CAPP中箱体类零件信息描述的一种新方法

本文提出了一种C APP中面向箱体类零件的信息描述方法,它通过方位描述、轮廓描述、形面描述等多个处理过程,来满足(A PP对零件信息描述的要求。最后本文介绍了以这种描述方法为依据所开发的交互式零件信息输入系统。     

面向FMS的计算机辅助工艺设计系统

介绍了一种以先进的柔性制造系统ＦＦＳ１５００－２为对象、针对墙板类零件的ＣＡＰＰ系统ＨＺＣＡＰ－ＡＰＴ总体结构，并提出一种描述零件信息的新方法。该系统以人机对话的方式输入零件的几何信息和工艺信息，由计算机自动生成零件的工艺文件和在ＦＦＳ１５００－２上加工的数控程序单。     

A Generative Computer-Aided Process Planning System for Prismatic Components

This paper deals with design and development of a generative computer-aided process planning (CAPP) system for prismatic components and named PSG-CAPP. The proposed CAPP system has been divided into three modules. The first module is concerned with feature extraction. The second and third modules deal with planning the set-up, machine selection, cutting tool selection, cutting parameter selection, and generation of process plan sheet. The whole CAPP system is developed using Visual Basic 6.0 as front end and Oracle 7.3 as back end. The SolidWorks98 plus has been used for modelling, and feature extraction has been implemented using a program written in Visual Basic 6.0. The speciality of the developed CAPP system is that it is linked with the CAD module and it extracts the majority of features automatically prior to process planning. The developed CAPP system has been tested with aerospace components. The main feature of the proposed CAPP system is its ability to handle a variety of prismatic components and generate process plans for them. A case study has been included to highlight the potential of the CAPP system. ID="A1"Correspondance and offprint requests to: Professor P. V. Mohanram, Department of Mechanical Engineering, PSG College of Technology, Peelamedu, Coimbatore 641004, India. E-mail: msadaiah@yahoo.com     

基于CAD平台及其开发工具的箱体类零件CAD／CAPP集成系统开发技术

针对箱体类零件,提出基于ＭＤＴ设计平台和利用ＯｂｊｅｃｔＡＲＸ、ＭＣＡＤＡＰＩ接口技术进行开发ＣＡＤ／ＣＡＰＰ集成系统的关键技术。具体包括ＭＤＴ环境下的零件特征造型,零件特征库的建立,零件特征信息模型的表达,特征识别和信息的提取,在此基础上以人机交互方式深加零件的工艺信息,并实现ＣＡＤ／ＣＡＰＰ系统的集成。     

Rule-based process planning by grouping features

A macro-level CAPP system is proposed to plan the complicated mechanical prismatic parts efficiently. The system creates the efficient machining sequence of the features in a part by analyzing the feature information. Because the planning with the individual features is very complicated, feature groups are formed for effective planning using the nested relations of the features of a part, and special feature groups are determined for sequencing. The process plan is generated based on the sequences of the feature groups and features. When multiple machines are required, efficient machine assignment is performed. A series of heuristic rules are developed to accomplish it.     

Studies on process plan representation in CAPP systems

Process planning establishes the methods and means of converting the raw material into a finished part. The planning function interacts with the manufacturing system through (a) the design specification, (b) manufacturing resources, and (c) the process plan. Similarly, computer aided process planning (CAPP) establishes the links with its application environment through the analogous models. Though much attention is paid to the modelling of the part and manufacturing resources, modelling of the process plan has been an ignored topic to-date. The present paper discusses the need for modelling the process plan, and proposes a framework for process plan internal representation (PPIR) for the effective integration of CAPP and CAM functions. The implementation of the proposed framework in GIFTS — a CAPP system for rotational parts — is also discussed.     

