创成式 CAPP 中的工步排序与工艺决策

在若干特征构成的零件工艺过程设计中,工步顺序不能有效地确定。本文通过对工艺设计过程的分析,结合杭州叉车总厂创成式ＣＡＰＰ系统（ＨＣ－ＣＡＰＰ）的开发,提出特征排序、工步排序与工艺决策等优化、决策方法确定符合车间作业资源能力的零件工艺加工路线。     

基于三维零件模型的工艺路线设计方法研究

针对基于三维CAD的计算机辅助工艺设计(Computer Aided Process Planning,CAPP)的发展需求,提出了一种基于三维零件模型的工艺路线设计方法。从零件三维模型中提取加工特征,建立以加工特征为核心的工艺信息模型,有利于与上游CAD以及下游CAM的集成和信息共享。在工艺信息模型基础上建立以加工元为基元的工艺决策模型,通过聚类和排序约束实现工序/工步的确定和排序,实现工艺决策过程的算法化。通过飞机双面大框零件实例说明了该方法是简单有效的。     

箱体零件工艺路线分层决策方法

箱体零件特征面多，加工方法多，工艺路线决策的规模大，决策算法复杂。文章将工艺路线决策过程分解成特征工艺决策、加工路线排序、工序决策、工步决策四个层次。决策过程中，将决策算法与零件的具体形状特征、加工方法相分离，简化了算法，提高了决策算法的实用性和灵活性。     

航空发动机整体机匣铣-车复合加工工艺优化

针对加工过程中的多次工件转位和刀具更换对加工质量和生产效率的重要影响,在分析工步排序和合理确定辅助时间的基础上,建立了以最短辅助时间为目标函数的工步排序优化模型,利用自适应遗传算法完成工艺规划的全局优化决策,获得了最佳工步排序和最短辅助时间.优化过程中,为了使工步序列满足工艺约束规则,首先根据工艺约束规则确定工步优先关系矩阵,然后利用优先关系矩阵对工步序列进行校验和调整.通过工步优化,有效地降低了发动机机匣铣-车复合加工过程中的辅助时间,达到了提高生产效率和加工质量的目的.     

箱体零件数控加工路线研究

针对箱体类零件的特点,探讨了箱体零件加工工艺路线的确定原则和程序;阐述了箱体类零件的特征型面描述方法;建立了不同特征的加工方法匹配规则库,实现了零件特征要素加工方法的决策;同时研究了零件一次装夹的优化问题,建立了数学模型.实现箱体零件特征要素加工方法的决策和工步排序,最终得到了箱体零件在加工中心上的最优工艺路线.对传统工艺过程进行优化具有非常重要的工程实用价值.     

CAPP系统工艺决策过程的AOV—网表示法及拓扑排序分析

提出了修正ＡＯＶ－网和修正拓扑排序的概念，分析了用修正ＡＯＶ－网表示工艺决策过程内部各部分之间的相互关系和用修正拓扑排序确定工艺决策过程步骤的方法。指邮了用该方法分析工艺决策的关键技术。     

工艺方案评价的不确定语言多属性决策研究

为达到工艺资源重用和智能辅助工艺决策的目的,提出了一种不确定语言评价与多属性决策方法相结合的多工艺方案评价与决策模型。在该模型中,通过工艺聚类和关联,从企业工艺数据仓库中进行多工艺方案提取,在此基础上形成多工艺评价方案集。选择已建立的评价目标属性集作为评价依据,并结合企业生产的内外部条件,列出各属性的不确定语言型评价。在此基础上运用不确定拓展有序加权平均算子,对各工艺方案进行评估并排序,进而得到相对较优工艺方案。不确定拓展有序加权平均算子中所使用的加权向量需要按照加工任务的具体要求确定,从而提高了算法的灵活性。     

基于约束矩阵与遗传算法的工艺加工顺序决策研究

随着现代制造技术的快速发展,CAPP越来越多的受到企业的广泛关注,工艺加工顺序决策是CAPP系统中最重要的工艺决策技术之一。针对CAPP技术中工艺加工顺序决策难题,提出了基于约束矩阵和遗传算法的智能化工艺决策方法,建立了基于遗传算法的工艺加工排序问题的数学模型,利用约束矩阵来描述工艺加工元间的优先关系,研究了基于遗传算法的工艺加工顺序决策过程,包括基因编码、适应度函数的设计、选种、基因重组和变异等。最后,以C#为开发语言,以Visual Studio2008为开发平台,开发成功了工艺决策系统模块并用实例验证了该方法的可行性。     

