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注塑模CAE技术0引言塑料产品从产品设计到成型生产包括塑料制品设计、模具设计、模具制造和注塑工艺参数选择等几个主要方面。传统的注塑模具设计主要依靠设计人员的经验，而注塑成型过程非常复杂，塑料熔体的流动性能千差万别，制品和模具的结构千变万化，工艺条件各不相同，成型缺陷各式各样，模具设计往往需要反复的试模、修模才能投入生产，很少有一次成功的，发现问题后，不仅要重新调整工艺参数，甚至要修改塑料制品和模具，不但费时费力，而且降低了产品的开发速度。而利用注塑模CAE技术可以在模具制造前，模拟注塑过程（包括充填、保压及冷却）并及早发现问题，优化模具设计和工艺条件设定，减少试模次数以提高生产效率，现已成为注塑加工技术的一个重要发展方向。1注塑模CAE技术的历史注塑模CAE技术是根据塑料加工流变学和传热学的基本理论，建立熔体在模具型腔中的流动、传热的物理、数学模型，利用数值计算理论构造其求解方法，利用计算机可视化技术形象、直观地模拟出实际成型中熔体的动态填充、冷却过程的一门分析技术。20世纪60年代，英国、美国和加拿大等国的学者如J.R.Pearson(英)、J.F.Stevenson（美）、M.R.Kamal(加)和K.K.Wang(美)等开展了一系列有关塑料熔体在模具型腔内流动与冷却的基础研究。在合理的简化基础上，60年代完成了一维流动与冷却分析程序，70年代完成了二维冷却分析程序，80年代注塑模CAE技术开始从理论研究进入实用化阶段，开展了三维流动与冷却分析并把研究扩展到保压、纤维分子取向以及翘曲预测等领域。进入90年代后开展了流动、保压、冷却和应力分析等注塑工艺全过程的集成化研究。CAE技术的出现，为注塑模设计提供了可靠的保证，它的应用是模具设计史上的一次重大变革。2注塑模CAE技术的作用利用传统方法设计注塑模具，设计成功与否将很大程度上依赖设计者的经验，而且对复杂零件浇口位置的合理与否，排气槽位置的设置、熔接线位置的确定等都十分困难。模具在交付使用之前一般需经过反复试模修改，直到得到合格的制品为止，从而不可避免地造成了生产周期的延长，而且一般也难以得到最优的设计方案和工艺参数。而利用注塑模CAE技术设计模具则不然，由于在模具设计构思阶段，可利用注塑模CAE 技术进行流动过程模拟，使得通常只有在模具试模阶段才能发现的问题，如短射，熔接线或气孔出现在外观零件表面等问题得以避免。同时帮助设计人员完成诸如流道系统的平衡设计，排气槽的设置，合理确定注塑工艺参数等工作，这样使得通常在必须反复试模修改而确定的模具结构参数和工艺参数在模具设计构思阶段得以确定，缩短了模具设计制造周期、提高了模具设计质量。所以注塑模CAE软件的作用主要表现为：（1）优化塑料制品设计塑料的壁厚、浇口的数量及位置、流道系统的设计等对于塑料制品的质量有重大影响。以往全凭设计者的经验，用手工方法实现，费时费力，而利用CAE技术，可快速设计出最佳的制品。（2）优化塑料模具设计可以对型腔尺寸、浇口位置及数量、流道尺寸和冷却系统等进行优化设计。在计算机上模拟试模、修模和提高模具质量，减少实际试模次数。（3）优化注射工艺参数对注射过程进行模拟，发现可能出现的成型缺陷，确定最佳的注射压力、锁模力、模具温度、熔体温度、注射时间和冷却时间等。由此可见，注塑模CAE技术无论在提高生产率、缩短模具设计制造周期和保证产品质量，还是在降低成本、减轻劳动强度等方面，都具有很大的优越性和重大的技术经济意义。3注塑模CAE软件种类及其简介到目前为止，成熟的商业注塑模CAE软件比较多，Moldflow公司的Moldflow软件和AC-Tech公司（2000年2月，被Moldflow公司合并）的C-Mold软件是其中的优秀代表；另外还有国外的TMCONCEPT、CADMold、Fidap、Stirm100、Polyflow和我国台湾地区的Moldex等软件应用也比较广；而国内在“八五”期间才开始这方面的研究，现在华中理工大学的HSCAE软件和郑州大学的Z-Mold软件在国内处于领先地位。Moldflow软件是专业从事注塑成型CAE软件和咨询的Moldflow公司的系列产品，该公司自1976年发行了世界上第一套注塑模CAE软件以来，一直主导注塑模CAE软件市场。至2004年，Moldflow软件在全球注塑模CAE市场的占有率达75%。MoldFlow软件包括三部分：MoldFlow Plastics Advisers（产品优化顾问，MPA）、 MoldFlow Plastics Insisht（注塑成型模拟分析，MPI）和 MoldFlow Plastics Xpert（注塑成型过程控制专家，MPX）。一般情况下，最常用MPI，主要用来对注塑过程进行模拟，从而得到最佳的浇口数量与位置，合理的流道系统与冷却系统，并对型腔尺寸、浇口尺寸、流道尺寸和冷却系统尺寸进行优化，并且还可对注塑工艺参数进行优化。Moldflow软件的模流分析技术可以分为三种，即Midplane、Fusion和3D。4 Moldflow的Midplane分析技术Midplane（中面流）的应用始于20世纪80年代。其网格是三节点的三角形单元，其原理是将3D几何模型简化成中性面几何模型（即将网格创建在模型壁厚的中间处），利用所建立的中性面进行模拟分析，即以平面流动来仿真三维实体流动。此分析技术发展至今已相当成熟稳定，其优点为分析速度快、效率高。基于中面流技术的注塑流动模拟软件应用的时间最长、范围也最广。但是实践表明，基于中面流技术的模拟软件在应用中具有很大的局限性，具体表现为： (1) 用户必须构造出中面模型。采用手工操作直接由实体模型构造中面模型十分困难，往往需要花费大量的时间，而且不能从其他CAD模型转换。(2) 无法描述一些三维特征。如不能描述惯性效应、重力效应对熔体流动的影响，不能预测喷射现象、熔体前沿的泉涌现象等。(3) 由于CAD阶段使用的产品模型和CAE阶段使用的分析模型不统一，使二次建模不可避免，CAD与CAE系统的集成也无法实现。5 Moldflow的Fusion分析技术Fusion（双面流）分析技术是基于Moldflow的独家专利Dual Domain的分析技术。2000年推出的Fusion分析技术，使得用户不需要抽取中性面就可以进行分析，克服了几何模型的重建问题，大大减轻了用户建模的负担。网格也是三角形单元，而其原理是将模具型腔或制品在厚度方向上分成两部分，有限元网格在型腔或制品的表面产生。在流动过程中，上、下两表面的塑料熔体同时并且协调地流动。显然，Fusion技术的表面网格是基于中性面的，仍无法解决中性面的根本问题，所以双面流技术所应用的原理和方法与中面流所应用的没有本质上的差别，所不同的是双面流采用了一系列相关的算法，将沿中面流动的单股熔体演变为沿上、下表面协调流动的双股流。双面流技术的最大优点是模型的准备时间大大缩短，这样就大大减轻了用户建模的负担，将原来需要几小时甚至几天的建模工作缩短为几分钟。因此，基于双面流技术的模拟软件问世时间虽然只有短短数年，但在全世界却拥有了庞大的用户群，得到了广大用户的支持和好评。但是双面流技术有以下不足：(1) 由于双面流技术没有从根本上解决中性面的问题，所以还是无法描述某些三维特征，如不能描述惯性效应、重力效应对熔体流动的影响，不能预测喷射现象、熔体前沿的泉涌现象等。(2) 上、下对应表面的熔体流动前沿存在差别。由于上、下表面的网格无法一一对应，而且网格形状、方位与大小也不可能完全对称，所以如何将上、下对应表面的熔体流动前沿的差别控制在所允许的范围内是实施双面流技术的难点。(3) 熔体仅沿着上、下表面流动，在厚度方向上未作任何处理，缺乏真实感。