基于步长优化的扫略自由曲面加工效率的研究

提出了一种提高扫略曲面三坐标加工速度的优化方法;在曲面加工中,经常使用比较昂贵的商业CAD/CAM软件来生成加工程序,对刀具位置和路径规划进行大量的计算;由于这些商业软件都基于一种比较可靠的算法,所以在功能上都具有相似的功能和效率;也就是说,现在使用的大多数的CAD/CAM系统,都是基于零件的几何特征来加工的;文中提出了主要集中在提出一种基于被加工零件精度自由曲面刀具路径生成方法,推导出前进步距函数,在给定加工误差和没有损失加工精度的情况下,计算出最大的CC(刀具接触点)点间的距离,来减少生成的CC点,减少加工时间,提高了加工效率。     

产品柔性设计系统中知识／信息库的建立

支持动态建模的产品柔性设计系统，能使用户在可视化并行环境下动态完成产品设计中从方案构思到全局产品设计的全部过程。本文介绍了作为该系统核心的设计知识／信息库建立的方法，即采取面向对象的方法来实现知识表示、知识获取及知识／信息库的管理，从而使得该系统具有继承特性及学习功能，不断提高它在产品设计中的作用。     

Computer aids to the design of integrated manufacturing systems

Building an Integrated Manufacturing System is a complicated and expensive task. There are very few companies anywhere that will deliver turn-key CAD/CAM systems, far less produce a full line of hardware and software products covering every function required. In designing such a system we are faced with the problem of the proper interfacing and coordination of several hundreds of functional sub-systems. It is, therefore, a natural endeavour to use CAD methods in the design of CAD/CAM systems. Brief outlines are given of a highly interactive system having formalized diagrams and alphanumeric information on the input side, and readable system documentation and analysis reports, on the output side - both interacting to widely accepted extant techniques. The structure of a more complex system affording further facilities is also presented.     

工程数据库在CASIS-Ⅱ上的实现

本文叙述了造船工程数据库CASIS-DB在"计算机辅助造船集成系统第二期工程CASIS-II"上的实现方法.作为CASIS-II的支撑平台的重要支柱,CASIS-DB提供了计算机辅助造船的数据管理环境,并通过友好的用户接口支持船舶总体设计、船体结构设计和船舶机电设计过程中的数据访问.     

机械产品并发设计原理与方法的探讨

一、前言 为使计算机在机械设计应用中充分发挥作用,创造出一种能模拟人类专家群对杂产品设计问题进行并行处理、相互合作这一自然属性的软件环境是+分重要的。并发设计Concurrent Design),作为     

The role of interfaces,product models and data formats for the integrated use of CAD and for the integration of CAD/CAM

A reference model is presented, which describes the global functionality of a CAD system in a manufacturing environment. The different interfaces in such a model, their functionality and their contribution to the integration of CAD in a given environment are presented as well. Some standards (existing or under development) to be located in such a framework (e.g. IEEE 488 Bus, PDV Bus, ETHERNET Bus, GKS, VDM, VDI, IGES, etc.) are addressed, and the role of product models and dialogue programming based on dialogue cells is discussed in detail.     

Rules for an expert fixturing system on a CAD screen using flexible fixtures

The object of this research is to develop rules for an expert system which will aid in the automatic layout of flexible fixture models on a CAD/CAM system for given applications through an interactive process. The rules are developed and implemented in PROLOG adopting the general sets of fixturing coordinates developed based on the 321-clamping concept and the geometric information such as shape and size of the workpiece to be fixtured. Surface milling is used to demonstrate the principle of the rules and applied to regular polyhedral shapes. Input to the program consists of parameters describing the workpiece to be fixtured which will initiate a search through the databases of rules and fixturing coordinates. Appropriate fixturing rules will be matched and fired to create a datafile containing fixturing points in cartesian coordinates and the list of modular fixture components to be used as an input source to the CAD system.     

