Development of a collaborative CAD/CAM system

This paper presents the development of a collaborative CAD/CAM system (COCADCAM). COCADCAM extends an existing single-location CAD/CAM system to a multi-location CAD/CAM application so that two geographically dispersed CAD/CAM users can work together on a three-dimensional CAD-geometry coediting and CAD-related tasks collaboratively and dynamically. COCADCAM dynamically supports CAD data communication that are not available in traditional single-location CAD/CAM. The dynamic data communication is achieved through the development of networking algorithms and CAD/CAM functions in this paper. The networking algorithms based on UNIX Interprocess Communication (IPC), the Network File System (NFS), and a connection-oriented client and server model under the Transmission Control Protocol/Internet Protocol (TCP/IP) suite. The CAD/CAM functions included surface modelling, simulation of a milling toolpath, and post-processing of an NC program following collaborative CAD-geometry coediting, which are directly or indirectly supported by the Application Programming Interface (API) of the CAD/CAM software. The networking algorithms and CAD/CAM functions together can facilitate an environment for CAD-geometry coediting and related tasks such as design, analysis and manufacture. COCADCAM has been successfully implemented through local area network (LAN) and the Internet; a remote machining cell is also linked so that the generated NC program based on a coedited free-form surface can be used for the physical machining operation. The algorithm proposed by COCADCAM can be referenced for the extension of other single-location CAD/CAM systems to multi-location applications.     

一个基于知识的二维模具CAPP／CAM系统MEKCAM

ＣＡＤ／ＣＡＰＰ／ＣＡＭ系统的一体化是计算机智能制造管理系统和计算机集成制造系统等的核心部分和重要研究课题，本文论述一个基于知识的柔性电路板模具ＣＡＰＰ／ＣＡＭ系统－ＭＥＫＣＡＭ。首先讨论ＭＥＫＣＡＭ的结构及功能，然后介绍该系统所使用的有关知识和算法，最后，我们给出ＭＥＫＣＡＭ的实现方法及系统评价。     

针对产品的CAD／CAM一体化技术

本文系统地介绍了一种基于ＣＡＤ工作站，利用Ｉ－ＤＥＡＳ软件实现的针对壳体类零件的ＣＡＤ／ＣＡＭ一体化技术。论述了利用ＰＥＡＲＬ数据库实现的从ＣＡＤ模型到ＣＡＰＰ之间信息的传输，分析了在ＣＡＤ与ＣＡＭ集成中创成式ＣＡＰＰ所起的关键作用，并介绍了利用ＧＮＣ图形辅助数控软件对加工过程的仿真以及机床文件的准备，最后系统能生成正确的数控指令。系统初步实现了ＣＡＤ／ＣＡＭ一体化。     

CM,RE和CAD/CAM系统集成环境的研究

对三坐标测量系统、联系实际向工程、CAD/CAM系统信息集成中存在的问题进行分析，提出了面向快速逆向设计和制造集成环境的功能模型、关键技术和处理方法。通过建立CM，RE，CAD/CAM系统的集成平台，对样件、模型进行快速测量，并对测量数据进行数据处理、特征重建、几何造型和数控加工处理，以实现对产品样件或模型的快速逆向设计与制造。     

基于UG的五轴数控机床加工仿真

目前多数五轴数控机床仿真系统,一般只提供二维的动画仿真,而且仿真系统的几何造型功能十分有限,零件和机床模型需要在其他CAD软件中进行建模,然后导人数控仿真系统。由于文件格式的转化,零件的CAD模型将会产生误差,降低了仿真精度。该文利用UGCAD／CAM软件造型功能建立五轴数控机床和零件模型,读取数控代码对机床各部件进行三维运动仿真,并对加工过程中机床运动部件之间的干涉及工件过切进行检查,建立干涉实体,为刀具轨迹的修改提供依据,同时免除了文件格式的转化产生的误差。     

Development of a feature-based and object-oriented concurrent engineering system

Product information modeling is critical to the integration of mechanical CAD/CAM systems and to the implementation of a concurrent engineering system. This paper presents a recent development of a feature-based and object-oriented concurrent engineering system with its focus on a product information modeling technique implemented in the system. The technique was developed to capture product definition data including form features and their spatial relationships and to store them as an object-oriented information model during the design process. The paper also describes the implementation of the information modeling technique and its application to manufacturing process planning in an object-oriented environment.     

Neural networks for estimating the tool path length in concurrent engineering applications

This paper deals with the development of a neural computing system that can predict the cutting tool path length for milling an arbitrary pocket defined within the domain of a product design, in a computer numerically controlled (CNC) setting. Existing computer aided design and manufacturing systems (CAD/CAM) consume significant amounts of time in terms of data entry pertaining to the geometries and subsequent modifications to them. In the concurrent engineering environment, where even the designer needs information from the CAD/CAM systems, such time-consuming processes can be expensive. To alleviate this problem, a neural network system can be used to estimate machining time by predicting cost-dependent variables such as tool path length for the pocket milling operation. Pockets are characterized and classified into various groups. A randomized design is described so that the training samples that have been chosen represent the domain evenly. An appropriate network was built and trained with the sample pocket geometries. The analysis of the performance of the system in terms of tool path length prediction for new pocket geometries is presented.     

