基于制造资源约束的CAPP研究与开发

发布时间：2018-12-13 03:30

【摘要】：随着CAD技术的广泛应用和数控加工技术的不断进步,建立先进的集成制造系统已成为机械制造企业进行产业结构升级,谋求长远发展的重要举措。CAPP作为CAD /CAM集成系统的重要模块,是各模块信息交汇的中心,也是集成系统与企业环境相契合的纽带,其信息处理能力很大程度上决定着整个系统的性能,因而对CAPP的研究特别是在CAD/CAM集成环境下的CAPP研究具有重要而迫切的实际意义。在此背景下本文根据某齿轮箱制造企业的实际需要,开展了面向CAD/CAPP集成的,基于制造资源约束的箱体类零件的计算机辅助工艺设计的开发与研究。通过研究制造过程与工艺决策流程对制造资源的需求,在对制造资源进行分类的基础上,对各类资源的属性进行分析与归纳,从而建立相应的资源模型,进而完成制造资源库的建立和制造资源管理模块的开发。通过对制造资源的管理,一方面可以实时获取企业现有资源的变化情况以及由此引发的加工能力的变化情况,并以特征文件的形式提供给CAD模块,以辅助产品设计人员进行合理设计,及时发现设计与企业加工能力之间的矛盾,有利于保证设计的可制造性；另一方面也为后续的工艺决策提供了制造资源约束,使得工艺排序、刀具选择等工作只能在可行域中进行,从而保证了最终生成的加工工艺的可行性。以特征文件作为CAD/CAPP的信息交换接口,CAPP从特征文件中获取零件加工特征信息进行工艺决策。在工艺决策过程中,考虑了铸造工艺对毛坯的影响,通过引入铸造工艺知识对零件毛坯进行合理化修改与尺寸合理化计算,得到各加工特征合理的铸造毛坯尺寸,并依据零件的特征文件进一步生成毛坯特征文件,供CAD读取、显示和修改,从而使以往的CAD/CAPP集成系统得以进一步延伸到毛坯铸造工艺领域。采用改进的遗传算法,以成本最低,效率最高为目标进行多目标的工艺优化排序和机床优化选择。通过将两种变异方式相结合,有效地降低了算法的迭代运算量,提高了优化效率。在完成工艺排序、机床与刀具选择、切削用量确定的基础上,针对数控加工情况,进一步生成了数控加工工序的刀轨,并对同一装夹下同一刀具的刀轨进行了连接,从而为后续CAM模块的NC代码生成准备了必要的基础。
[Abstract]:With the wide application of CAD technology and the continuous progress of NC machining technology, the establishment of advanced integrated manufacturing system has become a mechanical manufacturing enterprise to upgrade the industrial structure. As an important module of CAD / CAM integration system, CAPP is the center of information intersection of each module, and also the link of integration system and enterprise environment. Its information processing ability determines the performance of the whole system to a great extent, so the study of CAPP, especially the CAPP research in the CAD/CAM integrated environment, is of great and urgent practical significance. In this context, according to the actual needs of a gearbox manufacturing enterprise, the development and research of computer aided process planning for CAD/CAPP integrated box parts based on manufacturing resource constraints are carried out. By studying the requirement of manufacturing resources in manufacturing process and process decision process, on the basis of classifying manufacturing resources, the attributes of all kinds of resources are analyzed and summarized, and the corresponding resource model is established. Then the establishment of manufacturing resource database and the development of manufacturing resource management module are completed. Through the management of manufacturing resources, on the one hand, we can obtain the changes of the existing resources of the enterprise and the change of the processing ability caused by them in real time, and provide the CAD module in the form of feature files. The reasonable design by the assistant product designer can find the contradiction between the design and the processing ability of the enterprise in time, which is helpful to ensure the manufacturability of the design. On the other hand, it also provides the manufacturing resource constraints for the subsequent process decision, so that the process ranking and tool selection can only be carried out in the feasible domain, thus ensuring the feasibility of the final production process. The feature file is used as the information exchange interface of CAD/CAPP, and CAPP acquires the machining feature information from the feature file for process decision. In the process of process decision, the influence of casting technology on the blank is considered. By introducing the foundry technology knowledge, the reasonable size of casting blank is obtained by introducing the knowledge of casting technology into the rational modification and calculation of the blank size, and the reasonable size of the casting blank with reasonable processing characteristics is obtained. According to the feature file of parts, the blank feature file is further generated for CAD to read, display and modify, so that the former CAD/CAPP integrated system can be further extended to the field of blank casting technology. An improved genetic algorithm is used to optimize process sequencing and machine tool selection with the aim of lowest cost and highest efficiency. By combining the two mutation methods, the iterative operation of the algorithm is effectively reduced and the optimization efficiency is improved. On the basis of finishing the process ranking, selecting the machine tool and cutting tool, and determining the cutting parameters, the tool track of the NC machining procedure is further generated according to the NC machining condition, and the cutter track of the same tool is connected under the same mounting. Thus for the subsequent CAM module NC code generation to prepare the necessary foundation.
【学位授予单位】：哈尔滨工程大学
【学位级别】：硕士
【学位授予年份】：2011
【分类号】：TH166

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