中点误差控制宽行加工算法  

A Middle-point-error-control Method in Strip-width Maximization-machining

作　　者：陈志同[1,2] 乐毅 徐汝锋[1,2] 

机构地区：[1]北京航空航天大学机械工程及自动化学院,北京100191 [2]国防科技工业高效数控加工技术研究应用中心,北京100191 [3]北京卫星制造厂,北京100190

出　　处：《机械工程学报》2011年第1期117-123,共7页Journal of Mechanical Engineering

基　　金：国家自然科学基金(50875012);国家高技术研究发展计划(863计划;2008AA04Z124);科技重大专项课题(2009ZX04001-141);北京市教育委员会共建专项资助项目

摘　　要：现有的几种利用圆环形切削刃刀具实现五轴宽行加工刀轨生成算法在计算曲率突变曲面时存在刀心波动问题,不利于提高加工效率和保证加工质量。通过分析现有宽行加工算法刀位调整过程,认为产生刀心波动的两个理论因素:行宽致波动量和刀轴致波动量,其中行宽致波动量是由于相邻两刀位行宽大小不一致导致的刀心波动量,刀轴致波动量是由于曲面曲率变化导致刀具的旋转自由度变动产生的刀心波动量。虽然存在两者异号相抵的情况,但也存在同号时增大刀心波动的情况。鉴于问题复杂性,从理论上消除行宽致波动量产生的刀心波动出发,提出中点误差控制刀位优化算法,该算法中的刀心波动仅由刀轴致波动量产生。算法以有效特征线段中点定位刀具,以最大加工行宽为目标,对刀具姿态进行优化。编制了计算程序并对某种螺旋桨试件进行试切试验。通过与Sturz算法和多点法(Multi-point method,MPM)结果比较,验证该算法在减小刀心波动、改善刀轨光顺性和提高加工效率方面的有效性。The tool center fluctuation problem commonly exists in the current machining strip-width maximization methods for 5-axis finish machining of complex surfaces with abrupt curvature change by using a torus cutter.This has negative impact on machining efficiency and quality improvement.After analyzing the tool position adjusting process of those strip-width maximization machining methods,the reasons for fluctuation caused by cutting strip-width（FCCS） and fluctuation caused by tool axis（FCTA） are decomposed.FCCS is the tool center fluctuation caused by the different machining strip-widths between two adjacent tool positions,and FCTA is the tool center fluctuation caused by tool freedom resulted from surface curvature variation.Although the influences by FCCS and FCTA may counteract with each other,the tool center fluctuation may be aggravated when they are both positive and both negative.A mid-point-error-control method（MPEC） for tool position optimization which can eliminate FCCS is proposed.Thus,FCTA is the only causation of the tool center fluctuation in this method.The torus cutter is firstly positioned by the mid-point on the effective-character-curve-segment（ECCS）,and the other 2 degrees of freedom（DOF） are adjusted to obtain the maximum strip-width.The corresponding program of this method for an airscrew part is developed and the cutting experiment is conducted.Through comparison among the proposed method,the Sturz algorithm and the multi-point method,the effectiveness of MPEC in tool path smoothing and machining efficiency improvement for complex surface machining is validated.

关 键 词：刀心波动 中点误差控制 宽行加工 复杂曲面 

分 类 号：TP391[自动化与计算机技术—计算机应用技术]