分布式协同设计技术综述

分析了分布式协同设计中的关键技术问题,介绍了其目前的主要研究进展和代表性成果．在集成技术方面,重点阐述了CAX／DFX工具的分布集成问题,包括封装、互操作、本体论;在协同技术方面,集中分析了异步协同设计、同步协同设计和协同装配设计;最后对该领域需要解决的深层次问题进行了讨论。     

Knowledge acquisition techniques for feature recognition in CAD models

Automatic Feature Recognition (AFR) techniques are an important tool for achieving a true integration of design and manufacturing stages during the product development. In particular, AFR systems offer capabilities for recognising high-level geometrical entities, features, in Computer-Aided Design (CAD) models. However, the recognition performances of most of the existing AFR systems are limited to the requirements of specific applications. This paper presents automatic knowledge acquisition techniques to support the development of AFR systems that could be deployed in different application domains. In particular, a method to generate automatically feature recognition rules is proposed. These rules are formed by applying an inductive learning algorithm on training data consisting of feature examples. In addition, a technique for defining automatically feature hints from such rule sets is described. The knowledge acquisition techniques presented in this study are implemented within a prototype feature recognition system and its capabilities are verified on two benchmarking parts.     

串口通信在CAD/CAM系统中的设计与实现

串行口通信是终端与计算机或计算机之间进行数据通信的一种方式，在工业上发挥着重要的作用。具有传输距离远、传输稳定、简单实用等特点。论述了在三维造型软件平台上(JHSolid)的CAM模块中串口通讯的实现。应用VisuaI C 结合CSem aJPort类实现自动侦测串口、在数控机床与PC之间进行数据及文件的传输等功能，并讨论该系统的基本原理和具体实现。     

Design of a STEP compliant system for turning operations

The changing economic climate has made global manufacturing a growing necessity over the last decade, forcing companies from East and West to collaborate beyond geographic boundaries in the design, manufacture and assembly of products. The ISO 10303 and ISO 14649 Standards (STEP and STEP-NC) have been developed to introduce interoperability into manufacturing enterprises so as to meet the challenges of responding to production on demand. This paper describes and illustrates a STEP compliant CAD/CAPP/CAM System for the manufacture of rotational parts on CNC turning centers. The information models to support the proposed system together with the data models defined in the ISO 14649 standard used to create the NC programs are also described. A structured view of a STEP compliant CAD/CAPP/CAM system framework supporting the next generation of intelligent CNC controllers for turn/mill component manufacture is provided. Finally a proposed computational environment for a STEP-NC compliant system for turning operations (SCSTO) is described. SCSTO is the experimental aspect of the research and is supported by information models that and have been constructed using a structured methodology and object-oriented methods. SCSTO was developed to generate a Part 21 file based on machining features to support the interactive generation of process plans utilizing feature extraction. A case study component has been developed to prove the concept of using the milling and turning parts of ISO 14649 to provide a turn-mill CAD/CAPP/CAM environment.     

高强混凝土专家系统（HSES）的设计与实现

本文分析了高强混凝土专家系统的设计与实现,主要讨论了高强强混凝土 结构、知识表示、知识库的组织和推理策略以及主要的实现技术。     

Computer aided design of form rolls for NC manufacture

Computer aided design (CAD) and computer aided manufacture (CAM) are two modern areas of computer application which have decisive influence in the manufacturing industries. The recognition of the potential of CAD/CAM is worldwide and many have taken advantage of the new technology. The design and manufacture of form rolls and the special tooling used in cold roll forming of thin walled metal sections are areas where the CAD/CAM approach can make a positive computer aided tool for creating form roll designs suitable for NC (numerical control) manufacturing. This work was undertaken by the Department of Production Technology and Production Management at the University of Aston in Birmingham in collaboration with a leading manufacturer of thin walled sections. Significant improvement of lead time and productivity in both design and manufacturing of form rolls have been accompanied.     

