part during molding. These works indicate that crystalline polymers are susceptible to greater shrinkage when subjected to a slow cooling time.These differences in part properties have been attributed to the degree of crystallinity developed in the molded parts. This has been demonstrated by microscopic comparisons of parts produced by SL and metal alloy tooling. This revealed the spherulites (a crystal structure consisting of a round mass of radiating crystals) to be considerably larger from the SL tooling parts due to the higher temperatures and slower cooling involved during molding.In the wider field of general injection molding and plastics research, work has been conducted to identify and assess the variables that influence parts properties. These papers report a common theme, they identify the thermal history of the part to be a critical variable responsible for the parts resulting attributes. Recent work has shown that the slower molded part cooling imposed by SL tooling provides an opportunity to make some variations in the molding parameters for crystallinepolymers which allow the control of critical morphological factors (level of crystallinity). The subsequent level of crystallinity dictates many of the resultant part properties. The process modifications in this work were realized without changes to the machine, tool, or molded material (i.e. external cooling control, different polym er etc). This demonstrates a possible “tailoring” of molded part properties that would allow certain desirable part properties to be altered.These revelations demonstrate an advantage of SL tooling that was shown to not be possible in metal tooling. In summary, we must consider that the thermal characteristics of SL molds have an influence on the morphological structure of some parts. This may lead to a difference in the morphology of parts from SL tools as compared to those from metal tools. Such morphological differences can affect the shrinkage and mechanical properties of the molded part. When using SL tooling, one must decide if these differences are critical to the functionality of the part.7. ConclusionIn conclusion, SL molding is a viable process for some, but by no means all,injection molding tooling applications. Most important, is that the user should beinformed of the alternate design and processing requirements compared to conventional tooling, and be aware of the difference in resultant part characteristics, thus enabling realistic expectations and a more assured project outcome.注射成型应用摘要在快速成型领域中塑料模具在注塑成型时的应用，它在生产过程中可以制造出小批量生产降低成本和缩短时间的注塑模具。
外文翻译--注射成型机液压系统
外文翻译--注射成型机液压系统Injection molding machine hydraulic systemInjection molding machineInjection molding machine The injection molding machine is a kind of plastic machinery referred to as theinjection molding machine or injection molding machine thermoplastic or thermosetting material the use of plastic mold into various shapes of plastics molding equipment. Injection molding by the injection molding machine and mold.The plastic casts shaper is one kind of heating up the plastic the plasticizing, pours into with the aid of the advancement organization the melting plastic in the mold cavity, after cooling, the stereotypia forms the product the plastic to take shape the processing equipment. It can dispose the different mold, but time takes shape the contour complex product, is in the plastic machinery one of main aircraft types. The plastic injection takes shape already has very many forms. The hydraulic pressure type plastic injection shaper is one of them, it mainly has gathers the mold organization, injects the part, the hydraulic transmission and the plastic casts shaper is one kind of heating up the plastic the plasticizing, pours into with the aid of the advancement organization the melting plastic in the mold cavity, after cooling, the stereotypia forms the product the plastic to take shape the processing equipment. It can dispose thedifferent mold, but time takes shape the contour complex product, is in the plastic machinery one of main aircraft types. The plastic injection takes shape already has very many forms. The hydraulic pressure type plastic injection shaper is one of them, it mainly has gathers the mold organization, injects the part, the hydraulic transmission and the electricity control system and so on several parts of compositions, but the hydraulic pump, the hydraulic cylinder, each kind of hydraulic valve, the electrical machinery, the electrical part as well as the control measuring appliance are indispensable control part.Three major components of(1) clamping components. It is a molded member installation Die. Mainly by fixed templates, dynamic templates clamping mechanism, clamping hydraulic cylinder, ejector device.(2) injection member. It is a plastics injection molding machine member. Mainly by the feeding device and barrel, screw, nozzle, top plastic device, the injection of hydraulic cylinders, injection seat and its mobile hydraulic cylinders and other components.(3) hydraulic transmission and electrical control systems installed in the fuselage on the inside and outside the chamber, is the driving force of the injection molding machine and manipulating the control unit.Mainly composed of hydraulic pumps, hydraulic valves, motors, electrical components, and control instruments.SZ-250A type plastic injection molding machine are small injection molding machine. Each maximum injection capacity of 250 g. Basis for theplastic injection molding process, injection molding machine hydraulic drive system should meet the following requirements:(1) the mold clamping hydraulic cylinder having a sufficiently large clamping force, and its operating speed can be based on the requirements of the the clamping and Kai mold process varies.In the injection process, the molten plastic is often injected into the cavity to a high voltage of 4 ~ 15 MPa. Thus, the requirements of the mold clamping mechanism having a sufficiently large clamping force, and to ensure that the movable platen and the stationary platen closely bonded. Otherwise, the mold away from the seam will produce the the overflow edges phenomenon of plastic products. To this end, without making the size of the mold clamping hydraulic cylinder is too large, and the pressure is too high, often using the mechanical linkage force increasing mechanism to achieve the clamping and clamping.In order to shorten the time of air travel, improve productivity, clamping hydraulic cylinder should be fast-moving action template. However, in order to prevent damage to the mold and products, avoidmachine subject to strong vibration and impact-generated noise, but also consider the buffer of mold opening and closing process. Accordingly, the hydraulic cylinder in the mold opening and closing process, the speed of each stage is not the same. Usually slow—fast—slow process of change faster, and fast slow changes.(2) injection seat overall movement (forward or backward). Forwardwith sufficient thrust to ensure that the nozzle is brought into close contact with the mold gate. Further, it should be able to feed at a fixed feed, before feeding, and after three different preform its action to be adjusted.