Automated extraction of dimensional inspection features from part computer-aided design models

Metrological inspection planning is among the least explored computer-aided process planning (CAPP) domains. This paper examines the basic issues involved in automated dimensional inspection planning that works within an environment of a generic CAPP support system. A new algorithmic approach based on multi-attributed spatial graphs is developed for extracting inspection features. The features of specific interest to the planner are selected by applying a sequential filtering method. The method is capable of extracting many common types of inspection features (polyhedral, cylindrical and free-form) found in industrial practice.     

Optimization of machining datum selection and machining tolerance allocation with genetic algorithms

In machining process planning, selection of machining datum and allocation of machining tolerances are crucial as they directly affect the part quality and machining efficiency. This study explores the feasibility to build a mathematical model for computer aided process planning (CAPP) to find the optimal machining datum set and machining tolerances simultaneously for rotational parts. Tolerance chart and an efficient dimension chain tracing method are utilized to establish the relationship between machining datums and tolerances. A mixed-discrete nonlinear optimization model is formulated with the manufacturing cost as the objective function and blueprint tolerances and machine tool capabilities as constraints. A directed random search method, genetic algorithm (GA), is used to find optimum solutions. The computational results indicate that the proposed methodology is capable and robust in finding the optimal machining datum set and tolerances. The proposed model and solution procedure can be used as a building block for computer automated process planning.     

A CAPP framework with optimized process parameters for rotational components

Process planning, as a critical stage integrating the design and manufacturing phase in a manufacturing environment, has been automated to meet the needs for higher productivity and lower production cost. Being an input to various systems such as scheduling and routing, process planning results are of great importance in the manufacturing stage. Though feature extraction and sequence optimization have been given much attention, the process parameters are rarely dealt with. This paper focuses on the development of a new generative computer aided process planning (CAPP) framework for rotational components. The developed framework includes modules for feature extraction based on CAD application programming interfaces, determination of the optimum sequence and generation of optimum process parameters. The optimization of the machining operations is achieved using the evolutionary technique. The approach resulted in the reduction and prediction of machining time and cost. The framework is demonstrated with a case study.     

A generative process planning system for parts produced by rapid prototyping

This paper presents a generative process planning system for parts produced by the rapid prototyping process (i.e. fused deposition modelling–FDM). The proposed process planning involves optimal selection of orientating the model with a proper support structure and then provides an intelligent slicing methodology, such as direct or adaptive, to minimise the built up time, keeping the geometry and cusp height errors in control. Pre- and post-slicing processes have been used to minimise the sliced data error. The Computer Aided Process Planning (CAPP) model has been arranged into five modules: orientation, support structure generation, slicing, path planning and Numerical Control (NC) program generation, and model build up. The CAPP model has been implemented in C language having a unique methodology consisting of 42 simplified steps. The CAPP model has been tested for several examples and shows satisfactory results.     

销钉类零件的机加工工艺规程的自动生成研究

本文介绍一个面向销钉类零件的基于特征的参数化CAPP系统．利用成组技术将销钉分类编码,设计主样件的工艺规程模板．根据零件编码选择工件类别,输入零件的设计尺寸和公差,设定每种加工方法的加工余量,就可以计算出各道工序的尺寸,自动生成工序图．根据企业标准,各工序尺寸的公差实现自动分配,并由系统校验余量公差,最终生成完整的机械加工工艺规程．     

基于用户的CAPP零件编码系统的研究

介绍了一个基于用户的面向多品种零件机械加工的ＣＡＰＰ系统,主要介绍了其中零件信息处理方法,并讨论了适于多种零件的信息编码系统和工艺设计系统的信息集成问题。     

DESIGN, DEVELOPMENT AND IMPLEMENTATION OF AN INTEGRATED GROUP TECHNOLOGY AND COMPUTER AIDED PROCESS PLANNING SYSTEM

This paper discusses a Group Technology (GT) and Computer Aided Process Planning (CAPP) installation at JLG Industries, Inc., an international manufacturer and marketer of specialized hydraulic machinery. An efficient architecture for the design, development and implementation of the system is presented along with system design requirements and characteristics. A GT software shell is described, and for the architecture that is defined, a formal model of the process planning system is developed. The model is used as the basis for the creation of a generic semi-generative CAPP system. Implementation of the model along with experience with the system is included. Run time examples of the system are provided to illustrate the features of the system.     

GT—CAPP与FMS仿真器集成系统

为了适应ＦＭＳ的柔要求，ＣＡＰＰ系统需要产生多个工艺方案，为此本文开发了ＧＴＣＡＰＰ与ＦＭＳ仿真器相结合的集成式原型系统。     

基于PDM的交互式多用途CAPP系统设计

本文介绍了一种基于ＰＤＭ的计算机辅助工艺设计,该系统是根据零件图或装配图的标题栏的信息,建立零件的产品目录树。     

FMS中CAPP与CAM集成技术的研究

介绍了一个适用于FMS的CAPP／CAM集成系统。它由创成法CAPP系统，NC自动编程系统和它们之间的接口等主要部分组成。系统采用基于特征的零件描述方法作为集成环境下统一的零件信息模型。由CAPP系统生成的工艺规程，通过接口文件自动传输给NC编程系统，经过特征识别后，从特征NC程序库中调用相应的特征数控程序，实现NC自动编程，为检验NC程序的错误，系统还具有刀具轨迹仿真功能，系统用户界面友好，经加工验证，可用于生产。     

