轴类零件工序图自动绘制的方法和系统研究

发布时间：2019-01-12 19:54

【摘要】：计算机辅助工艺设计(Computer Aided Process Planning)是连接CAD/CAM的桥梁,是实现CIMS的关键环节,鉴于CAPP在制造业中的重要地位,一直成为国内外学者关注的焦点。工序图生成系统是CAPP系统的一个重要组成部分,它对于提高工艺设计的效率和质量实现工艺设计的标准化和提高CAPP系统的实用性具有重要意义,但是工序图绘制的自动化程度低是CAPP技术进步的主要瓶颈之一。目前,工序图自动生成方法多采用逆序方式,这不仅可以充分利用零件图信息,相对正序生成方式也更简单,易于实现,但是工序图生成的自动化程度却急需提高。轴类零件是较简单的回转体零件,本课题将以轴类零件为研究对象,综合运用AutoCAD提供的AutoLISP二次开发工具,Microsoft Visual Basic可视化编程开发软件,数据库技术,计算机辅助工艺尺寸链求解技术等,深入研究CAPP系统中工序图形化的理论与开发技术,提出了一种轴类零件的工序图绘制自动化程度较高的新方法。本课题的研究重点与工作成果如下： (1)零件信息的编码存储。首先根据轴类零件结构的特点,以零件分类编码的方法为基础,开发出一种适合本系统的二维零件图图元的命名编码规则。然后以人机交互的方式获得特征参数,在绘制参数化特征的同时,将图元句柄定义成规则化的名称,并将其存储在AutoLISP语言擅长处理的表结构中,实现了轴类零件的信息存储,为工序图绘制模块提供基础。 (2)工序图的自动生成。工序图的绘制采用基于特征的图形元素修改方法,根据在工序图生成过程中,特征修改遵循的不同原则,把传统机械加工工艺文件中的工序类型重新分类组合,提出了一种加工工艺信息新的分类方法。按照本文提出的方法将机械加工工艺信息代码化,生成AutoLISP程序专用的外部数据文件。然后读入数据文件中的工序代码,由计算机独立生成工序简图,并保存输出。最后在系统提供的可视化界面下,从块库中选择标注符号,实现定位、夹紧、粗糙度等特殊符号的快速标注。 (3)直线工艺尺寸链的计算机辅助求解。首先借助工艺尺寸链跟踪图的表述方法,将工艺尺寸信息转化为多个矩阵数据；然后将这些尺寸信息矩阵输入计算机,由计算机完成结果尺寸链的跟踪寻找,建立尺寸链矩阵；再由计算机进行图样公差和工序余量的校核；最后完成各工序尺寸的计算和输出。
[Abstract]:Computer-aided process planning (Computer Aided Process Planning) is a bridge connecting CAD/CAM and a key link to realize CIMS. In view of the important position of CAPP in manufacturing industry, CAPP has always been the focus of attention of domestic and foreign scholars. Process diagram generation system is an important part of CAPP system. It is of great significance to improve the efficiency and quality of process planning to realize the standardization of process planning and to improve the practicability of CAPP system. However, the low degree of automation in drawing process diagrams is one of the main bottlenecks in the progress of CAPP technology. At present, most of the automatic generation methods of process drawing adopt reverse sequence method, which can not only make full use of part drawing information, but also be simpler and easier to realize than the positive sequence generation method, but the automation degree of process drawing generation needs to be improved urgently. Shaft parts are relatively simple parts of rotary parts. This subject will take shaft parts as research object, and make comprehensive use of AutoLISP secondary development tool, Microsoft Visual Basic provided by AutoCAD to develop software and database technology. In this paper, the theory and development technology of process graphics in CAPP system are deeply studied, and a new method of automatic drawing of shaft parts is proposed. The research focus and work results are as follows: (1) coding and storage of part information. Firstly, according to the characteristics of shaft parts' structure and the method of part classification and coding, a naming coding rule of 2D part drawing elements suitable for this system is developed. Then, the feature parameters are obtained by human-computer interaction. When drawing parameterized features, the reference handle is defined as a regular name, and stored in the table structure which is good at processing in AutoLISP language, and the information storage of shaft parts is realized. Provides the foundation for the process drawing module. (2) automatic generation of process diagram. The drawing of process map is based on feature based graphic element modification method. According to the different principles of feature modification in the process of process diagram generation, the process types in the traditional machining process file are reclassified and combined. A new classification method for processing process information is presented. According to the method proposed in this paper, the machining process information is coded to generate the external data file for AutoLISP program. Then read into the data file process code, computer independent production process diagram, and save the output. Finally, in the visual interface provided by the system, the marking symbols are selected from the block library to realize the fast marking of special symbols such as location, clamping, roughness and so on. (3) Computer-aided solution of linear process dimension chain. Firstly, the process dimension information is transformed into a plurality of matrix data by using the description method of the process dimension chain tracking diagram, and then these dimension information matrices are input into the computer, and the size chain matrix is established by the computer to complete the tracing and searching of the result dimension chain. The design tolerance and process allowance are checked by computer, and the calculation and output of each process size are finished.
【学位授予单位】：华东理工大学
【学位级别】：硕士
【学位授予年份】：2012
【分类号】：TH133.2;TH162;TP391.72

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