叶片前后缘六轴电火花包络修整的误差敏度分析

Error Sensitivity Analysis of Six-axis EDM Envelope Dressing of Blade Leading and Trailing Edges Li ZhengCao LixinYu Zuyuan

为提高效率,解决手工研磨、电火花拷贝、电解加工等方法在航空发动机叶片前后缘加工过程中存在的种种问题,提出了一种六轴电火花包络加工方法对叶片前后缘进行修整。因电极制造、安装过程中会引入多项误差,为最大程度降低成本,制订合理化的公差约束,对UG进行二次开发,在不考虑放电间隙与电极损耗的情况下,按6级公差等级对已有的电极模型施加6个自由度方向的单项源误差和57种组合源误差。根据共轭曲面啮合理论,分析各源误差对最终包络加工误差的影响规律,得到此新工艺中需严格控制的误差敏感因素。结果表明:在其他条件相同时,单项源误差δ_(z)、δ_(C)的误差扩大倍数K分别为1.15和1.61,对包络加工误差影响较小;组合源误差δ_(xB)、δ_(yA)的误差扩大倍数为10.46和8.53,对包络加工误差影响较大,应严格控制。

In order to improve efficiency and solve various problems in the process of machining the leading and trailing edges of aero-engine blades by manual grinding,EDM copying and electrolytic machining,a six-axis EDM envelope machining method was proposed to trim the leading and trailing edges of the blades.There would be several errors in the electrode manufacturing and installation process.In order to minimize the cost and develop a rationalized tolerance constraint,a second development of UG was carried out,and single source errors and 57combined source errors in 6 degrees of freedom directions were imposed on the existing electrode model according to 6 tolerance levels without considering the discharge gap and electrode loss.According to the engagement principle of the conjugate surface,the influence law of each source error on the final envelope processing error was analyzed,and the error sensitive factors that need to be strictly controlled in this new process were obtained.The results show that the single source errorsδ_(z)andδ_(C)have the error expansion multiplier K of 1.15 and 1.61,respectively,which have less influence on the envelope processing error;the combined source errorsδ_(xB)andδ_(yA)have the error expansion multiplier of 10.46 and 8.53,which have more influence on the envelope processing error and should be strictly controlled.