(3) the pressure and velocity of injection should be capable of adjustment, in order to meet the raw material, different the article geometry and layout of the mold gate and so the size of the injection force requirements, as well as the requirements of the different products on the injection speed.(4) melt into the cavity after the pressure keeping the cooling, when the cooling and solidification, should be able to cavity supplemental condensing shrinkage desired melt.In order to shorten the time of air travel, improve productivity, clamping hydraulic cylinder should be fast-moving action template. However, in order to prevent damage to the mold and products, avoidmachine subject to strong vibration and impact-generated noise, but also consider the buffer of mold opening and closing process. Accordingly, the hydraulic cylinder in the mold opening and closing process, the speed of each stage is not the same. Usually slow—fast—slow process of change faster, and fast slow changes.(5) the pre-molding process can be adjusted. Solidification stage cooling of the melt in the cavity, the plastic particles within the hopper by rotary screw barrel embroiled barrel, and goes on to the nozzle direction continuously. While heating plasticizing, stirring and extruded into the melt. Typically, called the weight of the barrel hourly plasticizing plasticizing capacity, as indicators of the production capacity of the injection molding machine. Premise barrel size to determine the the plasticizing capacity with screw speed. Accordingly, as the plastic melting point, fluidity, and the different products, the screw speed should be adjustable in order to adjust the plasticizing capacity.(6) the top of the cylinder speed is adjustable. Products during the cooling after molding, demolding the ejector, in order to prevent product damage, requiring top of the smooth motion, and the speed of the top of the cylinder should be able, depending on the product shape which can be adjusted.Working PrincipleThe working principle of injection molding machine and injection syringe, it is with the thrust of the screw (or plunger), the plasticizing good molten state (ie, viscous flow state), the plastic injected into the mold cavity closed good After curing stereotypes made the process of the products. Injection molding is a cyclical process, with each cycle including: dosing - molten plastics - to put pressure injection - filling Cooling - Kai-mode pickup. Remove the plastic parts and then re-closed mode, the next cycle. Injection molding machine operating items: injection molding machine operating projects including the control keyboard operation, the operation of electrical control system and hydraulic systems operating in three aspects. Separate action of the injection process, feeding action, injection pressure, injection speed, the top choice of the type, barrel temperature of each monitor, injection pressure and back pressure regulation. Screw injection molding machine molding process: First, granular or powdered plastic in the machine barrel, through which the screw rotates and the outer wall of the barrel, heating the plastic to become molten state, then the machine before clamping and injection shift, so that the nozzle closely aligns the mold gate Road, then the oil pressure to the injection cylinder Walter, screw forward to high pressure and a faster speed will melt into the closed mold temperature is low , after a certain period of time and pressure to keep(also known as pressure), cooling, curing, the mold can be opened to remove the products (the purpose of holding pressure to prevent the reflux of the melt in the mold cavity, supplementary material to the mold cavity, and to ensure that products have a certain density and dimensional tolerances). The basic requirements of the injection molded plastics, injection and molding. The plasticizing premise to achieve and guarantee the quality of the molded part, to meet the requirements of forming, injection must ensure there is enough pressure and speed.The same time, due to the high injection pressure, the corresponding cavity to produce a high pressure (average pressure of the cavity is generally between 20 ~ 45MPa), so there must be large enough clamping force. Thus, the injection unit and clamping devices are key components of the injection molding machine. Mainly in three aspects of the evaluation of plastic products, and the first appearance of quality, integrity, color, luster; the second is between the size and relative position accuracy; the third is to use the corresponding physical properties, chemical properties,electrical properties. These quality requirements are also different according to the different products using the occasion to require the scale. Defects of products is that the mold design, manufacturing precision and wear. In fact, the technical staff of the plastic processing plants often suffer from the face of technology means to compensate for the problems brought about by the mold defects but not the effectivenessof a difficult situation. Regulation of technology in the production process is the essential way to improve product quality and yield. Injection cycle is very short, if the process conditions are handled badly, the waste will be an endless supply. Adjustment process when the best time to change a condition to observe a few times, pressure, temperature, time, all with the tone, it could easily lead to confusion and misunderstanding, a problem do not know what reason. Measures to adjust the process, means, in many ways. Example: solving products Note dissatisfaction there is more than a dozen possible solutions to choose to address the crux of the problem, two major programs, in order to really solve the problem. In addition, attention should be paid to the dialectical relationship between the solution. Such as: products the depression, sometimes to raise he melt temperature, sometimes to reduce the melt temperature; sometimes to increase the quantity, and sometimes to reduce the feeding amount. To recognize the reverse feasibility of measures to solve the problem.The plastic injection shaper takes shape the cycle quickly by it, to each kind of plastic processing compatible, the size is precise as well as the automaticity higher merit, obtained the widespread use.The injection molding machine working principle is: the granular plastic through a hopper into auger screw rotation, the material to move forward, while the outer screw are equipped with an electric heater, and the the plastic melted mucus state, before this, the mold clampingmechanismthe mold has been closed, when a certain pressure of the material in front of the propeller, the injection of the liquid feed high pressure rapidly injected into the mold cavity mold holding pressure cooling to a certain period of time after the molding of plastic products bythe ejection mechanism Ejection, thus completing a working cycle.The work cycle of the injection machine as:Spotting→ injection →Holding pressure→ cooling →Mold → Ejection→ The screw preplastication feedClamping action is divided into: Quick clamping slow clamping clamping. Clamping time is longer, this time until the mold