一个面向CAD／CAM的演绎数据库管理系统

演绎数据库管理系统ＤＥＤＢＭＳ是工程数据库管理系统ＥＤＢＭＳ／２中的一个子系统。本文着重介绍其产生式语言用户界面、工作流程及功能特点。ＤＥＤＢＭＳ系统的开发，使ＥＤＢＭＳ／２不仅具有工程数据据管理功能，而且具有数据演绎和知识处理能力，从而成为ＣＡＤ／ＣＡＭ系统集成化和智能化的有力支撑工具。     

TiGEMS二次开发接口的设计与实现

分析了CAD/CAM软件二次开发平台的基本设计理论和设计原则。针对典型的商业三维几何造型系统——TiGEMS提出了采用动态链接库技术的二次开发接口设计方法和实现过程。解决了TiGEMS二次开发接口的难点和问题。     

Automation in the design of EDM electrodes

Plastic parts, especially those designed for consumer electronics products, are becoming more compact and freeform in shape. This requires the construction of compact and delicate geometric features in the injection moulds that produce these parts. It is now common practice to employ electric discharge machining (EDM) whenever the conventional machining process fails to machine such delicate features. Although CAD/CAM systems are widely used in mould design and manufacturing, and specific commercial CAD/CAM systems that are customized for injection mould applications are also available, there are still no intelligent CAD tools that address the specific requirements of EDM electrode design. The aim of this research is to develop an intelligent CAD tool that supports EDM electrode design. This CAD tool uses a new technique that recursively splits the EDM region into sub-regions until machinable electrodes can be constructed. The CAD tool has been implemented and integrated into a commercial CAD/CAM system, and 40 different real designs has been used to test its capability in handling a wide variety of geometric shapes. Performance data show that the efficiency of the design process can be improved by at least 50%, with a potential to achieve 85% through improved implementation and further research.     

Computer-aided manufacture

The role and history of CAD in the mechanical engineering industry are briefly discussed.Dominant among recent developments have been the sharp increase in the cost-effectiveness of CAD and CAM systems and the imperatives imposed by the economic climate. Combined with the increasing availability of mature software, these have led to a very rapid proliferation even among small and medium-sized companies, despite the economic recession.Social and competitive pressures are leading to more user-friendly system?. The greatest progress is expected in geometric modelling, in the application of knowledge engineering technologies and in advanced database systems, permitting the closer integration of CAD and CAM activities.     

An integrated implementation for product design

This paper represent an integrated implementation to shorten the product development cycle. The developed system uses machine vision techniques to automate the creation of CAD models for existing parts of prototypes. It extracts the manufacturing features based on the created CAD database and the tolerances that are to be added to the created CAD dabatase for CAD/CAM practice and concurrent analysis. The geometric features are organized in a database which can be imported to an automated process planning and cost estimation system. This integrated implementation is capable of providing manufacturing feedback during the product development stage. This paper outlines the development of the vision system, the creation of the CAD model, and the design of the database.     

JPernLite: extensible transaction services for the WWW

Concurrency control is one of the key problems in design and implementation of collaborative systems such as hypertext/hypermedia systems, CAD/CAM systems, and software development environments. Most existing systems store data in specialized databases with built-in concurrency control policies, usually implemented via locking. It is desirable to construct such collaborative systems on top of the World Wide Web, but most Web servers do not support even conventional transactions, let alone distributed (multi-Website) transactions or flexible concurrency control mechanisms oriented toward team work-such as event notification, shared locks, and fine granularity locks. We present a transaction server that operates independently of Web servers or the collaborative systems, to fill the concurrency control gap. By default, the transaction server enforces the conventional atomic transaction model, where sets of operations are performed in an all-or-nothing fashion and isolated from concurrent users. The server can be tailored dynamically to apply more sophisticated concurrency control policies appropriate for collaboration. The transaction server also supports applications employing information resources other than Web servers, such as legacy databases, CORBA objects, and other hypermedia systems. Our implementation permits a wide range of system architecture styles     

CAD/CAM 外部数据库系统的研究与应用

CAD/CAM 软件的二次开发越来越受人们的重视,而建立自己的数据库与 CAD/CAM 软件集成是重中之重。本 文在著名的 CAD/CAM 软件 PRO/E 的基础上,结合 VC.NET,用 ADO 技术对外部数据库的连接方法进行了研究,并根 据实际需求建立了一套属于自己的刀具数据库系统。     

