【作者】 谢波；

【导师】 黄正东；

【作者基本信息】 华中科技大学 ， 机械设计及理论， 2006， 硕士

【摘要】 随着市场竞争的加剧,为了缩短产品开发周期和降低制造成本,在产品的开发过程中,工业界普遍采用了新的设计理论和方法来缩短产品的设计开发周期。虽然现阶段工业界采取的新的设计方法和理论还存在着一些问题,但是也能够在很大程度上节省产品设计阶段的时间。而对于产品设计另一个阶段——工艺流程设计,目前的工艺设计工具都还不能很好的提高其效率,仍依靠工艺工程师的人工劳动来完成产品的工艺流程设计,这不仅浪费了人力、物力,更重要的是延长了产品推出市场的时间。针对这种情况,本文在研究和分析相关领域国内外现状的基础上,结合零件设计与工艺规划过程的特性以及它们之间的关系,提出了基于特征的零件重构技术和从设计特征到加工特征转换的工艺几何分析方法。首先,论文给出一种符合加工方式和方向要求的零件特征模型重构方法。该方法从零件三维几何模型出发,利用模型所隐含的信息,并根据零件特征加工方向和方式将零件重构。这些重构出来的模型是用串化的特征表示,用于后续的零件加工信息提取以及特征排序等步骤;所以,这里每种特征类型要能与零件某种加工方式相关联,以利于减少后续步骤的运算量,提高算法的效率。其次,论文提出一种从零件设计特征到加工特征的转换方法。零件特征模型重构方法所得到的结果作为特征转换方法的输入模型。在转换过程中将串化的零件特征模型不断与毛坯模型比较,得到其加工特征,然后再对加工特征集合进行去冗余并相互组合等处理,实现加工特征集合的优化。这些加工特征是无序的,为了支持工艺流程设计,还需要对这些特征进行排序处理。为此,论文还给出了特征顺序排列与优化方法。为验证本文所提出的理论和方法,采用Visual C++ 6.0编程语言,在UGII NX2/UG OPEN平台上开发了从设计特征到加工特征转换的原型系统,实现了零件三维几何模型的重构、转换、去冗余、组合和排序等系统功能,用实例验证了研究方法的正确性和有效性。最后总结了全文,并对开展进一步的研究工作进行了展望。更多还原

【Abstract】 Along with increasing of market competition, industries generally adopt the new theory and method to shorten the period of product design. Nowadays, there still exist some problems in the implementation of these theories and methods, but they can indeed save a lot of time during the design period. As another period of product design– period of process planning, there is no good tool which can be used to improve its efficiency, and, in general, process planning of product is completed almost manually by engineer. It not only consumes a lot of human and material resource, but also postpones the time for bringing the products to markets. To address this issue, after studying and analyzing the present status of part design and process planning both in China and abroad, an approach for converting design features in a part model into machining features is presented, which can be developed to a key technique for promoting the automation of process planning.The first work of this thesis is to present an approach for reconstructing part CAD models by selecting proper feature representations so that they are more consistent with machining processes. This method, with the 3D mathematical model of part as input, recognizes its connotative information, and then reconstructs the part model according to style and direction of process. The model reconstructed is expressed by a sequence of features, which are used in feature recognition, conversion and sorting in the next steps. Not only the features are associated with the style of part machining, but also the type of feature must be correspondent to one machining style. Thus, the efficiency of the following computation is improved.The second work of this thesis is to develop an approach for converting design features in a part model into machining features. The input data of the approach is the sequence of features constructed in the previous work. In the process of feature conversion, the sequence of part feature is compared with the blank model, and then machining features are constructed. But these features are out-of-order; there is no any relation with each other. So the machining features should be sorted so that they can be used in design process planning. In this sorting step, the process route would be created as many as possible, and then the best one would be chosen by process designer. As another option, it can be input to other software for the further process planning work.Based on the work mentioned above, a prototype system for part feature reconstruction, feature conversion, feature sorting on transformation of feature information has been developed to validate the ideas and methods proposed in this thesis. The software development platform is Visual C++ 6.0 and UG II NX2.0, and the prototype system mainly consists of four sub-modules; that is, feature reconstruction, conversion, merging and sorting. Some practical examples are used to validate the correctness and effectiveness of the research results. In the end of the thesis, some conclusions have been drawn and the future directions in the field are given.更多还原