clampingstage.Use and the status quoThe injection molding machine has a complex shape, size, precision, orwith metal inserts, texture, dense plastics molding, widely used in defense, electromechanical, automotive, transportation, building materials, packaging, agriculture, culture, education, health and people daily life in various fields. China's plastics processing enterprises Xing Luo cloth across the country, the skill levels of the equipment, the equipment of most of the processing enterprises need technological innovation. Inrecent years, China's press industry's technological progress is very significant, especially the gap between the technological level of the injection molding machine with foreign brand names is greatly reduced, and made a significant change in the level ofcontrol, internal quality and appearance. Select the domestic equipment, a smaller investment, also can produce the quality of imported equipment products. These create the conditions for the technological transformation of enterprises. , China Injection Molding Machine Development of China's production of injection molding machine manufacturers more, according to incomplete statistics, more than 60. The structure of the injection molding machine with vertical and horizontal. Press to produce the products can be divided into common type and precision injection molding machine. An injection volume of 45-51000g; 200-36000kN The clamping force; processing raw materials, thermosetting plastics, thermoplastics and rubber three. Thermoplastics, including polystyrene, olyethylene, polypropylene, nylon, polyurethane, polycarbonate, acrylic, polysulfone and (acrylonitrile / butadiene / styrene) copolymer (ABS). From the processed products, monochrome, color and general and precision plastic products. Of the major manufacturers of these products has its own series, each with its own characteristics. Such as Guangdong Chen De Plastics Machinery Co., Ltd. Jie tyrants CJ Series injection molding machine for each specification aretwo forms of numerical control and computer control. Again, Zhejiang Province, Ningbo Haitian Machinery Co., Ltd. the production HTF80X-HFT3600X series injection molding machine can be used for the production of various high-precision thermal plastic, the machine uses linear movement sensors to control the injection mold, ejector, using multiple CPU power control systems, large format color LED display, automatic control of the entire computer. Ordinary horizontal injection molding machine is still the dominant direction of the injection molding machine, its basic structure is almost no major changes in addition to continue to improve its control and level of automation,reducing energy consumption, manufacturers according to market changes is the combination of series direction as a model of the injection molding machine configuration, the small three injection device, a combination of standard and combination, increase flexibility, expanding the scope of use, and improve economic efficiency. ? In recent years, industrial countries in the world of injection molding machine manufacturer in the continuous improvement of the supporting capacity of the function, quality of ordinary injection molding machines, auxiliary equipment, as well as the level of automation. Vigorously develop the development of large injection molding machines, injection molding machines, reaction injection molding machines and precision injection molding machines to meet the production of plastic alloys, magneticplastic, with the demand for plastic products inserts. The injection molding machine is one of the fastest, the gap between the level of industrial countries small presses varieties of the pace of development in China's plastics machinery. But mainly refers to the ordinary injection molding machine, in most varieties of extra large, a variety of special, dedicated, precision injection molding machine, and some still blank, which is the main gap with industrial countriesKey word: Plastic injection shaper, hydraulic system, hydraulic pump, hydraulic cylinder, hydraulic valv.注射成型机液压系统注射成型机注射成型机是塑料机械的一种，简称注射机或注塑机，是将热塑性塑料或热固性料利用塑料成型模具制成各种形状的塑料制品的主要成型设备。
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。
塑料注射成型设计外文文献翻译、中英文翻译、外文翻译
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 in molding production．②For 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 (Fig．4．2．1)．A typical injection molding cycle or sequence consists of five phases：①Injection or mold filling②Packing or compression③Holding④Cooling⑤Part ejectionFig.4.2.1 Injection molding processPlastic granules are fed into the hopper and through an opening 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 builds up，the rotating screw is forced backward until enough plastic has accumulated to make the shot．he 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 colc mold surfaces，it solidifies(freezes)rapidly to produce the skin layer．Since the core remains in the molten state，plastic flows through the core to complete mold filling．Typically，the cavity，is filled to 9 5％～9 8％during injection．Then the molding process is switched over to the packing phaseEven 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．③To compensate for shrinkage，addition plastic is forced into the cavity．Oncethe 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 melt．After the holding stage is completed，the cooling phase starts．During cooling，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 shot is made，plastication ceases．This should occur immediately before the end of the cooling phase．Then the mold opens and the part is ejected．Blow MoldingThe rapid growth in the use of advanced materials in a large number of highly demanding automotive,electronic and cunsumer goods applications has promoted the development of new and more complex material forming processes. In the last twenty years injection molding and blow molding have seen a rapid growth due to the development of new application and packaging industries,. this success can be traced to the optimization of existing processes and to the development of new processing techniques employing novel concepts, injection molding has seen the introduction of techniques such as co-injection ,gas assisted injection molding ,lost core molding and injection/compression.(a)Parison extrusion stage (b)Clamping and blowing stageFig.4.2.2 Extrusion blow moldingBlow molding has been able to deal with much more complex parts through the development of 3D and sequential blow molding , complex molds for deepdrawn parts and cryogenic mold cooling . The introduction of new materials has also made possible the production of parts having multilayer structureThe complexity of these new molding techniques calls for a much better understanding of the material behavior during the basic stages of the process and its relation to the properies and performance of the final part, which are directly dependent upon die and mold designs and on the operating conditions during extrusion , injection ,inflation and cooling in the mold. It is in these areas that the computer simulation fot the coupled phenoment of fluid flow and heat transfer has proven to be a very valuable tool for the equipment manufacturer,mold designer and process engineer!Blow molding processBlow molding can be carried reciprocating screw injection machine．