6 Moldflow的3D分析技术以上两种技术都忽略了厚度方向的物理量，只是二维的模拟，因而结果不是十分精确。Moldflow公司的3D（三维）分析技术采用了真三维实体模流分析技术，经过严谨的理论推导与反复的验证，将惯性效应、非恒温流体等因素考虑到有限元分析中，熔体厚度方向的物理量变化不再被忽略，能够更全面地描述填充过程的流动现象，使分析结果更能接近现实状况，适用于所有塑件制品。其立体网格是由四节点的四面体单元组成。并采用全新的3D立体显示技术，可快速清楚地显示出模型内、外部的流动场、温度场、应力场和速度场等分析结果。对于上述分析结果也可利用等位线或等位面方式显示，让实体模型内、外部各变量的变化情形显示更清楚，Moldfiow还提供动画的功能，透过3D动画的方式显示塑料熔体在型腔中的流动变化，让用户更直观地看清设计与制造过程中可能遇到的问题。但是3D技术的网格划分要求很高，控制方程更加复杂，计算量大、时间长，计算效率低，不适合开发周期短并需要通过CAE进行反复修改验证的注塑模设计。因此，目前该技术普及率不是很高，不过它最终必将取代中面流技术和双面流技术。7注塑模发展趋势注塑模CAE技术不论从理论上还是在应用上都取得了长足的进步，但在以下几个方面仍有待于进一步完善和发展：（1）数学模型、数值算法逐步完善注塑模CAE技术的实用性，取决于数学模型的准确性及数值算法的精确性。目前的商品化模拟软件模型没有完全考虑物理量在厚度方向上的影响，为了进一步提高软件的分析精度和使用范围，必须进一步完善目前的数学模型和算法。（2）注塑成型全过程模拟目前，注塑成型模拟软件主要有填充、流动、保压、冷却、应力应变和翘曲分析等模块，各模块的开发是基于各自独立的数学模型，这些模型在很大程度上进行了简化，忽略了相互之间的影响。但是，从注塑成型工艺过程来看，塑料熔体的填充、流动、保压和冷却是交织在一起并相互影响的，因此，填充、流动、保压和冷却分析模块必须有机地结合起来，进行耦合分析，才能综合反映注塑成型的真实情况。（3）优化理论及算法，使CAE技术“主动”地优化设计将人工智能技术，如专家系统和神经网络等加入设计计算中，使模拟程序能“智慧”地选择注塑工艺参数、提供修正制品尺寸和冷却管道布置方案，减少人工对程序的干涉。（4）对新的注塑成型方法进行模拟分析目前，在常规注塑成型技术的基础上，又发展出了一些新的注塑成型方法，比如气体辅助注射、薄壁注塑成型、反应注射和共注射等。但是还没有专门针对这些成型方法的模拟软件，所以亟待开发。（5）注塑模CAD/CAE/CAM的集成化与网络化目前的商品化注塑模CAE软件与CAD、CAM软件之间的数据传递主要依靠文件的转换，这容易造成数据的丢失和错误。因此在设计制造过程中采取单一模型，建立注塑模CAD/CAE/CAM系统的统一数据库，加强三者之间的联系是今后的发展方向之一。为适应电子商务的发展要求，这个集成系统将实现异地的“协同设计”和“虚拟制造”。8结束语尽管通过大量的实践证明，在塑料模具工业中引入CAE技术后，大大缩短了模具设计和制造周期，提高了模具的使用寿命和制造精度。同时，CAE技术的出现也使注塑模设计从传统的经验和技艺走上科学化的道路，在一定程度上改变了注塑模传统的生产方式，但目前CAE技术并不能代替人的创造性工作，只能作为一种辅助工具帮助工程师了解方案中存在的问题，还难以提供一个明确的改进方案，仍需通过反复交互（分析修改再分析），才能将设计人员的正确经验体现到模具设计中去，而设计方案的确定很大程度上仍需依靠设计人员的经验和水平。Injection Molding CAE Technology0 Introduction Plastic products from product design to production, including molding plastic products design, mold design, mold manufacturing and injection molding process parameters and several other main areas. The traditional injection mold design mainly rely on the designers experience, while the injection molding process is very complex, plastic melt flow properties of different and ever-changing products and die structure, process conditions vary, forming various defects, mold design often require repeated trial-mode, maintenance mode can be put into production, with little of a successful, identify problems, not only to re-adjust the process parameters, or even to modify the plastic products and molds, not only time-consuming and laborious, but also reduces product development time . The use of injection molding CAE technology in mold manufacturing prior to simulate injection molding process (including filling, packing and cooling) and the early detection of problems, optimize mold design and process conditions set to reduce the number of test mode in order to improve production efficiency, has become a injection molding technology is an important direction of development. 1 The history of Injection Molding CAE technology Injection Molding CAE technology is based on plastics processing rheology and heat transfer of the basic theory, the melt in the mold cavity in the flow, heat transfer physics, mathematical model, using numerical solution method of constructing the theory, the use of computer visualization technology image, visually simulate the dynamics of the actual shape of the melt filling and cooling process, an analysis techniques. The 20th century, 60 years, the United Kingdom, the United States and Canada and