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三维工艺设计中的特征识别技术研究
Research on Feature Recognition Technology of 3D Process Planning
【作者】 董小忠;
【导师】 盛步云;
【作者基本信息】 武汉理工大学 , 机械制造及其自动化, 2011, 硕士
【摘要】 高效快捷的工艺设计方法是企业及时地把设计理念转化为真实产品的重要保证。工艺信息的获取是工艺设计的基础,其关键是如何从设计模型中直接获取工艺信息,特征识别作为工艺信息获取的重要方法一直是研究的热点。因此,本文针对三维工艺设计中的特征识别技术,采用切削体分解组合的方法进行研究,研究内容主要包括以下几个方面。结合工艺设计的实际情况,提出了切削体分解过程中的单元切削体、分割面、工序切削体等包含丰富工艺信息的概念。研究了单元切削体的建模方式,采用自定义扩展的属性邻接图描述本文所要构建的单元切削体,建立了车、铣等典型加工方法的单元切削体形式。针对不同设备的加工能力,研究了切削体分解成单元切削体的具体算法,阐述了分解流程及其中涉及到的凹边的判定依据,探讨了参与分解切削体的分割面的形成方法及其的分割准则。分析了工艺加工中基准先行、先面后孔、先粗后精等原则在分解算法中的表现方式。针对相同设备的加工能力范围,研究了相似单元切削体组合成工序切削体的方法及流程,分析了如何在组合过程中考虑工艺原则及空间几何约束等因素,并探讨了若干典型的工艺原则所对应的组合原则。探讨了非形状特征的识别方法,并结合切削体分解法对形状特征的识别阐述如何将识别的结果应用到工序切削体的工艺映射过程中。论文末尾给出了一个应用该算法识别某具体零件加工特征的实例,并在SolidWorks软件平台上实现了部分关键技术,从而验证了该方法在理论上的可行性。本文所研究的特征识别方法是在原有的切削体分解法基础上进行了扩展,创新之处表现在识别特征的过程中不仅考虑实体的几何拓扑信息,更融入了工艺原则的约束,与工艺设计的应用结合更为紧密。论文所研究的特征识别方法为提高工艺设计的自动化水平和智能化程度探索了一条新途径。
【Abstract】 The efficient and fast process planning method is important guarantee for enterprises to convert design concepts into real product quickly. The extraction of process information is basis of process planning, and the key point is how to extract process information from CAD models directly. As one of the most important method for extracting process information, feature recognition has been always became research hotspot. Therefore, feature recognition technology of 3D process planning has been researched in this thesis using delta volume decomposition and combination method. The main contents and works of this thesis are as follow.Combined with actual situation of process planning, the concepts of cell delta volume, partition surface, process delta volume in the decomposition process were put forward, and the concepts contain abundant process information. The modeling method of cell delta volume was researched. The cell delta volume models were builded by self-Defined Extended Attributed Adjacency Graph. The turning, milling and other typical cell delta volume were builded.According to different equipment processing capacity, the method of decomposing delta volume into cell delta volume was researched. The decomposition process and judgment rule of concave edge involved were expounded. The generating way and segmental rule of partition surface used to decompose delta volume were discussed. The reflect way in decomposition algorithm of principles in process planning about benchmark first, plane first, rough first. etc was analyzed.According to machining capabilities of the same equipment, the method and process of combining similar cell delta volume into process delta volume were researched. The factors of how to consider process principle and geometric constraint in the algorithm were analyzed. Some actual combination principles corresponding with some typical process principles were discussed.The recognition method of non form feature was discussed. Combined with form feature recognition using delta volume decomposition method, the method how to apply the result of recognition to process matching of process delta volume was expounded. In the end of the thesis, an example was given to explain how to recognize machining features of a actual part by the algorithm. Some key technology was realized in SolidWorks system. Therefore, the feasibility of the algorithm was proved in theory.The feature recognition method researched in this thesis is extension of exist volume decomposition. The innovation lies in the point that in the process of feature recognition, it considers not only geometric topology information, but also constraints of process rules. It combines with actual situation of process planning more closely. The feature recognition technology researched in this thesis explores a new way for enhancing automation level and deepening intelligence degree of process planning.
【Key words】 Feature Recognition; Process Planning; Delta Volume; Decomposition; Combination;