About either on an extruder or asection of molten polymer tubing (parsion) is extruded into an open mold．By means of compressed air or steam the plastic is then blown into the configuration of the mold．This technique is widely used for the manufacture of bottles and similar articles．In the case of large articles，such as liter beverage bottles，the parison may previously have beeninjection molded and oriented to provide additional strength to the final blown piece．In the extrusion blow molding process(Fig．4．2．2)，the raw material is fed to a plasticating extruder in granular or pellet form．The plastic is melted by heat which is transferred through the barrel by the shearing motion of the extruder screw．The helical flights of the screw change configuration along its length from input to output(solids conveying,melting and metering sections)to assure a uniformly homogeneous melt at the screw tip．In continuous extrusion blow molding，the screw feeds the melt directly into the head-die assembly．The meit flows around the mandrel and into an annular die of the convergent or divergent type．A hollow tube or“parison”is extruded continuouslv and cut at preset time intervals for transfer into the blow mold．In the case of intermittent extrusion blow molding，the extruder feeds the material to an accumulator／head device．Once the desired volume has accumulated a ram or plunger pushes the material rapidly through the head-die assembly．The mold clamp mechanism does not need to transfer to a blowing station．The next parison is only extruded after the part is blown，cooled and removed from the mold．Once a parison of the desired length has been formed，the mold is closed and the parison is inflated by internal air introduced through the die-head assembly．The mold walls are vented，and a vacuum may be applied．The molten polymer is thus forced to conform to the shape of the mold cavity．The article iS then cooled，solidified and ej ected from the mold．In both methods the annular die may be designed to incorporate a hydraulic mechanism to vary or program the annular gap size．In this way，the extrusion process can be programmed to impart a specific wall thickness distribution or controlled weight to the parison．Injection／stretch blow molding(Fig．4．2．3)is a two—stage process．In the first stage，the material is injection molded around a core rod to form a preform．In the second stage，the preform is then stretched through the action of a stretch rod，inflated and cooled in much the same manner as in the extrusion blow molding process．The result is a lighter product biaxially oriented in the axial and radial directions．Biaxial orientation provides increasedtensile strength(top load)，less gas，liquid and odour permeation due to an increased molecular alignment and improved drop impact，clarity and light weighting of the container．Injection ／stretch blow molding also produces scrap—free，close-tolerance，completely finished bottles or containers that require no secondary operations．Preform design and its relationship to the final container properties remain one of the most critical aspects of the process．The part thickness distribution has to be mapped onto the preform and through the knowledge of the material properties (degree of crystallinity and shrinkage after molding；stretching characteristics and their temperature dependence among others) the preform dimensions(form and thickness distribution)can be established．(a)P reform injection stage (b)Stretching and blowing stagesFig.4.2.3 Injection/stretch blow molding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。
Autodesk Simulation Moldflow 塑料注射模具注射模拟软件说明书
Plastics made perfect.Autodesk®Simulation Moldflow®Plastic injection moldingsimulation of a concept consumer printer. Designed in Autodesk ® Inventor ® software. Simulated in Autodesk ® Simulation Moldflow ® software. Rendered in Autodesk ® 3ds Max ® software.11Autodesk ® Simulation Moldflow ® plastic injection molding software, part of the Autodesk Simulation solution for Digital Prototyping, provides tools that help manufacturers predict, optimize, and validate the design of plastic parts, injection molds, and e xtrusion dies. Companies worldwide use Autodesk ® Simulation Moldflow ® Adviser and Autodesk ® Simulation Moldflow ® Insight software to help reduce the need for costly physical proto-types, reduce potential manufacturing defects, and get innovative products to market faster.Autodesk Simulation Moldflow Product Line Autodesk is dedicated to providing a wide range of injection molding simulation tools to help CAE analysts, designers, engineers, mold makers, and molding professionals create more accurate digital prototypes and bring better products to market at less cost.Validation and Optimization of Plastic PartsInnovative plastic resins and functional plastic part designs are on the rise in almost every industry. Plastics and fiber-filled composites answer growing pressures to reduce costs and cut time to market. The need for simulation tools that provide deep insight into the plastic injection molding process hasnever been greater.2Hot Runner SystemsModel hot runner system components and set up sequential valve gates to help eliminate weld lines and control the packing phase.Plastic Flow SimulationSimulate the flow of melted plastic to help optimize plastic part and injection mold designs, reduce potential part defects, and improve the molding process.Part DefectsDetermine potential part defects such as weld lines, air traps, and sink marks, then rework designs to help avoid these problems.Thermoplastic FillingSimulate the filling phase of the thermoplasticinjection molding process to help predict the flow of melted plastic and fill mold cavities uniformly; avoid short shots; and eliminate, minimize, or reposition weld lines and air traps.Thermoplastic PackingOptimize packing profiles and visualize magnitude and distribution of volumetric shrinkage to help minimize plastic part warpage and reduce defectssuch as sink marks.Part Layout SimulationValidate and optimize plastic parts, injection molds, resinselection, and the injection molding process.Feed System SimulationModel and optimize hot and cold runner systems and gating configurations. Improve part surfaces, minimize part warpage, and reduce cycle times.Gate LocationIdentify up to 10 gate locations simultaneously. Minimize injection pressure and exclude specific areas when determining gate location.Runner Design WizardCreate feed systems based on inputs for layout, size, and type of components, such as sprues, runners, and gates.Balancing RunnersBalance runner systems of single-cavity, multicavity, and family mold layouts so parts fill simultaneously,reducing stress levels and volume of material.3Mold Cooling SimulationImprove cooling system efficiency, minimize part warpage, achieve smooth surfaces, and reduce cycle times.Cooling Component ModelingAnalyze a mold’s cooling system efficiency.Model cooling circuits, baffles, bubblers, and mold inserts and bases.Cooling System AnalysisOptimize mold and cooling circuit