Abstract: To adapt to the development trend of special-shaped screw's integrated manufacturing technology,a Numerical Control (NC) machining method based on STandard for the Exchange of Product model data (STEP) was proposed.The STEP data model of helical surfaces was identified and the extraction method of the geometric information was researched.An approach to obtain the helical surfaces'parameters was presented by using NURBS' model.The whirling process of helical surfaces and its tool path calculation were investigated.A Computer Aided Manufacturing (CAM) system aiming at special-shaped screws was proposed.The system consisted of information extraction and analysis,feature recognition,tool path calculation,tool path validation and post-processing modules,which realized the integration between design system of special-shaped screws and NC machining system.The main function of the system had been implemented and verified in the machining test.

Key words: standard for exchange of product model data, AP203 procotol, screw;numerical control machining, computer aided manufacturing

摘要： 为了适应异型螺杆集成制造技术的发展趋势,研究了螺旋面的STEP数据模型和内旋风铣削技术,提出一种基于STEP的异型螺杆数控加工方法。研究了螺旋面的STEP数据模型和几何信息的提取方法;给出了利用非均匀有理B样条模型获取螺旋面参数的方法;研究了螺旋面的内旋风包络铣削加工工艺及其刀轨计算方法;针对异型螺杆设计了一种计算机辅助制造系统,该系统包括STEP文件读取分析、特征识别、刀轨计算、刀轨验证、后处理等模块,实现了异型螺杆的设计系统与数控加工系统之间的有效集成。该系统的主要功能已实现并在实际加工中获得了验证。

关键词: 产品模型数据交换标准, AP203协议, 螺杆, 数控加工, 计算机辅助制造