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1、译文标题注塑成型的智能模具设计工具原文标题Intelligent Mold Design Tool For Plastic Injection Molding作 者Jagannath Yammada, Terrence L. Chambers, Suren N. Dwivedi 译 名加甘纳斯亚玛达，特伦斯 L 钱伯斯和苏伦N德维韦迪国 籍美国原文出处Submitted to ASME/JDSMC Special Issue on Sensors摘要注塑成型是一个生产热塑性塑料制品最流行的制造工艺，而模具设计是这个过程的一个重要方面。模具设计需要专业的知识、技能，最重要的是拥有该领域的经验。三
2、者缺一不可。生产塑料组件需要选择恰当的模具，如果缺乏其中之一，这种选择就得在反复试验的基础上进行。这会增加生产成本，并造成设计上的不一致。本文介绍了智能模具设计工具的发展。该工具捕获模具设计过程的知识，并且以符合逻辑的方式将这些知识反映出来。所获得的知识将是确定性的，但模具设计过程中的信息是非确定的。一旦开发了模具设计工具，它将指导使用者根据不同客户的要求，为其塑料零件选择合适的模具。导言注塑成型工艺过程需要专业的知识、技能，最重要的是需要它成功的实践经验。通常是工艺参数控制过程的效率。在制造过程中，有效地控制和优化这些参数能实现一致性，这种一致性会在零件质量和零件成本上表现出来的问题。1 智
3、能化工程模块注塑成型工艺（IKEM）基于知识的智能化工程模块的注塑成型工艺（IKEM）是一种软件技术，它领先于并行工程和CAD / CAM系统。它集成工程的设计和制造工艺的最新知识，给用户各种设计方面的指示，通过减少在产品开发设计阶段的工程变更，有助于减少一些工时。该系统将用于注塑设计，设计迭代和流程整合。目前的过程由许多手工计算、CAD图形结构和从以前项目取得的经验三部分组成。一旦工程师完成设计，这将是性能评估。该IKEM项目已分为三大模块。 (1) 费用估算模块(2) 模具设计模块(3) 生产模块IKEM系统有两种形式输入。在一个CAD模型的形式（Pro/E文件）下输入，和在给出的用户界面
4、形式下输入。图1-1说明了那种进入每个模块的输入形式和用户输出形式。制造商的经验水平将决定如何有效地控制工艺参数。有时这就导致人为错误引起的不一致性。还有经验不足，时间、资源短缺和创新的空间不大的情况。通过创造所谓的“智能模型”的问题，工程学知识提供了一个可行的方案去解决所有这样用户输出形式成本估计制造模架设计用户输入形式语法分析程序CAD模型图1-1 组织工程的IKEM2 智能模具设计工具在它的基本形式中模具设计工具是一个从文本文件中提取输入的Visual Basic应用程序，这种文本文件包含关于零件和用户输入程序。该文本文件包含来自Pro/E的一个信息文件的零件的几何解析。输入是用来估测模
5、具得尺寸和其它各种特性。2.1 文献回顾模具设计的是另一种注塑成型过程的阶段，有经验的工程师在很大程度上有助于自动化进程，提高其效率。这个问题需要注意的是深入研究设计模具的时间。通常情况下，当设计工程师设计模具时，他们会参阅表格和标准手册，这会消耗大量的时间。另外，在标准的CAD软件中需要大量的时间去考虑模具的建模组件。不同的研究人员已经解决了缩短用不同的方式来设计模具所花费的时间的问题。凯尔奇和詹姆斯采用成组技术来减少模具设计时间。聚合一类注塑成型件的独特的编码系统和在注射模具中所需的工具已开发，它可以适用于其它产品生产线。实施编码系统的软件系统也已经被开发。通过获取在这方面领域的工程师的经
6、验和知识，尝试直接使模具设计过程的自动化。并行模具设计系统的研究开发就是这样的一个过程，在并行工程环境中试图制定一个系统的注塑模具设计流程。他们的研究目标是研制一个有利于并行工程实践的模具开发的进程，和研制开发一个以知识为基础的为注塑模具设计提供工艺问题和产品要求的辅助设计。通过各种方式获取关于模具设计过程的确定信息和不确定信息，研究人员一直试图使模具设计流程自动化。这个研究试图研制开发一个独特的模具设计应用程序，它一确定性和不确定性两种形式获取信息。 2.2 采用的方法为了发展智能模具设计工具，传统的模具设计方法在被研究。应用程序开发人员和设计工程师合作设计一种特定塑料零件的模具。在此期间，
7、被工程师采纳用来选择模底座的方法正在被地密切关注和筛选过程的各个方面，需要他的知识经验来确定。此外，有时候工程师将参考图表和手册以规范其甄选过程。这耗费时间的过程，稍后也被记录在应用程序中。系统的阐述依据输入和输出的应用程序是下一阶段。这涉及到如何定义什么养的模具布局信息是用户最需要的，也是他输入最少却得到相同的输出。根据在模具设计工作中收集到的信息，由工程师遵循的公约被转化为if - then规则。决策表是用来解释各种可能出现的情况，它们是当处理模具设计工程中某一特定的方面所提出的。这样被制定规则，然后被组织在相互交融的模块中，使用应用程序开发环境。最后，应用程序是检验其正确性，当涉及到为塑
8、料零件设计模具在工业生产中。2.3 选择合适的模架通常情况下，为制造塑料零件选择适当的模架所涉及的有：（1）估计模腔数 模腔数量的决定取决于在一定时间内所需部件的数量，像机器的塑化能力，废品率等问题也会影响到模架的模腔数量。（2）确定镶块及其尺寸 镶块有助于模架重用，因此有助于降低生产成本。当涉及到尺寸和数量的选择，作出决定取决于现有的镶块的重用性和新的镶块的成本。（3）确定浇道的尺寸和定位 浇道的尺寸取决于所成型的材料。尽管还有其它要考虑材料特性来决定它的浇道的尺寸供符合它的流量要求。转轮的定位，取决于所用流道的拓扑布局。虽然循环的浇道系统始终是最好的，支道系统的平衡，避免流道均衡补偿的树枝
