注塑模外文翻译
注塑成型智能模具设计工具
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形式下输入。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入形式模架设计制造用户输出形式语法分析程 CAD 模型成本估计
2 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，它以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，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。
2.4 问题的提出
建立问题，需要人的知识和经验，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。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。
Intelligent Mold Design Tool For Plastic Injection Molding Abstract
Plastic Injection molding is one of the most popular manufacturing processes for making thermo plastic 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 manufacturing 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 know ledge about the mold design process and represents the knowledge 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.
Introduction
The 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 can achieve consistency which takes the form of part quality and part cost. The level of experience of the manufacturers 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 inexperience 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 IKEM
Intelligent Knowledge based Engineering modules for the plastic injection molding process 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 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 engineer completes the design it will be evaluated for performance. The IKEM project has been divided into three major modules.
1. The cost estimation module
2. The mold design module
3. The Manufacturing module
Input to the IKEM system is of two forms. Input in the form of a CAD model Pro-E file and input given at the User Interface form. The manufacturer's level of experience will determine how to effectively control the process parameters. Sometimes this leads to inconsistency caused by human error. There is lack of experience, lack of time, lack of resources and innovative space. Through the creation of a "smart" model, engineering knowledge provides a feasible scheme to solve all user input form mold design and manufacture of the user output form of syntax analysis process CAD model cost estimation
2 Intelligent Mold Design Tool
The mold design tool in its basic form is a Visual Basic application taking input from a textfile
that contains information about the part and a User Input form. The text file containsinformation about the part geometry parsed from a Pro/E information file. The input is used toestimate the dimensions of mold and various other features.
2.1 Literature Review
Design of molds is another stage of the injection molding process where the experience of an engineer largely helps automate the process and increase its efficiency. The issue that needs attention is the time that goes into designing the molds. Often, design engineers refer to tables and standard handbooks while designing a mold, which consumes lot of time. Also, a great deal of time goes into modeling components of the mold in standard CAD software. Different researchers have dealt with the issue of reducing the time it takes to design the mold in different ways. Koelsch and James have employed group technology techniques to reduce the mold design time. A unique coding system that groups a class of injection molded parts, and the tooling required in injection molding is developed which is general and can be applied toother product lines.
A software system to implement the coding system has also been developed. Attempts
were also directed towards the automation of the mold design process by capturing experience and knowledge of engineers in the field. The development of a concurrent mold design system is one such approach that attempts to develop a systematic methodology for injection mold design processes in a concurrent engineering environment. The objective of their research was to develop a mold development process that facilitates concurrent
engineering-based practice, and to develop a knowledge-based design aid for injection molding mold design that accommodates manufacturability concerns, as well 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 that captures information in both forms; deterministic and non-deterministic.
2.2 Approach Adopted
In 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 particular 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 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 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 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 manufactured in the industry.
2.3 Selection of Appropriate Mold Base
Typically, selection of appropriate mold base for manufacturing a plastic part involves
Estimating the number of cavities
The number of cavities is decided depending on the number of parts required within a given time. There are also 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 dimensions
Inserts facilitate the reusability of the mold base and therefore help in reducing cost of manufacturing. 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 runners
The runner size depends on the material being molded. Although there are other considerations 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 the diameter of sprue
The 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 gates
Plastic enters the cavity at a point where it can uniformly fill the cavity. A gate can be located at any point 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 waterline within one diameter range on the mold wall.
Deciding mold dimensions based on above conclusions
Based 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 reduces the cost and time that go into redesigning.
2.4 Formulation of the Problem
Based on issues that require human knowledge/experience, and aspects of mold designthat consume time referring to tables, data sheets etc.. While most of the input, like the number of cavities, cavity image dimensions, cycle time are based on the client specifications, other input like the plasticizing capacity, shots per minute etc., can be obtained from the machine specifications. The output of the application contains mold dimensions and other information, which clearly helps in selecting the standard mold base from catalogs.