STEP信息集成软件工具的设计和实现

ＳＴＥＰ是国际标准化组织ＩＳＯ正在组织开发的应用于计算机集成制造系统（ＣＩＭＳ）信息集成的产品数据表达与交换标准，ＳＴＥＰ不仅是一种规范，更是一种信息集成技术，本文以ＣＡＤ／ＣＡＰＰ／ＣＡＭ系统集成为背景，提出了ＳＴＥＰ信息集成支持工具ＥｘＴｒａ的设计和实现技术，该软件工具已成功且有效地应用于ＣＡＤ／ＣＡＰＰ／ＣＡＭ系统集成中。     

A PDES/STEP-based model and system for concurrent integrated design and assembly planning

Product data exchange and interfacing between different CAD/CAM systems are of great importance to the development of concurrent integrated design environments and computer integrated manufacturing systems. This paper presents a STEP-based method and system for concurrent integrated design and assembly planning. An integrated object model for mechanical systems and assemblies is first defined by a hierarchy of structure, geometry and feature. The structure is represented as a component-connector or joint multi-level graph with both hierarchical functional and assembly relations. These hierarchical relation models are then used for uniformly describing their causal relations both for assembly level and feature based single part level. The generic product assembly model is organized according to STEP, using mostly the entities of integrated resources and partly self-defined entities, which are necessary for design and assembly planning. Based on the generic product assembly model, STEP-based strategies and agent concepts are used for agent-based concurrent integration of design and assembly planning. A prototype system, consisting of a CAD system, a product modeling system, an assembly planning system, and an assembly evaluation system is developed, in which product data can be exchanged between these subsystems. Details about the implementation of the system are addressed. The integrated design and assembly planning system can support the introduction of a new product. The results of assembly planning are feedback to the stage of assembly design to improve on the design. A case study is carried out for assembly-oriented design of a gearbox, to illustrate the proposed approach and to validate the developed system.     

Development of CAM system based on industrial robotic servo controller without using robot language

This paper describes the development of a robotic CAM system for an articulated industrial robot RV1A from the view point of robotic servo controller. It is defined here that the CAM system includes an important function which allows an industrial robot to move along cutter location data (CL data) consisting of position and orientation components. In addition, the developed CAM system has a high applicability to other industrial robots whose servo systems are technically opened to end-users. The developed robotic CAM system works as a straightforward interface between a general CAD/CAM and an industrial robot. At the present stage, the relationship between CAD/CAM and industrial robots is not well established compared to NC machine tools that are widely spread in manufacturing industries. The CAM systems for NC machine tools are already established, however, the CAM system for industrial robots has not been sufficiently considered and developed yet. A teaching pendant is generally used to obtain position and orientation data of the arm tip before an industrial robot works. Here, in order to enhance the relationship between a conventional CAD/CAM system and an industrial robot, a simple and straightforward CAM system without using any robot language is developed and implemented. The basic design of the robotic CAM system and the experimental results are presented in this paper.     

基于G代码的工业机器人的自动编程

随着自动化程度的提高和CAD/CAM技术的发展，工业机器人常见的手工示教编程 已经不能满足需要，利用CAD/CAM软件实现机器人自动编程是工业机器人发展的必然趋势． 本文分析了利用通用G代码实现机器人自动编程的可行性，在考虑了数控机床与机器人坐标 系统的差异的基础上，具体研究了G代码程序到机器人工作程序的转换算法，并从编程的角 度，对轨迹仿真、差错检验以及动态优化进行了讨论．     

Systems for unified life-cycle mechanical engineering design: Shared-Tool architectures versus distributed tool architectures

A unified life-cycle engineering design (ULCED) system embodying conceptual design, detailed design, redesign, design for manufacturing, and design maintainability forms the basis of a new computer-based design discipline for improving the overall quality of manufactured goods. The objective of such a system is to review, evaluate, and analyze the entire life cycle of a product and to incorporate, in an integrated fashion, life-cycle knowledge within the design process. Individual CAD/CAM/CAE software, developed under various programming environments and operating systems, and on various types of computer hardware, have met with only limited success in achieving total computational integration. At the initial stages of development of such a system exploration of both technologically and economically feasible architectures is of critical importance.Two ULCED system architectures, broadly classified as shared-tool and distributed-tool, are described and compared on the basis of current computer hardware, available commercial software and data bases, and existing computer programming environments. Important evaluation issues to be considered include implementation costs and complexity and the feasibility of system creation.     

探讨模具CAD/CAM软件开发

模具CAD/CAM是在CAD和CAM独立发展的基础之上,在模具生产当中使用计算机技术,让模具的生产有了一个飞跃。阐述了此种技术的发展情况、软件的特性、软件所具有的优势,探讨了在模具的生产中使用CAD/CAM的原因。通过分析当前CAD/CAM的开发情况及具体的应用,指出了在实际开发中所存在的问题。