other countries of the scholars, such as JRPearson (United Kingdom), JFStevenson (America), MRKamal (Canada) and KKWang (America), etc. to carry out a series of plastic melt in the mold-type cavity flow and cooling of basic research. At a reasonable simplification, based on 60 years completed a one-dimensional flow and cooling analysis programs, 70 years to complete the two-dimensional cooling analysis programs, and 80 years from the injection molding CAE technology has begun to theoretical research into the practical phase, launched a three-dimensional flow and cooling analysis and the study extended to packing, fiber orientation and warpage prediction of molecular and other fields. After 90 years carried out into the flow, packing, cooling and stress analysis, the whole process of injection molding processes are integrated research. CAE technologies, for the injection mold design provides a reliable guarantee that its application is mold design in the history of a major change. 2 The role of Injection Molding CAE technology Using traditional methods of design of injection mold design success will rely heavily on the experience of designers, but also for complex parts gate position is reasonable or not, the location of the exhaust slot settings, to determine the location of weld lines and so very difficult. Die in delivery will normally take before the test mode after repeated changes, until the products have been qualified, which inevitably led to the extension of the production cycle, and generally difficult to obtain an optimal design and process parameters. The use of injection molding CAE technical design, mold is not true, because of mold design concept stage, can make use of CAE technology in injection molding process simulation flow, making usually only in the mold tryout phases in order to find problems, such as short shots, weld lines or holes appear in the surface appearance of parts and other issues have been avoided. While helping the designer to complete the balance of the system, such as flow channel design, exhaust ducts, setting, rationally determine the injection molding process parameters, etc., so that usually makes the modification must be repeated tryout to determine structural parameters of the mold die design and process parameters in the conceptual stage able to determine, reduce the mold design and manufacturing cycle and improve the mold design quality. Therefore, the role of injection molding CAE software, mainly as follows: (1) Optimize design of plastic products Plastic wall thickness, gate number and location of the design of flow channel system for the quality of plastic products have a significant impact. Depends on the experience of the past, designers using manual methods to achieve, time-consuming effort, but the use of CAE technology to quickly design the best products. (2) optimize the plastic mold design Can be cavity size, gate location and number of flow channel dimensions and cooling systems to optimize the design. On the computer simulation test mold, mold repair mold and improve quality and reduce the number of actual tryout. (3) to optimize injection process parameters Simulation of the injection process and found possible shape defects, to determine the best injection pressure, clamping force, mold temperature, melt temperature, injection time and cooling time. This shows that the injection molding CAE technology in terms of improving productivity, reduce mold design and manufacture cycle and to ensure product quality, or reduce costs, reduce labor intensity and so on, have very significant technical advantages and economic significance. 