General information model for representing machining features in CAPP systems

Today, the generality of computer-aided process planning (CAPP) systems and their standardization do not achieve satisfactory standards levels for industry. One of the major causes here is the difficulty of integration with computer-aided design applications, due mainly to the product model used. It is therefore necessary to identify models that are general with regard to the products, but at the same time suitable for CAPP. A product model suitable for CAPP must represent the product conceptually, enabling the development of process planning functions that operate with manufacturing concepts. It is therefore necessary to develop product information models using this philosophy. The present paper focuses on this problem and proposes an information system for representing the product for internal CAPP use. It is geared towards representing all of the part information (necessary for manufacturing) integrally with the machining features and under the same concept as these features. To this end, one of the main characteristics of the model is the absence of conventional geometric entities. The application domain of the model proposed is the assignment of processes and machines in machined parts. The GF-CAPP system has revealed that the advantages of using this type of product model in CAPP are its generality with regard to the product and the ease of developing functional procedures that are general, simple and independent.     

基于特征的喷射式真空泵零件建模技术

将基于特征的参数化设计方法应用于喷射式真空泵零件的CAD／CAPP/CAM集成系统，提出了一种真空泵零件的建模技术。     

A modular architecture for rapid development of CAPP systems for agile manufacturing

Current manufacturing planning software systems, such as computer aided process planning (CAPP) systems, are general and in a closed form. It is very difficult to modify these systems to respond to a user's dynamically changing needs. These systems are no longer suitable for agile manufacturing. This paper presents research aimed at developing a novel architecture for the rapid development of CAPP systems. The architecture supports the construction of CAPP systems from prepackaged, plug-compatible software components. Specifications of the architecture and its building blocks are defined. Several important issues in architecture implementation are discussed, and an experimental system is illustrated. Finally, an Internet-based distributed CAPP system architecture is presented as a preview of next generation CAPP system development.     

箱体零件CAD／CAPP／CAM集成系统的研究与实践

在ＣＩＭＳ环境下，针对箱体零件ＣＡＤ、ＣＡＰＰ、ＣＡＭ信息集成的功能需求，在基于特征的箱体零件信息模型、工艺计划模型与服务于工艺设计的制造环境模型的支持下，开发出了特征造型，工艺设计及加工过程仿真与ＮＣ编程等子系统，从而完成了一个集成化的箱体零件ＣＡＤ／ＣＡＰＰ／ＣＡＭ系统。     

基于AutoCAD平台下装配图明细表生成系统的开发

提出了在AutoCAD平台下装配图的明细表系统的算法及开发过程,从而实现了装配图明细表管理过程的自动化和智能化,提高了设计效率,保证了图纸信息与明细表的汇总信息高度一致,因而更有利于实现计算机辅助工艺设计(CAPP).     

面向产品的集成化CAPP系统研究

本文通过对传统的ＣＡＰＰ系统存在问题的分析,提出了建立集成环境下面向产品的ＣＡＰＰ系统的观点,并依据这种观点对集成环境下面向产品的ＣＡＰＰ系统的设计思想、体系结构、集成模式和关键技术进行了探讨。     

基于B—rep模型的特征CAD系统

提出了一种特征分离表达模式，将几何信息与特征参数信息分别表达在Ｂ－ｒｅｐ模型和参数化数据模型中，但又互相关联，可较为完备地表达零件各层次信息。讨论了特征关系的表达策略，提出了特征设计中有效性检验的必要性和算法。     

A simulated annealing-based optimization algorithm for process planning

Computer-aided process planning (CAPP) in the past typically employed knowledge-based approaches, which are only capable of generating a feasible plan for a given part based on invariable machining resources. In the field of concurrent engineering, there is a great need for process planning optimization. This paper describes an approach that models the constraints of process planning problems in a concurrent manner. It is able to generate the entire solution space by considering multiple planning tasks, i.e. operations (machine, tool and tool approach direction), selection and operations sequencing simultaneously. Precedence relationships among all the operations required for a given part are used as the constraints for the solution space. The relationship between an actual sequence and the feasibility of applying an operation is also considered. An algorithm based on simulated annealing (SA) has been developed to search for the optimal solution. Several cost factors including machine cost, tool cost, machine change cost, tool change cost and set-up change cost can be used flexibly as the objective function. The case study shows that the algorithm can generate highly satisfying results.     

Methodology for set-up planning automation of turned parts

This paper presents an automatic set-up planning module integrated in a CAPP system for rotational parts to be machined on a lathe. The developed system determines the possible set-up combinations that are necessary for a complete machining of the part as well as the order of each set-up and the surfaces to be used for clamping the part. The applied methodology takes into consideration constraints such as the geometry of both the stock and the final part, the geometry and the capacity of the chuck, and the part tolerances. In general, these constraints allow the system to obtain several valid solutions for clamping the part. Some criteria based on the clamping force and the value of tolerances have been considered in order to establish a preference order among these solutions. Finally, the analysis of linked tolerances and the tool approach direction to each surface determine the sets of surfaces to be machined within each set-up. An example part is used in the course of the paper to illustrate conveniently the methodology, and two additional case studies prove that this methodology is adequate for the solution of real cases.     

计算机辅助工艺规程设计系统的体系结构研究

在现代机械制造业中,计算机辅助工艺规程设计(computer aided process planning,简称CAPP)具有重要的理论意义和实际需求。本文旨在建立一个适合企业实际需要的、完善的CAPP系统体系结构,重点在CAPP体系结构理论方面的研究,并在此基础上提出适应应用环境变化的工艺规划方法和能够被企业接受的CAPP系统开发的模式。