遗传算法在机械零件加工工艺决策中的应用和实现

通过对箱体类零件典型加工路线的分析，结合遗传算法的特点，建立了机械零件加工工艺决策的数学模型，提出了基于遗传算法的工步排序优化方法。并以箱体类零件为例，阐述遗传算法在零件加工工艺决策过程中的应用和实现。     

基于典型工序MBD模型的工艺路线决策研究

为了提高三维数字化制造工艺设计智能化水平,简化工艺路线决策过程,提出一种基于典型工序MBD模型的工艺路线决策方法.在制造特征分类的基础上构建了典型工序MBD模型,该模型融合了工艺决策规则、加工方法、机床和工装等工艺信息.通过加工特征与典型工序MBD模型匹配,减少了工艺决策步骤.为保证工序安排的合理性,定义加工元为最小信息实体,通过加工元的合并、排序,得到最优工艺路线.以飞机双面大框结构件的三维数字化工艺设计实例验证了所提方法的有效性.     

Workpiece modelling for computer-aided process planning

Different concepts can be applied for representation of workpiece data for CAPP. Instead of waiting for future standards, a practical method is required, which can be used for actual workpieces or those that have been designed in the past by using already existing CAD systems. Therefore, for developing the CAPP system an approach has been chosen which consists of (1) a structure and geometry recognition of the workpiece and (2) an editor for technological data.This paper shows the main characteristics of a workpiece model which can be used for process planning. The results of an analysis of workpieces in industry give an overview of the topological relationships between geometrical elements which is an essential part of workpiece modelling for future design and planning systems. Also, a link between the workpiece model and the CAPP system is presented and briefly discussed.     

Analytic Hierarchy Process Based Decision Modelling in CAPP Development Tools

Process planning decision modelling is a main barrier in the research on CAPP development tools, and also a bottleneck hampering the process of pragmatisation and commercialis-ation of CAPP. Analytic hierarchy process (AHP), is a mathematical decision modelling tool for solving complicated process planning decision problems by decomposition, determination and synthesis. AHP can deal with universal modelling of process planning decision-making, which is difficult to describe quantitatively, by integrating quantitative analysis with qualitat-ive analysis.     

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.     

Computer-aided process planning: A state of art

During the last decade, computer-aided process planning (CAPP) has received much attention both from researchers and practitioners. One of the reasons for this is the role of CAPP in reducing throughput time and improving quality. An attempt has been made in this paper to review the existing literature with the objective of gaining insights into the design and implementation of CAPP systems. The literature available (1989–1996) on CAPP has been reviewed based on the types of systems. The advantages and disadvantages of such systems are presented. Finally, future research directions are indicated.     

Computer-aided process planning for NC tool path generation of complex shoe molds

This paper presents a computer aided process planning (CAPP) system for numerical control tool path generation of complex shoe molds. This CAPP system includes both the automation of auxiliary boundary curve generation and machining strategies. The automation of auxiliary boundary curve generation and machining strategies make tool path generation more accurately and efficiently. Traditional shoe mold making is a very tedious process. Even with the utilization of computer-aided design and computer-aided manufacturing (CAD/CAM), the CAM process requires long hours of tool path programming and debugging. It would also take a long time to calculate (sometimes several hours) the tool path for complex athletic footwear. In order to reduce the tool path editing and programming time, this paper proposes the use of CAPP to reduce processing time and increase efficiency. It is difficult, if not impossible, to develop a generic CAPP system that can generate a process plan to solve general production problems. However, it is quite possible to capture the domain knowledge of a certain production process and embed that knowledge into a CAPP system. We prove, by using such a system, that a very complicated process planning problem can be overcome by a knowledge-based CAPP approach. With such an approach, the traditional manufacturing process of shoe molds can be converted to an automatic manufacturing process with the CAPP system. In fact, shoe molds for real production have been created using the developed CAPP system, demonstrating the effectiveness of this approach. In this paper, we show that several complex and different shoe molds and their machining strategies were automatically planned by the proposed CAPP system. The result of a comparison between the CAPP system with the traditional approach is presented and discussed.     