3 Injection Molding CAE software types and their details To date, a mature business are more injection molding CAE software, Moldflow Corporation Moldflow software and AC-Tech, Inc. (February 2000, was Moldflow Merger) and C-Mold software is an excellent representative; There are also foreign The TMCONCEPT, CADMold, Fidap, Stirm100, Polyflow and Chinas Taiwan region Moldex-peer software applications are relatively wide; and domestic in the Eighth Five-Year period began research in this area, and now Huazhong University of Technology HSCAE software and Zhengzhou University, Z -Mold software in China in the leading position. Moldflow software is specialized in injection molding CAE software and consulting for Moldflows range of products, the company issued since 1976, the worlds first set of injection molding CAE software, has been a leading injection molding CAE software market. To 2004, Moldflow Injection Molding CAE software in the global market share of over 75%. MoldFlow software includes three parts: MoldFlow Plastics Advisers (product optimization consultant, MPA), MoldFlow Plastics Insisht (injection molding simulation analysis, MPI), and MoldFlow Plastics Xpert (injection molding process control specialists, MPX). Under normal circumstances, the most commonly used MPI, is mainly used for injection molding process simulation to get the best number and location of the gate, reasonable flow channel system and cooling system, and cavity size, gate size, runner size and cooling systems to optimize the size and the injection molding process parameters may also be optimized. Moldflow Software Moldflow analysis techniques can be divided into three kinds, namely, Midplane, Fusion and 3D . 4 Moldflow analysis of Midplane Midplane (in the surface flow) applications began in the 20th century, the 80s. The grid is a three-node triangular element, its principle is the 3D geometric model of simplified geometric model of the neutral surface (to be created in the model grid the middle of the wall thickness), using established simulation analysis of the neutral surface, ie to flow in plane to simulate three-dimensional solid flow. The analysis of technological development has been very mature and stable, and the advantages for the analysis of speed and high efficiency. Based on the flow of surface flow simulation of injection molding technology, software applications, the longest, widest range. But the practice shows that, based on the surface flow simulation software in the application of technology that has significant limitations, specifically as follows:(1) The user must construct a mid-surface model. Using manual directly from the physical model structure in the surface model is very difficult and often takes a lot of time and can not be converted from other CAD models. (2) can not be described in a number of three-dimensional features. If they can not describe the inertia effect, gravitational effects on melt flow, which fail to predict jet phenomenon, melt the forefront of Quan phenomena. (3) The use of CAD phase of the product model and stages of the use of CAE analysis model is not unified, so that the inevitable second modeling, CAD and CAE systems integration can not be achieved. 