designs to help achieve uniform part cooling, minimize cycle times, reduce part warpage, and decrease manufacturing costs.WarpagePredict warpage resulting from process-induced stresses. Identify where warpage might occur and optimize part and mold design, materialchoice, and processing parameters to help control part deformation.Core Shift ControlMinimize the movement of mold cores by deter-mining ideal processing conditions for injection pressure, packing profile, and gate locations.Fiber Orientation and BreakageControl fiber orientation within plastics to help reduce part shrinkage and warpage across the molded part.CAE Data ExchangeValidate and optimize plastic part designs using tools to exchange data with mechanical simulation software. CAE data exchange is available with Autodesk ® Simulation, ANSYS ®, and Abaqus ®software to predict the real-life behavior of plasticparts by using as-manufactured material properties.Rapid Heat Cycle MoldingSet up variable mold surface temperature profiles to maintain warmer temperatures during filling to achieve smooth surfaces; reduce temperatures in the packing and cooling phases to help freeze parts and decrease cycle times.Shrinkage and Warpage SimulationEvaluate plastic part and injection mold designs to help control shrinkage and warpage.ShrinkageMeet part tolerances by predicting part shrinkage based on processing parameters and grade-specificmaterial data.4Thermoset Flow SimulationSimulate thermoset injection molding, RIM/SRIM, resin transfer molding, and rubber compound injection molding.Reactive Injection MoldingPredict how molds will fill with or without fiber-reinforced preforms. Help avoid short shots due to pregelation of resin, and identify air traps and problematic weld lines. Balance runner systems, select molding machine size, and evaluate thermoset materials.Microchip EncapsulationSimulate encapsulation of semiconductor chips with reactive resins and the interconnectivity of electrical chips. Predict bonding wire deformation within the cavity and shifting of the lead frame due to pressure imbalances.Underfill EncapsulationSimulate flip-chip encapsulation to predictmaterial flow in the cavity between the chip andthe substrate.Specialized Simulation ToolsSolve design challenges with simulation.Insert OvermoldingRun an insert overmolding simulation to helpdetermine the impact of mold inserts on melt flow, cooling rate, and part warpage.Two-Shot Sequential OvermoldingSimulate the two-shot sequential overmolding process: one part is filled; the tool opens and indexes to a new position; and a second part is molded over the first.BirefringencePredict optical performance of an injection-molded plastic part by evaluating refractive index changes that result from process-induced stresses. Evaluate multiple materials, processing conditions, and gate and runner designs to help control birefringence in the part.MuCell ®MuCell ® (from Trexel, Inc.) simulation results include filling pattern, injection pressure, and cell size. These are all critical factors in optimizing a given part for the process, as well as theprocess itself.Specialized Molding ProcessesSimulate a wide range of plastic injection molding processes and specialized process applications.Gas-Assisted Injection MoldingDetermine where to position polymer and gas entrances, how much plastic to inject prior to gas injection, and how to optimize size and placement of gas channels.Co-Injection MoldingVisualize the advancement of skin and core materials in the cavity and view the dynamic relationship between the two materials as filling progresses. Optimize material combinations while maximizing the product's cost-performance ratio.Injection-Compression MoldingSimulate simultaneous or sequential polymer injection and mold compression. Evaluate material candidates, part and mold design,and processing conditions.5CAD Interoperability and MeshingUse tools for native CAD model translation and optimization. Autodesk Simulation Moldflow provides geometry support for thin-walled parts and thick and solid applications. Select meshtype based on desired simulation accuracy and solution time.CAD Solid ModelsImport and mesh solid geometry from Parasolid ®-based CAD systems, Autodesk ® Inventor ® software, CATIA ® V%, Pro/ENGINEER ®, Creo ® Elements/Pro, Autodesk ® Alias ®, Siemens ® NX ®, Rhino ®, and SolidWorks ®, as well as ACIS®, IGES, and STEP universal files.Error Checking and RepairScan imported geometry and automatically fix defects that can occur when translating a model from CAD software.Centerline Import/ExportImport and export feed system and coolingchannel centerlines from and to CAD software, to help decrease modeling time and avoid runner and cooling channel modeling errors.Autodesk Simulation Moldflow CAD Doctor Check, correct, heal, and simplify solid models imported from 3D CAD systems to prepare for simulation.3D SimulationsPerform 3D simulations on complex geometry using a solid, tetrahedral, finite element mesh technique. This approach is ideal for electrical connectors, thick structural components, and geometries with thickness variations.Dual Domain TechnologySimulate solid models of thin-walled parts using Dual Domain™ technology. Work directly from 3D solid CAD models, leading to easier simulation of design iterations.Midplane MeshesGenerate 2D planar surface meshes with assignedthicknesses for thin-walled parts.6Results Interpretation and PresentationUse a wide range of tools for model visualization, results evaluation, and presentation.Results AdviserQuery regions of a model to identify primary causes of short shots and poor part or cooling quality. Get suggestions on how to correct the part, mold, or process.Photorealistic Defect VisualizationIntegration with Autodesk ® Showcase ® software enhances quality assessments of plastic parts by examining near-photorealistic renderings of digital prototypes.Automatic Reporting ToolsUse the Report Generation wizard to create web-based reports. Prepare and share simulation results more quickly and easily with customers, vendors, and team members.Microsoft Office Export CapabilityExport results and images for use in Microsoft ® Word reports and PowerPoint ® presentations.Autodesk Simulation Moldflow Communicator Collaborate with manufacturing personnel, procurement engineers, suppliers, and external customers using Autodesk ® Simulation Moldflow ® Communicator software. Use the Autodesk Simulation Moldflow Communicator resultsviewer to export results from Autodesk Simulation Moldflow software so stakeholders can more easily visualize, quantify, and compare simulation results.Material DataImprove simulation accuracy with precise material data.Material DatabaseUse the built-in material database of grade- specific information on more than 8,500 plastic materials characterized for use in plastic injection molding simulation.Autodesk Simulation Moldflow Plastics Labs Get plastic material testing services, expert data-fitting services, and extensive material databases with the Autodesk ® Simulation Moldflow ® Plastics Labs.Productivity ToolsUse advisers and extensive help to boost productivity.Cost AdviserLearn what drives part costs to help