9、状浇道系统是一个最被广泛应用的系统。（4）确定浇道直径 浇道直径决定于模具的尺寸，模腔的数量或在一定的时间内用来填补的塑料的总数。 （5）浇口的定位 塑料在某一点进入模腔，在这点可以均匀填充满模腔。浇口可以设在循环模腔的任何周围点，但当填补矩形腔时，必须从中部流进。（6）确定供水道的的尺寸和定位 供水道之间和从模具中的任何壁上以标准的距离定位。该公约不是用一个直径范围定位水道在模具壁上。 （7）根据以上结论确定模具的尺寸 根据以上的所有结论，模具的大概尺寸可以被估计，并四舍五入至最接近的产品目录号。在模架以前，如果重新设计，考虑到以上所有方面会降低成本和减少设计时间，进入重新设计。建立问题，需
10、要人的知识和经验，模具设计方面消耗的时间涉及到图表，数据表等，为开发应用程序的问题解释如图2-1所示。虽然大部分的输入如模腔数、腔的图像尺寸、周期时间，都是根据客户要求，其他输入如塑化能力、每分钟注射量等，可从机器的说明书中获得。应用程序的输出包含模具尺寸和其他资料，这显然有助于在目录中选择标准模架。除了输入和输出，图2也显示了产生的最终输出的各种模块。2.5 制定规则在这个阶段，专家的知识可以通过多形式的“如果-那么”语句表现出来。这个规则可以是对定性和定量知识的陈述。所谓定性知识，是指一个能够解决计算问题的确定性的信息。所谓定性，是说对于不确定性的信息，而仅仅是作为在以往个案的基础上的一种
11、已经应用的规则。一个典型的规则说明如下：输入主程序镶块尺寸模腔图像维数冷水道直径周期时间零件重量塑化能力每分钟注射量允许时间模具尺寸浇道尺寸模腔数输出模腔数模具尺寸浇道尺寸浇口尺寸冷水道定位图2-1 模具设计模块的组织如果材料=“缩醛”和分流道长度“0，那么分流道直径 = 0.062 结束 当制定了规则，重要的是我们用一种严谨的方式的来表现这些信息，同时要避免重复、不完整和不一致的现象。决策表可以帮助处理上述问题，它是通过对过于冗余和广泛的问题陈述的检查实现的。比如说，在选择适当的模架的过程中，模架尺寸取决于型腔和镶件的数目。为确保所有型腔和镶件都被考虑到，我们使用了决策表，并随后用决策表来制
12、定规则。表2-1 决策表样本模腔数目（1，2，4）111222444模块数目（1，2，4）124124124模具尺寸A*AB*ABC表2-1显示了在一个以上的情况下，模具的尺寸是相同的情况 A:模具宽度 =(镶块长度 + 2)；模具长度=(镶块长度 + 2)；模具厚度=镶块厚度。情况 B:模具宽度=(2*镶块宽度 + 3.5)；模具长度=(镶块长度+ 2)；模具厚度=镶块厚度。情况 C: 模具宽度=(2*镶块宽度 + 3.5)；模具长度=(镶块长度+ 3)；模具厚度=镶块厚度。型腔的数目是一个，镶件的数目也是一个的情况和型腔数目是两个和四个的情况具有相同的模具尺寸，这三种情况可以归结为一个单一
13、的规则： 如果 镶块的数目= 1，则模具宽度 =（镶块宽度 + 2）模具长度 =（镶块长度+ 2）模具厚度 = 镶块厚度 结束为了方便和清楚起见，用一种标准的编程语言将这些规则模块化。每个模块生成一组输出，这个输出又将是对其他模块的输入。2.6 测试应用通过使用各种测试案例对智能模具设计中的应用程序进行了验证。对于每一个案件的零件信息，模具和机器的信息资料种类繁多，人类专家证实了把这些信息输入到应用程序的结果。表2显示了一个这样的试验，需要两个模腔，也没有镶件的存在。应用程序提供近似的模具尺寸，执行尺寸，浇口尺寸和亚军的模腔长度基于模腔图尺寸和其他信息。表2-2 典型的测试案例显示程序的输入和
14、输出输入镶块数量0镶块长度0镶块宽度0镶块厚度0模腔模样长度模腔模样宽度模腔深度模样冷水道直径零部件生产数量1000时间6循环时间26废品率每分钟注射量材料ABS输出程序输出模腔数2模具长度模具的宽度模具厚度浇道直径浇道长度最大浇口套直径通过使用各种测试案例对智能模具设计中的应用程序进行了验证。对于每一个案件的零件信息，模具和机器的信息资料种类繁多，人类专家证实了把这些信息输入到应用程序的结果。表2显示了一个这样的试验，需要两个模腔，也没有镶件的存在。应用程序提供近似的模具尺寸，执行尺寸，浇口尺寸和亚军的模腔长度基于模腔图尺寸和其他信息。获得的模具尺寸非常接近人类专家的一个典型设计，但并没有明
15、确地说明了一个模具标准件的用途，就像D-M-E模具目录中的一种特定的模具。模具尺寸是基于所用材料而定的，因此它被限制在一定的范围。3总结本文介绍了在发展智能模具设计应用中所采用的方法，这种应用是根据用户输入进行模架选择的。获取知识的过程首先是通过与业内专家密切协商设计一种模架，也通过从旧书和数据表中收集确定性信息。收集到的资料，表示了在不同的模块中规则的排列形式。这些资料可定性和定量地对模具进行选择。决策表是用来减少规则库的规模，使规则库中的问题域全面。在不同的模块中使用这些规则来开发应用程序，当谈到在给业内生产的塑件选择适当的模架时就为应用程序的有效性作测试。参考文献1 钱伯斯 T. L.帕