5 Moldflows Fusion analysis Fusion (double flow) analysis technique is based on Moldflows patented Dual Domain of analysis techniques. Fusion launched in 2000, analysis techniques, enabling users do not need to extract the neutral surface can be analyzed, to overcome the reconstruction of the geometric model, thus greatly reducing the burden on the user modeling. Grid is also a triangular element, and its principle is to mold cavity or the products in the thickness direction is divided into two parts, finite element mesh on the surface of the cavity or the products. In the flow process, the upper and lower surface of the plastic melt at the same time two and to coordinate movement of the simulation shown .Clearly, Fusion technology, the surface of the grid is based on the neutral surface is still not solve the fundamental problem the neutral surface, so double-sided application of the principle of streaming technologies and methods applied in the surface flow with no difference in the nature, the The difference is two-sided flow using a series of related algorithms, will flow along the surface of the single-stranded melts evolved along the upper and lower surface of the coordination of the flow of dual-stream. Double-sided flow of technologys biggest advantage is that the model greatly shorten the preparation time, thus greatly reducing the burden on the user modeling, will take several hours or even days of the original modeling work reduced to a few minutes. Therefore, based on double-sided flow simulation software technology, although the advent of time, only a few years, but in the world but has a huge user base, get the majority of customers for their support and praise. But the double-sided flow of technology has the following deficiencies: (1) The two-sided flow of technology does not fundamentally resolve the issue of a neutral face, they still can not describe some three-dimensional features, such as the inertial effect can not describe gravity effect on the melt flow, which fail to predict jet phenomenon, melt cutting-edge Quanyong phenomena. (2) the upper and lower surfaces corresponding to the melt flow front there are differences. As the upper and lower surface of the grid can not be one correspondence, but the grid shape, orientation and size can not be completely symmetrical, so how the upper and lower surfaces corresponding to the difference between the melt flow front control is within the scope permitted by Difficulties in the implementation of double-sided streaming technology. (3) melt is only along the upper and lower surface flows, in the thickness direction is not to make any treatment, lack of realism. 