minimize those costs. Estimate product costs based on material choice, cycle time, post-molding operations, and fixed costs.Design AdviserQuickly identify areas of plastic parts that violate design guidelines related to the injection molding process.HelpGet help on a results plot, including information on what to look for and how to correct typical problems. Learn more about solver theory, interpreting simulation results, and designing better plastic parts and injection molds.Results Evaluation and Productivity ToolsVisualize and evaluate simulation results, and use automatic reporting tools to share the results with stakeholders. Take advantage of features such as a material database and advisersto further boost productivity.Automation and CustomizationAutomate common tasks and customize Autodesk Simulation Moldflow software for your organization.API ToolsApplication programming interface (API) tools enable you to automate common tasks, customize the user interface, work with third-party applications, and help implement corporatestandards and best practices.Feature ComparisonCompare the features of Autodesk Simulation Moldflow products to learn how Autodesk Simulation Moldflow Adviser and Autodesk Simulation Moldflow Insight software can help meet the needs of your organization.78。
注塑成型过程外文文献翻译、中英文翻译
附录 1：外文翻译介绍如今塑料在日常生活中占据着极其重要的地位。
如果我们说，没有哪个领域的塑料没有不经过制造中直接到宇宙飞船的生产中，这一点也不夸张。
在19 世纪中叶，塑料开始在材料和生活中起主导作用。
耐腐蚀性是塑料甚至成为金属和提高制造生产率方面受到了很高的关注。
从塑料的紧缺，因此在塑料产品设计等各个方面发生巨大的变革,在制造加工领域还在测试阶段,现在,由于很多人最后通过体力劳动取得了卓越的成效,另外人工智能的帮助下,开发出了CAD / CAM 软件。
由于高强度的重量比，提高了化学稳定性和耐温性，具有耐热和耐腐蚀的特性，光泽性使其成为材料更好的选择。
塑料在形成过程中消耗的能量更少，并且可以被循环利用。
今天，塑料正在取代黄铜、铜、铸铁、钢铁等金属。
塑料可以根据制造方法分类，在加热时软化，在冷却时凝固。
这些被称为“热塑性塑料”，以及那些由于化学变化而变硬的物质。
这些被称为热固性或混合型塑料材料成为产品选择特殊材料是另一个重要因素。
这对于产品的确定是非常必要的。
它也应该能够承受压力。
每种材料都有自己的属性。
一些材料在高环境和耐磨性方面比较好。
困难的是找到一种合适材料，它将完全满足整个要求。
所以材料应该是通用的，它适合我们产品的所有考虑条件和要求。
在考虑了所有这些点的材料之后，必须选择合适的材料来满足所有这些条件。
注塑成型过程它是一种通过将熔融状态的物质注入模具来生产零件的生产工艺。
注射成型被用在很多领域进行生产，包括金属、眼镜、弹性体、糖果以及最常见的热塑性塑料和热固性塑料。
将材料的一部分送入一个加热的桶，混合，并用高压压入一个模腔，它是可以冷却和硬化地方。
在产品设计后，通常由工业设计师或工程师设计模具，模具由模具制造商(或工具制造商)制造，通常由金属或铝制成，并经过精密加工以形成所需的特性。
注塑成型广泛应用于制造各种零件，从最小的零件到汽车的整个车身。
零件的形状和特点、模具的所需材料，以及造型机的性能都必须考虑在内。
注射成型外文翻译、中英文翻译、外文文献翻译
Injection MoldingThe basic concept of injection molding revolves around the ability of a thermoplastic material to be softened by heat and to harden when cooled .In most operations ,granular material (the plastic resin) is fed into one end of the cylinder (usually through a feeding device known as a hopper ),heated, and softened(plasticized or plasticated),forced out the other end of the cylinder,while it is still in the form of a melt,through a nozzle into a relatively cool mold held closed under pressure.Here,the melt cools and hardens until fully set-up.The mold is then opened,the piece ejected,and the sequence repeated.Thus,the significant elements of an injection molding machine become :1)the way in which the melt is plasticized (softened) and forced into the mold (called the injection unit); 2)the system for opening the mold and closing it under pressure (called the clamping unit);3)the type of mold used;4)the machine controls.The part of an injection-molding machine,which converts a plastic material from a sold phase to homogeneous seni-liguid phase by raising its temperature .This unit maintains the material at a present temperature and force it through the injection unit nozzle into a mold .The plunger is a combination of the injection and plasticizing device in which a heating chamber is mounted between the plunger and mold. This chamber heats the plastic material by conduction .The plunger,on each storke; pushes unmelted plastic material into the chamber ,which in turn forces plastic melt at the front of the chamber out through the nozzleThe part of an injection molding machine in which the mold is mounted,and which provides the motion and force to open and close the mold and to hold the mold close with force during injection .This unit can also provide other features necessary for the effective functioning of the molding operation .Moving plate is the member of the clamping unit,which is moved toward a stationary member.the moving section of the mold is bolted to this moving plate .This member usually includes the ejector holesand moldmounting pattern of blot holes or “T” slots .Stationary plate is the fixed member of the clamping unit on which the stationary section of the mold is bolted .This member usually includes a mold-mounting pat tern of boles or “T” slots.Tie rods are member of the clamping force actuating mechanism that serve as the tension member of the clamp when it is holding the mold closed.They also serve as a gutde member for the movable plate .Ejector is a provision in the clamping unit that actuates a mechanism within the mold to eject the molded part(s) from the mold .The ejection actuating force may be applied hydraulically or pneumatically by a cylinder(s) attached to the moving plate ,or mechanically by the opening storke of the moving plate.Methods of melting and injecting the plastic differ from one machine to another and are constantly being improred .couventional machines use a cylinder and piston to do both jobs .This method simplifies machine construction but makes control of injection temperatures and pressures an inherently difficult problem .Other machines use a plastcating extruder to melt the plastic and piston to inject it while some hare been designed to use a screw for both jobs :Nowadays,sixty percent of the machines use a reciprocating screw,35% a plunger (concentrated in the smaller machine size),and 5%a screw pot.Many of the problems connected with in jection molding arises because the densities of polymers change so markedly with temperature and pressure.Athigh temperatures,the density of a polymer is considerably cower than at room temperature,provided the pressure is the same.Therefore,if modls were filled at atmospheric pressure, “shrinkage”would make the molding deviate form the shape of the mold.To compensate for this poor effect, molds are filled at high pressure.The pressure compresses the polymer and allows more materials to flow into the mold,shrinkage is reduced and better quality moldings are produced.Cludes a mold-mounting pattern of bolt holes or “T” slots.Tie rods are members of the clamping force actuatingmachanism that serve as the tension members of clamp when it is holding the mold closed.Ejector is a provision in the claming unit that actuates a mechanism within the mold to eject themolded part(s) form the mold.The ejection actuating force may be applied hydraulically or pneumatically by a cylinder(s) attached to the moving plate,or mechanically by the opening stroke of the moving plate.The function of a mold is twofold :imparting the desired shape to the plasticized polymer and cooling the injection molded part.It is basically made up of two sets of components :the cavities and cores and the base in which the cavities and cores are mounted. The mold ,which contains one or more cavities,consists of two basic parts :(1) a stationary molds half one the side where the plastic is injected,(2)Amoving half on the closing or ejector side of the machine. The separation between the two mold halves is called the parting line.In some cases the cavity is partly in the stationary and partly in the moving section.The size and weight of the molded parts limit the number of cavities in the mold and also determine the machinery capacity required.The mold components and their functions are as following :(1)Mold Base-Hold cavity(cavities) in fixed ,correct position relative tomachine nozzle .(2)Guide Pins-Maintain Proper alignment of entry into mold intrior .(3)Sprue Bushing(sprue)-Provide means of entry into mold interior .(4)Runners-Conrey molten plastic from sprue to cavities .(5)Gates-Control flow into cavities.(6)Cavity(female) and Force(male)-Contorl the size,shape and surface of moldarticle.(7)Water Channels-Control the temperature of mold surfaces to chill plastic torigid state.(8)Side (actuated by came,gears or hydraulic cylinders)-Form sideholes,slots,undercuts and threaded sections.注射成型注射成型的基本概念是使热塑性材料在受热时熔融，冷却时硬化，在大部分加工中，粒状材料（即塑料树脂）从料筒的一端（通常通过一个叫做“料斗”的进料装置）送进，受热并熔融（即塑化或增塑），然后当材料还是溶体时，通过一个喷嘴从料筒的另一端挤到一个相对较冷的压和封闭的模子里。