16、金森 A. R. “知识代表及专家系统的混合转换。” 美国机械工程师学会，1998，120:468-474.2 凯尔其詹姆斯R.“软件升压模具设计效率”的成型系统，1999， 3:16-23. 3 李荣显，陈育民，邹昶,“开发一个并行模具设计系统：以知识为基础的办法”，计算机集成制造系统，1997，4:287-307. 4 斯特德曼萨利佩尔M,“在工程设计专家系统：一种注塑成型的塑料件的应用”智能制造，发动机1995，2:347-353.5 费尔南德斯A，卡斯塔尼J,赛尔 F, “CAD / CAE信息的模具和热塑性塑料注射原型设计的”信息技术1997:117-124. 6 道格拉斯M布莱斯,
17、“塑料注射成型，材料选择和产品设计”1997:1-48.7 道格拉斯M布莱斯，“塑料注射成型模具设计基础”，1997，2:1-120. Session VA4Intelligent Mold Design Tool For Plastic Injection MoldingJagannath Yammada, Terrence L. Chambers, Suren N. DwivediDepartment of Mechanical EngineeringUniversity of Louisiana at LafayetteAbstractPlastic Injection molding
18、is one of the most popular manufacturing processes for making thermoplastic products, and mold design is a key aspect of the process. Design of molds requires knowledge, expertise and most importantly experience in the field. When one of these is lacking, selection of an appropriate mold for manufac
19、turing a plastic component is done on a trial-and-error basis. This increases the cost of production and introduces inconsistencies in the design.This paper describes the development of an intelligent mold design tool. The tool captures knowledge about the mold design process and represents the know
20、ledge in logical fashion. The knowledge acquired will be deterministic and non-deterministic information about the mold design process. Once developed the mold design tool will guide the user in selecting an appropriate mold for his plastic part based on various client specifications.IntroductionThe
21、 plastic injection molding process demands knowledge, expertise and, most important, experience for its successful implementation. Often it is the molding parameters that control the efficiency of the process. Effectively controlling and optimizing these parameters during the manufacturing process c
22、an achieve consistency, which takes the form of part quality and part cost.The level of experience of the manufacturer(s) determines how effectively the process parameters are controlled. This sometimes leads to inconsistency introduced by human error. There is also the case where there is inexperie
23、nce, shortage of time, resources and little scope for innovation. Knowledge-based engineering provides a feasible solution to all these problems by creating what is called an “intelligent model” of the problem.1 IKEMIntelligent Knowledge based Engineering modules for the plastic injection molding pr