6 Moldflows 3D analysis techniques These two techniques have overlooked the thickness direction of the physical quantity, only two-dimensional simulation, and therefore results are not very precise. Moldflow Corporations 3D (3D) analysis technology uses a true three-dimensional solid model flow analysis techniques, through rigorous theoretical derivation and repeated verification, the inertial effect, non-isothermal flow, taking into account factors such as finite element analysis, the melt thickness direction of the physical quantity changes will no longer be ignored, can be a more comprehensive description of the process of filling flow phenomena, so that results of the analysis more realistic conditions, applicable to all plastic products. Its three-dimensional grid is from the four-node tetrahedron unit. And using the new 3D stereoscopic display technology, can quickly model clearly shows that internal and external flow field, temperature field, stress field and velocity field such as analysis results. For the above-mentioned results of the analysis can also be used such as bit lines or equipotential surface display, so that physical models and external changes in the variables show more clearly the case, Moldfiow also offers animation capabilities, through 3D animation display plastic melt in the changes in the flow cavity, allowing users to more intuitively see the design and manufacturing process may encounter problems. But the 3D technology, meshing demanding, more complex equations to calculate the amount of large, long duration and the computational efficiency is low, not suitable for short development cycle and need to be repeatedly revised by CAE verification injection mold design. Therefore, the current penetration rate of the technology is not very high, but it will eventually replace the surface flow of technology and double-sided streaming technology. 7 Development Trend of Injection Molding Injection Molding CAE technology, whether in theory or in the application have made great strides, but in the following still needs further improvement and development : (1) mathematical models, numerical algorithms to gradually improve the Injection Molding CAE technology, practicality, depending on the accuracy of the mathematical model and numerical algorithm accuracy. The current commercial simulation software models do not fully consider the physical quantities in the thickness direction of the impact of the software in order to further improve the analysis accuracy and scope to further improve the existing mathematical models and algorithms. (2) the whole process of injection molding simulation At present, the injection molding simulation software are mainly filling, flow, packing, cooling, stress and strain and warpage analysis modules, each module was developed based on independent mathematical models, these models has been simplified to a large extent, ignored of the mutual effects. However, in view of injection molding process, plastic melt filling, flow, packing and cooling are intertwined and affect each other and, therefore, filling, flow, packing and cooling analysis module must be organically combined to carry out coupling analysis, in order to comprehensively reflect the real situation of injection molding. (3) optimization theory and algorithms, so that CAE technology active to optimize the design Artificial intelligence technologies, such as expert systems and neural networks on the design calculations, so that simulation