基于STEP-NC的工艺过程设计与优化技术研究  

Exploring Process Planning and Optimizing in STEP-NC-Based CAPP

作　　者：田锡天[1] 仝春民[2] 张振明[1] 贾晓亮[1] 

机构地区：[1]西北工业大学机电学院,陕西西安710072 [2]西安科技大学机械工程学院,陕西西安710054

出　　处：《西北工业大学学报》2007年第2期261-265,共5页Journal of Northwestern Polytechnical University

基　　金：航空科学基金(02H53056)资助

摘　　要：为了简化工艺决策过程的复杂性和实现工艺决策过程的模型化和算法化,在深入分析STEP-NC数据模型的基础上,针对数控工艺的特点,提出了元加工操作及制造特征加工链等概念,建立了支持非线性工艺设计的分步工艺决策过程;进而提出了基于排列和辅助时间的加工工步排序和优化的方法,实现了加工工步排序和优化过程的统一处理,使CAPP系统能够提供多个可选的工艺方案。通过一个基于STEP-NC的CAPP原型系统的实现及实例零件的工艺过程设计表明,所提出的工艺决策过程和优化方法是简单有效的。Aim. STEP-NC, formalized as ISO 14649, is a new interchangeable data interface between CAD/CAM system and CNC. As an important bridge between CAD and CAM, the CAPP based on STEP- NC is obviously different from the conventional CAPP in both its design principles and functions. So we now present our research results on exploring the process planning and optimizing in STEP-NC-based CAPP. Section 1 in the full paper introduces the STEP-NC data model given in ISO 14649. Section 2 explains a decision-making model established by us. Fig. 2 shows the entities and their relationships of process planning recommended by ISO 14649 except that we add two new entities called by us “ meta- machining operation” and “process chain of each manufacturing feature” respectively. Then, in Section 2, Fig. 3 shows the nine steps involved in process decision-making based on manufacturing features. With the help of Fig. 4, Section 3 explains a new method, based on permutation and total auxiliary time of all machining steps, for solving the problem of sequencing and optimizing of machining steps in a workplan. In particular, we derive eqs. （1）, （2） and （3） in the full paper for computing the auxiliary time of each machining step. We like to emphasize that our new method can simultaneously deal with both the sequencing and the optimizing. And the simplicity, feasibility and validity of our decision-making model and optimization method were tentatively confirmed by testing a prototype CAPP system.

关 键 词：STEP-NC 计算机辅助工艺过程设计 工艺过程优化 元加工操作 加工链 

分 类 号：TH164[机械工程—机械制造及自动化]