24、ocess (IKEM) is a software technology that is a step ahead of the concurrent engineering and CAD/CAM systems. It integrates current knowledge about the design and manufacturing processes and helps to reduce several man-hours by reducing engineering changes in the design phase of product development
25、by giving users instruction about various design aspects. The system will be used for injection molding design, design iterations, and process integration. The current process consists of many manual computations, CAD graphical constructions, and experience attained from previous projects. Once the
26、engineer completes the design, it will be evaluated for performance. The IKEM project has been divided into three major modules.1. The cost estimation module2. The mold design module3. The Manufacturing moduleInput to the IKEM system is of two forms. Input in the form of a CAD model (Pro-E file) and
27、 input given at the User Interface form. Figure 1 illustrates the kind of input that goes into each module and the output given to the user. Figure 1. Organization of the IKEM Project2 Intelligent Mold Design ToolThe mold design tool in its basic form is a Visual Basic application taking input from
28、a text file that contains information about the part and a User Input form. The text file contains information about the part geometry parsed from a Pro/E information file. The input is used to estimate the dimensions of mold and various other features.2.1 Literature Review Design of molds is anothe
29、r stage of the injection molding process where the experience of an engineer largely helps automate the process and increase its efficiency. The issue that needs attention is the time that goes into designing the molds. Often, design engineers refer to tables and standard handbooks while designing a
30、 mold, which consumes lot of time. Also, a great deal of time goes into modeling components of the mold in standard CAD software. Different researchers have dealt with the issue of reducing the time it takes to design the mold in different ways. Koelsch and James have employed group technology techn
31、iques to reduce the mold design time. A unique coding system that groups a class of injection molded parts, and the tooling required ininjection molding is developed which is general and can be applied to other product lines. A software system to implement the coding system has also been developed.