三维注塑模具设计研究方法和工作流程范文
三维注塑模具设计研究方法和工作流程范文文档下载说明Download tips: This document is carefully compiled by this editor. I hope that after you download it, it can help you solve practical problems. The document 三维注塑模具设计研究方法和工作流程范文can be customized and modified after downloading, please adjust and use it according to actual needs, thank you! In addition, this shop provides you with various types of practical materials, such as educational essays, diary appreciation, sentence excerpts, ancient poems, classic articles, topic composition, work summary, word parsing, copy excerpts, other materials and so on, want to know different data formats and writing methods, please pay attention!三维注塑模具设计是一个复杂而关键的工程领域，它涉及到从概念到实际生产的全过程。
在这篇文章中，我们将介绍三维注塑模具设计的研究方法和工作流程，以便读者更好地了解这一领域。
一、引言。
三维注塑模具设计是一项综合性工程，它要求设计师具备丰富的经验和专业知识。
在进行三维注塑模具设计之前，设计师需要对产品的形状、尺寸、材料等进行全面的了解，并根据这些信息确定合适的设计方案。
微通道注塑成型模具设计外文文献翻译、中英文翻译
附录1：外文翻译微通道注塑成型模具设计大规模生产微流体装置对于其中的生物医学应用是重要的一次性设备被广泛使用。
注射成型是一种众所周知的生产方法的设备以大规模低成本。
在这项研究中，注塑过程适用于制造具有单个微通道的微流体装置。
至提高产品质量，采用高精度机械加工制造的微流体装置的模具。
常规注塑机是在这个过程中实现的。
在不同的模具温度下进行注模。
通过测量部件变形来表征注射件的翘曲。
评估了模具温度对最终装置质量的影响在零件变形和粘接质量方面。
从实验结果来看，翘曲和模制件的粘合质量之间的一致性被观察。
发现随着片的翘曲减小，粘接质量下降增加。
接合断裂压力的最大值和最小值在相同的模具温度下发现翘曲点。
这个模具温度被命名为设计的微流体装置的最佳温度。
它是观察到在45℃的模具温度下产生的微流体装置能够承受高达74巴的压力1介绍微流体装置的微尺度和纳米级制造是一种学术研究和行业的热门话题。
重复，高效，大规模生产的微流体装置是对于一次性设备的生物医学应用而言至关重要广泛使用。
当微流体装置的制造是关心，基本上有两种常见的方法：直接基板制造和基于模具的技术。
直接底物制造包括蚀刻，激光烧蚀和机械加工。
另一方面，基于模具的技术包括软光刻，热压花和注射成型。
虽然模具的制造可能是复杂的;一旦模具该模具可以很好地被使用好几次。
之后完成模具，其余的制造程序是简单且高度可重现（即，低成本复制）使基于模具的技术非常适合批量生产。
在基于模具的技术中，注塑成型是一个很好的成型宏观尺度的制造工艺（尺寸大于毫米），其中熔化的材料被注入进入模具以获得所需的形状。
使用的材料一般通过陶瓷和金属的塑料也可以用塑料模塑粘合剂。
在此过程中，材料被供应到加热桶，混合，并强制进入其中冷却的模具腔并根据腔体的形状固化[1]。
一旦已经制造了一个模具，可以有几千个零件模仿了很少或没有额外的努力。
产品好尺寸公差和过程几乎不需要完成对最终产品的操作。
考虑到这些方面，注射成型是制造零件的流行制造工艺在大规模上广泛应用于航空航天，汽车，医疗，玩具和光学[2]。
注射成型外文文献翻译、塑料模具类外文翻译、中英文翻译
2.3注射成型2.31注射成型注塑主要用于生产热塑性塑料零件，也是最原始的方法之一。
目前注塑占所有塑料树脂消费量的30%。
典型的注塑成型产品“塑料杯、容器、外壳、工具手柄、旋钮、电气和通信组件(如电话接收器)、玩具、和水暖配件。
聚合物熔体由于其分子量具有很高的粘度；它们不能像金属液在重力的条件下倒进模,必须在高压力下注入模具。
因此,金属铸造的力学性能是由模具壁传热的速度决定，同时也决定了在最终铸件的晶粒尺寸和晶粒取向, 高压注射成型过程中熔体的注射剪切力产生的主要原因是材料最后的分子取向。
力学性能影响成品都是因为在模具里的注塑条件很冷却条件。
注塑已应用于热塑性塑料和热固性材料,发泡部分,也已被修改过用于展现注射成型（RIM）反应过程，其中有两个部分组成，一种是热固性树脂体系，另一种是聚合物快速注射模具。
然而大多数注射成型是热塑性塑料,后面的讨论集中于这样的模型。
一个典型的注塑周期或序列由五个阶段组成(见图2 - 1):注射或模具填充;(2) 包装或压缩;(3) 保持;(4) 冷却;(5)部分排除物图2 - 1注射成型过程塑料颗粒（或粉末）被装入进料斗并通过注塑缸上的开口在那里它们被旋转螺杆结转。
螺杆的旋转使颗粒处于高压下加上受热缸壁使它们融化。
加热温度范围从265到500°F。
随着压力的增大,旋转螺丝被迫向后,直到积累了足够的塑料可以进行注射。
注射活塞(或螺钉)迫使熔融塑料从料桶通过喷嘴、浇口和流道系统,最后进入模腔。
在注射过程中,熔融塑料充满模具型腔。
当塑料接触冷模具表面,它迅速凝固(冻结)产生皮肤层。
由于核心仍在熔融状态,塑料流经核心来完成填充。
一般的，该空腔被注入期间填充到95％?98％。
然后成型工艺转向了填充的阶段。
型腔填充后，熔融塑料开始冷却。
由于冷却塑料会收缩产生缺陷，如缩孔、气泡，而且空间存在不稳定性。
所以被迫实行空穴用来补偿收缩、添加塑料。
一旦模腔被填充，压力应用熔体防止腔内熔融塑料会流进浇口。
4 流动注射
4.2 基本原理
China University of Geosciences
注意： 流 动 注 射 分 析
对试样区带在载流中分散状态进行确切的定量 化预测并非易事。影响试样分散的各试验参数早已 为人熟知，但运用已有的流体力学理论建立FIA响 应峰形数学模型的多方努力结果并不十分理想。学 者间对不同表达式的争议有时相当激烈，但往往都 经不住实践的广泛检验。一个实验室的预测和实验 结果，很少能被其他实验室所重复。其主要原因是 还有其它难以在实践中定量控制的因素，如：管道 结构的影响，化学反应的影响等。因此，寻求普遍 适用的FIA响应值的数学表达式几乎是不可能的。
4.1 概 述
FIA的特点：
流 动 注 射 分 析
广泛的适应性； 高效率； 低消耗； 高精度； 设备简单，价廉。
微量技术 试样10-100μl 节约试剂90％99%
China University of Geosciences
4.1 概 述
FIA的特点：
流 动 注 射 分 析
流 模仿手工操作间歇式自 动 动分析系统1940s 注 射 分 析
图4-1 间歇式自动分析示意图
气泡间隔式连续流动分 析系统1950s
图4-2 连续流动分析示意图
China University of Geosciences
4.1 概 述
意义：
流 动 注 射 分 析 第一次把分析试样与试剂从传统的试管、 烧杯等容器中转入管道中，试样与试剂在连 续流动中完成物理混合与化学反应，大大提 高了分析效率，对化学实验室中溶液处理操 作的变革起到了推动作用。
China University of Geosciences
4.3 仪器装置
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附录Numerical Filling Simulation of Injection MoldingUsing Three—Dimensional ModelAbstract：Most injection molded parts are three-dimensional, with complex geometrical configurations and thick／thin wall sections．A 3D simulation model will predict more accurately the filling process than a 2.5D mode1.This paper gives a mathematical model and numeric method based on 3D model，in which an equal-order velocity-pressure interpolation method is employed successfully．The relation between velocity and pressure is obtained from the discretized momentum equations in order to derive the pressure equation．A 3D control volume scheme is employed to track the flow front．The validity of the model has been tested through the an analysis of the flow in cavity．Key words：three dimension；equal-order interpolation；simulation；injection molding1 IntroductionDuring injection molding，the theological response of polymer melts is generally non-Newtonian and no isothermal with the position of the moving flow front．Because of these inherent factors，it is difficult to analyze the filling process．Therefore，simplifications usually are used．For example，in middle-plane technique and dual domain technique[1], because the most injection molded parts have the characteristic of being thin but generally of complex shape，the Hele-Shaw approximation [2] is used while an analyzing the flow, i.e.．The variations of velocity and pressure in the gapwise (thickness) dimension are neglected．So these two techniques are both 2.5D mold filling models，in which the filling of a mold cavity becomes a 2D problem in flow direction and a 1D problem in thickness direction．However, because of the us e of the Hele-Shaw approximation，the information that 2.5D models can generate is limited and incomplete．The variation in the gapwise (thickness) dimension of the physical quantities with the exception of the temperature，which is solved by finite difference method，is neglected．With the development of molding techniques，molded华东交通大学理工学院毕业设计（论文）parts will have more and more complex geometry and the difference in the thickness will be more and more notable，so the change in the gapwise (thickness) dimension of the physical quantities can not be neglected．In addition，the flow simulated looks unrealistic in as much as the melt polymer flows only on surfaces of cavity, which appears more obvious when the flow simulation is displayed in a mould cavity．3D simulation model has been a research direction and hot spot in the scope of simulation for plastic injection molding．In 3D simulation model，velocity in the gapwise (thickness) dimension is not neglected and the pressure varies in the direction of part thickness，and 3 D finite elements are used to discretize the part geometry．