An intelligent process planning system for prismatic parts using STEP features

This paper presents an intelligent process planning system using STEP features (ST-FeatCAPP) for prismatic parts. The system maps a STEP AP224 XML data file, without using a complex feature recognition process, and produces the corresponding machining operations to generate the process plan and corresponding STEP-NC in XML format. It carries out several stages of process planning such as operations selection, tool selection, machining parameters determination, machine tools selection and setup planning. A hybrid approach of most recent techniques (neural networks, fuzzy logic and rule-based) of artificial intelligence is used as the inference engine of the developed system. An object-oriented approach is used in the definition and implementation of the system. An example part is tested and the corresponding process plan is presented to demonstrate and verify the proposed CAPP system. The paper thus suggests a new feature-based intelligent CAPP system for avoiding complex feature recognition and knowledge acquisition problems.     

RDCAPP: A real-time dynamic CAPP system for an FMS

Computer-aided process planning (CAPP) systems need to consider the uncertain nature of the shop-floor prior to the identification of job routes and processing sequences. This paper describes the design and development of a prototype, real-time dynamic CAPP (RDCAPP) system for a multimachining-centre flexible manufacturing system (FMS). Concepts relevant to this research include CAPP, profile input using group technology (GT), artificial-intelligence-based expert systems, and FMSs.RDCAPP considers facility characteristics, machine capacity and the current shop-floor conditions prior to developing a process plan Input to the system is through a GT code and additional auxiliary interactive inputs. RDCAPP uses uncertainty management techniques to keep track of and adapt to changes in shop-floor status. The paper discusses the architecture of RDCAPP in detail. The system was tested rigorously and its outputs validated. Ideas for future research are presented.     

Object-oriented and fuzzy-set-based approach for set-up planning

Set-up planning is not only a key element of computer-aided process planning (CAPP), but also a key factor for the integration of CAPP with computer-aided fixture planning (CAFP) and production planning and scheduling (PPS). In this work, an object-oriented and fuzzy-set-based approach is developed for set-up planning. Object-oriented technology is employed to represent set-up planning knowledge and generate alternative set-ups which can respond to the dynamic manufacturing resource and facilitate the CAPP/PPS integration. Based on fuzzy-set theory, a fuzzy evaluation function is proposed to produce optimal set-ups. Combined with a real project, a set-up planning system is developed to generate alternative and optimal set-up plans for the machining of prismatic parts.     

Development and evaluation of feature-focused dynamic routing policy

This paper reports on a development of feature-focused dynamic routing policy and its evaluation in a flexible manufacturing systems (FMS) simulation framework. The dynamic policy is based on an integrative methodology in which process planning system IMPlanner is integrated with FMS simulation module. IMPlanner’s rule-based system process selection system performs knowledge-intensive task of generating alternative processing options for each feature for parts in production plan. Generated alternative routings (process plan network) for each part are utilized in the FMS simulation module such that routing decision in FMS are made on periodic intervals by considering alternative processes for each feature and making decision based on the current system status and performance. The proposed framework has been evaluated in an experimental FMS simulation module, implemented in Arena, in which two performance criteria, machine utilization and WIP, were used to make routing decisions. The feature-focused approach is compared with traditional static decision-making, and its improved performance is demonstrated.     

On-line integration of a process planning module with production scheduling

An approach to the on-line integration of process planning and production scheduling is reported. Based on a geometric modeller, a geometric analyser and a knowledge base, the process planner generates alternative process plans and provides automatic tool selection and calculation of the appropriate machining parameters. Time and cost estimations are input to the decision-making module in the production scheduling system that produces optimal scheduling decisions as well as a complete record of the actual state of the factory resources. An information flow, designed as a relational data model, maintains the interaction between the process planning and the production scheduling systems and provides the dynamic feedback to the process planner. Specific geometry features of the blank, the finished part and the cutting tools, and geometry features-based rules are stored in the database of a developed CAPP system by using a separate CAD interface. The integrated production planning and production scheduling system and the CAPP system were validated with rotational parts machining.     