32、Attempts were also directed towards the automation of the mold design process by capturing experience and knowledge of engineers in the field. The development of a concurrent mold design system is one such approach that attempts to develop a systematic methodology for injection mold design processes
33、 in a concurrent engineering environment. The objective of their research was to develop a mold development process that facilitates concurrent engineering-based practice, and to develop a knowledge-based design aid for injection molding mold design that accommodates manufacturability concerns, as w
34、ell as product requirements.Researchers have been trying to automate the mold design process either by capturing only the deterministic information on the mold design process or the non-deterministic information, in various ways. This research uniquely attempts to develop a mold design application t
35、hat captures information in both forms; deterministic and non-deterministic.2.2 Approach AdoptedIn order to develop an intelligent mold design tool, the conventional method of designing molds is studied. The application developer and the design engineer work together in designing a mold for a partic
36、ular plastic part. During this time, the approach adopted by the engineer to select the mold base is closely observed and aspects of the selection process that require his knowledge/experience are identified. Also, there will be times when the engineer will refer to tables and handbooks in order to
37、standardize his selection process. This time consuming process is also recorded to incorporate it later in the application.Formulating the problem for the application in terms of inputs and outputs is the next stage. This involves defining what information about the mold layout is most required for
38、the user and also the minimum number of inputs that can be taken from him to give those outputs.Based on the information gathered in the mold design exercise, the conventions followed by the engineer are transformed into if-then rules. Decision tables are used to account for all possible cases that
39、arise when dealing with a particular aspect of the mold design process. The rules so framed are then organized into modules interacting with each other, using an application development environment. Finally the application is tested for its validity when it comes to designing molds for plastic parts
40、 manufactured in the industry.2.3 Selection of Appropriate Mold Base Typically, selection of appropriate mold base for manufacturing a plastic part involvesEstimating the number of cavities The number of cavities is decided depending on the number of parts required within a given time. There are als
41、o other issues like the plasticizing capacity of the machine, reject rate etc that affect the number of cavities to be present in the mold base.Deciding on the presence of inserts and their dimensionsInserts facilitate the reusability of the mold base and therefore help in reducing cost of manufactu
42、ring. When it comes to selecting the dimensions and the number, a decision is made depending on the reusability of existing old inserts and cost of ordering new ones.Determining the size and location of runnersThe runner size depends on the material being molded. Although there are other considerati
43、ons material properties determines the channel size required for its flow. Location of runners mainly depends on the topology of runners being used. Though a circular runner system is always preferable, the branched runner system that avoids runner balancing is the one most widely used.Determining t
44、he diameter of sprueThe diameter of the sprue is decided based on the size of the mold, number of cavities, or the amount of plastic that is to be filled within a given time.Locating gatesPlastic enters the cavity at a point where it can uniformly fill the cavity. A gate can be located at any point
45、on the perimeter of a circular cavity but has to enter at the midsection when it comes to filling rectangular cavities.Determining the size and location of water lines Water lines are located at standard distances form each other and from any wall in the mold. The convention is not to locate a water
46、line within one diameter range on the mold wall.Deciding mold dimensions based on above conclusionsBased on all the above decisions the approximate mold dimensions can be estimated and rounded off to the nearest catalog number. Considering all the above aspects before even modeling the mold base red
47、uces the cost and time that go into redesigning.2.4 Formulation of the ProblemBased on issues that require human knowledge/experience, and aspects of mold designthat consume time referring to tables, data sheets etc., the problem for developing theapplication is defined as shown in Figure 2.Figure 2
48、. Organization of the Mold Design Module.While most of the input, like the number of cavities, cavity image dimensions, cycle time are based on the client specifications, other input like the plasticizing capacity, shots per minute etc., can be obtained from the machine specifications. The output of the application contains mo