After calculating，complete data are obtained(not only surface data but also internal data are obtained)．Therefore, a 3D simulation model should be able to generate complementary and more detailed information related to the flow characteristics and stress distributions in thin molded parts than the one obtained when using a 2.5D model(based on the Hele-Shaw approximation)．On the other hand，a 3D model will predict more accurately the characteristics of molded parts having thick walled sections such as encountered in gas assisted injection molding．Several flow behaviors at the flow front．such as “fountain flow”．which 2.5D model cannot predict, can be predicted by 3D mode1. Meanwhile, the flow simulation looks more realistic inasmuch as the overall an analysis result is directly displayed in 3D part geometry or transparent mould cavity．This Paper presents a 3 D finite element model to deal with the three—dimensional flow, which employs an equa1-order velocity-pressure formulation method [3,4]．The relation between velocity and pressure is obtained from the discretized momentum equations, then substituted into the continuity equation to derive pressure equation．A 3D control volume scheme is employed to track the flow front．The validity of the model has been tested through the analysis of the flow in cavity．2 Governing EquationsThe pressure of melt is not very big during filling the cavity, in addition，reasonable mold structure can avoid over big pressure，so the melt is considered incompressible．Inertia and gravitation are neglected as compared to the viscous force．With the above approximation，the governing equations，expressed in cartesian coordinates，are as following：Momentum equationsContinuity equationEnergy equationwhere, x，y，z are three dimensional coordinates and u, v，w are the velocity component in the x, y, z directions．P，T，ρandη denote pressure，temperature, density and viscosty respectively．Cross viscosity model has been used for the simulations：where，n,γ，r are non-Newtonian exponent，shear rate and material constant respectively．Because there is no notable change in the scope of temperature of the melt polymer during filling，Anhenius model[5] for η0 is employed as following：where B，Tb，β are material constants.3 Numerical Simulation Method3.1 Velocity-Pressure RelationIn a 3D model，since the change of the physical quantities are not neglected in the gapwise (thickness) dimension，the momentum equations are much more complex than those in a 2.5D mode1．It is impossible to obtain the velocity—pressure relation by integrating the momentum华东交通大学理工学院毕业设计（论文）equations in the gapwise dimension，which is done in a 2.5D model. The momentum equations must be first discretized，and then the relation between velocity and pressure is derived from it. In this paper, the momentum equations are discretized using Galerkin’s method with bilinear velocity-pressure formulation．The element equations are assembled in the conventional manner to form the discretized global momentum equations and the velocity may be expressed as followingwherethe nodal pressure coefficients are defined aswhere represent global velocity coefficient matrices in the direction of x, y, z coordinate respectively. denote the nodal pressure coefficients thedirection of x, y, z coordinate respectively. The nodal values for are obtained byassembling the element-by-element contributions in the conventional manner. N，is element interpolation and i means global node number and j , is for a node, the amount of the nodes around it.3.2 Pressure EquationSubstitution of the velocity expressions (2) into discretized continuity equation, which is discretized using Galerkin method，yields element equation for pressure:The element pressure equations are assembled the conventional manner to form the global pressure equations．3.3 Boundary ConditionsIn cavity wall, the no- slip boundary conditions are employed, e.g.On an inlet boundary,3.4 Velocity UpdateAfter the pressure field has been obtained，the velocity values are updated using new pressure field because the velocity field obtained by solving momentum equations does not satisfy continuity equation．The velocities are updated using the following relationsThe overall procedure for fluid flow calculations is relaxation iterative，as shown in Fig.l and the calculation is stable without pressure oscillation．3.5 The Tracing of the Flow FrontsThe flow of fluid in the cavity is unsteady and the position of the flow fronts values with time．Like in 2.5D model, in this paper, the control volume method is employed to trace the position of the flow fronts after the FAN(Flow Analysis Network)[6]. But 3D control volume is a special volume and more complex than the 2D control volume．It is required that 3D control volumes of all nodes fill the part cavity without gap and hollow space. Two 3D control volumes are shown in Fig．2．华东交通大学理工学院毕业设计（论文）4 Results and DiscussionThe test cavity and dimensions are shown in Fig.3(a)．The selected material is ABS780 from Kumbo. The pa rametric constants corresponding to then, γ,B, Tb and β of the five-constant Cross-type Viscosity model are 0．2638, 4．514 ×le4 Pa, 1.3198043×le-7 Pa *S, 1．12236 ×1e4K，0．000 Pa-1．Injection temperature is 45℃，mould temperature is 250℃, injection flow rate is 44．82 cu. cm／s. The meshed 3D model of cavity is shown in Fig. 3(b).“Fountain flow” is a typical flow phenomenon during filling．When the fluid is injected into a relatively colder mould，solid layer is formed in the cavity walls because of the diffusion cooling，so the shear near the walls takes place and is zero in the middle of cavity, and the fluid near the walls deflects to move toward the walls．The fluid near the center moves faster than the average across the thickness an d catches up with the front so the shape of the flow front is round like the fountain．The round shape of the flow front of the example in several filling times predicted by present 3D model and shown in Fig．4(a)，conforms to the theory and experiments．Contrarily, the shape of the flow front predicted by 2.5D model and shown in Fig．4(b) do not reveal the“Fountain flow”．The flow front comparison at the filling stage is illustrated in Fig．5．It shows that the predicted results based on present 3D model agree well with that based on Moldflow 3D mode1．The gate pressure is illustrated in Fig．6，compared with the prediction of Moldflow 3D model．It shows that the predicted gate pressure of present 3D model is mainly in agreement with that based on Moldflow 3D mode1．The major reason for this deviation is difference in dealing with the model an d material parameters．华东交通大学理工学院毕业设计（论文）5 ConclusionsA theoretical model and numerical scheme to simulate the filling stage based on a 3D finite element model are presented．A cavity has been employed as example to test the validity. 3D numeral simulation of the filling stage in injection moulding is a development direction in the scope of simulation for plastic injection molding in the future．The long time cost is at present a problem for 3D filling simulation，but with the development of computer hardware and improvement in simulation technique，the 3D technique will be applied widely．华东交通大学理工学院毕业设计（论文）三维注射成型流动模拟的研究摘要:大多数注射成型制品都是具有复杂的几何轮廓和厚壁或薄壁的制品。