集成化CAPP系统的开发

介绍了一个回转体零件创成式CAPP系统NPURCAP,它是一个面向车削加工中心,面向CIMS环境的集成化CAPP系统,初步实现了同CIMS各集成单元的集成。在此基础之上,作者对CAD/CAPP/CAM的集成及CAPP同其它各CIMS环节的集成进行了更深入研究与探索。     

CIMS环境中的集成化工艺过程设计

介绍一个ＣＩＭＳ或ＦＭＳ环境下的集成化ＣＡＰＰ系统－ＴＨＣＡＰＰ，该系统以非回转体零件为加工对象，利用ＩＧＥＳ实现与ＣＡＤ／ＣＡＰＰ／ＣＡＭ的信息集成。工艺路线生成核心是创成式专家系统，推理机的控制策略以启发式搜索的估价函数为主，可自动选择定位夹紧面。工艺知识库为独立的、可维护的形式，根据ＣＩＭＳ车间的实际环境可获得多种工艺方案。     

Batching in flexible manufacturing systems

Batching is necessary in intermittent production, where the facility is designed to process a variety of parts and the set-up costs between dissimilar parts are significant. With multi-mission machineries, automatic tool changers, and a random-access material handling system, a flexible manufacturing system (FMS) can process dissimilar parts concurrently with minimal set-up time/cost. When parts are batched in an FMS, they are scheduled to join different queues before they are introduced to the shop-floor. This paper investigates the problem of batching in an FMS. A linear zero-one integer programming model of the batching problem is presented.     

A modular simulator for design,planning, and control of flexible manufacturing systems

Flexible manufacturing systems are designed to produce a variety of different part types with high machine utilisation, short lead times and little work-in-progress inventory. Simulation is an efficient tool to verify design concepts, to select machinery, to evaluate alternative configurations and to test system control strategies of an FMS. This paper discusses a general-purpose, user-oriented discrete simulator (the Modular FMS Simulator) which can be used for design as well as for operation and scheduling of FMSs. The package can be implemented in different hierarchical steps of FMS production planning. It is also a useful tool in validating the results of analytical models or heuristic procedures developed for FMS problems. This package contains features for the system hardware and the control hierarchy. The model can study multiple part families, various station types, different number of work-in-process buffers and carts and almost any system layout. It is also possible to analyse the performance of the system. The package contains a set of decision rules from which the user can make his choice.     

汽车回转类零件CAPP系统的研究

介绍大批量生产环境下的汽车回转类零件CAPP RPCAP系统的结构、功能及特点 ,重点讨论零件信息输入、工艺规程生成等关键技术问题。该系统可实现工序内容和工序图的自动生成     

Operation element-based efficiency for process plans and designs

In previous work the authors have developed graph-theoretic efficiency measures of process plans for rotational parts. The measures assess the technical efficiency under which a particular design can be manufactured, i.e. its manufacturability. This paper extends the earlier work by incorporating geometric dimensioning and tolerancing and developing a new technique for assessing the manufacturability of any part (prismatic and rotational). The aim is to develop an automated technique for assessing part designs.     

基于特征设计的回转体零件CAD/CAPP集成系统的研究与开发

介绍了所开发的一种基于特征设计的回转体零件 CAD/ CAPP集成系统。系统采用基于特征设计的零件信息模型 ,实现零件的信息共享 ,使 CAPP决策过程可直接应用 CAD输出的信息。在此基础上 ,通过建立基于数据库的工艺决策模型 ,实现了工艺过程的生成和输出     

基于样件工艺定义的CAPP工具化的研究

提出了一种基于样件工艺定义的 CAPP工具化的总体结构。描述了样件工艺模板定义的一般过程。在零件工艺要素化的基础上 ,实现了工艺流程和工序内容的参数化。并利用工艺设计参数化的方法实现具体零件工艺的设计。     

计算机支持协同工作的CAPP系统的研究

针对要提高CAPP系统的协同化和实用化水平,论述了基于CSCW的CAPP系统的实现方法;采用WebService技术对CAPP的结构进行了设计,同时采用XML对CAPP系统核心部分——工艺规程的数据进行了详细描述。最后,给出了基于CSCW的CAPP系统的体系结构,简述了该系统的工作流程。