SMT-TAB: A process planning system for PCB assembly using TAB and SMT

Process planning is a critical function in any manufacturing domain. This is especially true in the electronics manufacturing area where substantial heuristic and experiential knowledge is commonly used during process plan development. While research in computer-aided process planning (CAPP) has tended to concentrate in the machining realm, few CAPP systems have been developed for electronics manufacturing applications and more specifically for the printed circuit board (PCB) assembly domain. Besides, the CAPP systems that have been developed for this area have dealt with either insertion mount or surface mount PCB assembly processes only.Tape automated bonding (TAB), though a relatively new technology, is gaining importance in electronics assembly owing to its inherent advantages. The advent of fine pitch technology together with the ever increasing need for more inputs/outputs and greater pin counts in integrated circuit applications has enhanced the use of TAB technology in electronics manufacturing. This trend has been further augmented by the increasing need for compactness in consumer electronics.This research designed and developed a prototype CAPP system for the PCB assembly domain. The system developed generates a process plan for PCBs populated with surface mount and/or TAB components. An artificial-intelligence based expert system approach has been used in the design and development of the CAPP system. Outputs generated by the system are presented along with ideas for future research.     

Annotated bibliography on computer-aided process planning

Computer-aided process planning (CAPP) has attracted great research interest for the last two decades and a large volume of material has been published on the subject. With the introduction of contemporary manufacturing philosophies such as concurrent engineering, agile manufacturing and the like, the research in process planning has been gradually transformed into an inter-disciplinary and multi-faceted problem domain. By compiling, classifying and annotating a sample of articles published in the last few years, the paper provides a logical organisation of the literature on process planning. Some rudimentary analysis is included based on observations made during the compilation process.     

A multi-objective decision-making process of supplier selection and order allocation for multi-period scheduling in an electronic market

Supplier selection is a multi-criteria problem which includes both tangible and intangible factors. In these problems when suppliers have capacity or other different constraints, two questions persist: which suppliers are the best and how much should be purchased from a selected supplier? Here, we propose an integrated approach of analytic hierarchy process (AHP), Technique for Order Preference by Similarity to an Ideal Solution (TOPSIS), and multi-objective nonlinear programming to consider both tangible and intangible factors in choosing the best suppliers and define the optimum quantities among selected suppliers to maximize the total value of purchasing and minimize the budget, total penalized earliness and tardiness, and defect rate. The priorities are calculated for each supplier by use of AHP. TOPSIS is applied to rank the suppliers. Finally, using the obtained weights, the optimal quantities of order to the suppliers are clarified in multi-period horizon. An application study presents the validity and efficiency of the proposed model. Moreover, a performance analysis has been worked out on the numerical example to investigate the capability and effectiveness of the results.     

Algorithms for computer-aided generative process planning

Process planning is the function within a manufacturing facility that establishes the machining processes and parameters to be used so as to convert a piece-part from its initial form to the final form predetermined on an engineering drawing. Computer-aided process planning (CAPP) has become a major focus of manufacturing automation as it forms the interface between computer-aided design (CAD) and computer-aided manufacturing (CAM). Issues in CAPP include part representation, process selection, alternative process-plan generation, intermediate surface and tolerance determination, and operation sequencing. This paper focuses on quantitative models for determining cutting dimensions and tolerances for intermediate surfaces, and on a heuristic for sequencing cutting operations.     

A blackboard-based process planning system for the surface mount manufacture of PCBs

This paper describes a real-time computer-aided process planning (CAPP) system for printed circuit board (PCB) assembly using surface mount technology. The prototype, dynamic, realtime CAPP system described uses a blackboard to integrate multiple knowledge sources (knowledge bases) in implementing the process planning procedure. The CAPP system is implemented using the expert system environment (ESE) and structured query language (SQL). The system uses two subsystems (knowledge bases). They are a planning subsystem which performs the static process planning task and a dynamic information processing subsystem which considers the real-time changes on the shop floor and routes the PCB assembly flow. The integrated system developed generates process plans that can be implemented in real time. The use of the blackboard concept for CAPP architecture is unique and well suited for this task.