双臂自适应夹具加工变形控制方法

在叶片加工过程中,由于叶片的薄壁和曲率多变特点,易受装夹、切削力和残余应力的影响而产生弯曲、扭转变形。针对该问题,本文提出了一种双臂自适应夹具加工变形控制方法,将加工过程中产生的变形逐层消除。首先,对叶片的变形成因进行分析;然后,通过对无应力装夹和加工应力释放原理进行研究,设计了一种可提供6个自由度的自适应装夹机构,并对该机构进行了工程设计和机构分析;最后,基于这种6自由度双臂自适应装夹机构,形成了本文提出的加工变形控制工艺,不需多次修复基准和更换机床,就可以逐层消除新产生的变形。实验结果表明,采用双臂夹具自适应加工变形控制方法,可以有效控制叶片加工过程中产生的变形,使叶片的轮廓误差降为原来的50%,提高了其加工精度。

A control method of machining distortion using adaptive fixture with dual-arm

Blade is easily affected by clamping, cutting force and residual stress which result in warp and torsion due to thin-walled and free surface of blade. In this paper, a new method for the control of machining distortion that eliminates surface errors by using an adaptive dual-arm fixture is presented. Firstly, the sources of distortion in different machining methods are discussed. Secondly, after the detailed analysis of unstressed fixing and stress releasing, the engineering design and mechanism analysis of the adaptive mechanism are shown. Finally, a control process of machining distortion is obtained based on the adaptive dual-arm fixture. Machining distortion can be eliminated without multiple repairing datum and changing machine. The experimental results show that the adaptive dual-arm fixture can effectively eliminate surface errors by 50% in machining, and the precision of test blade machined in this way is improved obviously.