Advanced production systems (APS) — CAD/CAM systems of the future

The CAD/CAM-area is one of the fastest expanding areas in industry of today. In order to support user- as well as vendor-industry, a Norwegian-German project has been started in the field. It consists of a short term project (1982–1984) and a long term project (1982–1991). The paper deals with the results of the cooperative project (APS).     

生命信息专家诊断系统的设计与实现

本文详细讨论了生命信息专家诊断系统的设计与实现方法,介绍了系统的总体结构、各模块的功能、特点以及具体的实现方案。     

Selection of an optimal set of cutting-tool sizes for 21/2D pocket machining

The availability of high speed automatic tool change mechanisms in modem CNC machining centers is making it practical to consider the use of multiple cutting-tool (specifically, flat end-mill) sizes to reduce the total time for machining a 21/2D) pocket. However, current CAD/CAM systems do not support pocket machining using multiple cutting-tool sizes. In this paper, we describe a two-phase methodology for selecting an optimal set of cutting-tool sizes to machine a 21/2D pocket. In the first phase, we employ a new concept called the Voronoi mountain in order to calculate the material volume that can be removed by a specific cutting-tool size, the material volume that will subsequently remain to be machined, and the cutter-paths (and corresponding processing times) for each cutting-tool. In the second phase, we apply a dynamic programming approach for optimal selection of cutting-tool sizes on the basis of the processing time. Our computational experiments indicate that substantial savings in processing time can be achieved by using multiple cutting-tool sizes to machine 21/2D pockets.     

An integrated system for computer aided design and analysis of multibody systems

An integrated system for design and analysis of multibody systems has been developed and is described in this paper. The use of the system is demonstrated through the example provided. The system consists of a commercially available CAD program and a multibody system analysis code developed at the Royal Institute of Technology in Stockholm, These tools are integrated using a relational database, the structure of which was developed at Luleå University of Technology, in order to get a complete system for design and analysis of multibody systems. The main gains from the integrated system are the possibilities of using calculated component data like mass and moment of inertia from the CAD program in the simulation models, the automatic formulation of input files for the analysis code, and finally the visualization of simulation results using the surface data of the solid models. The interactive structured query language (ISQL) of the database management system provides the possibility of examining the components of the multibody system during the design work and before any simulation is performed.     

FPGA-based hardware CNC interpolator of Bezier,splines, B-splines and NURBS curves for industrial applications

Tool path interpolation is an important part of Computerized Numerical Control (CNC) systems because it is related to the machining accuracy, tool-motion smoothness and overall efficiency. The use of parametric curves to generate tool-motion trajectories on a workpiece for high accuracy machining has become a standard data format that is used for CAD/CAM (Computer Aided Design/Computer Aided Manufacturing) and CNC systems. Splines, Bezier, B-splines, and NURBS (Non-Uniform Rational B-splines) curves are the common parametric technique used for tool path design. However, the reported works bring out the high computational load required for this type of interpolation, and then at best only one interpolation algorithm is implemented. The contribution of this paper is the development of a hardware processing unit based on Field Programmable Gate Arrays (FPGA) for industrial CNC machines, which is capable of implementing the four main interpolation techniques. It allows the selection of the required interpolation technique according the application. Two CAD models are designed for test the CNC interpolations; experimental results show the efficiency of the proposed methodology.     

Feature extraction and feature based design approaches in the development of design interface for process planning

The quest for completely automated process planning systems has exposed the lack of techniques capable of automatically understanding the stored CAD models in a manner suitable for process planning. Most current generations of process planning systems have used the ability of humans to translate the part drawing requirements into a form suitable for computer aided process planing. Recently, research advances have been made to improve the understanding of computer stored 3-D part models. The two approaches used are feature recognition and feature based design. This paper presents a state of the art review of feature recognition techniques developed and presents feature based design as an alternative. Process planning systems developed using both approaches are presented.