基于热变形临界点的数控机床光栅系统优化

为了研究引起机床热变形误差的各种热误差之间的相互影响，应用热变形临界点原理，对环境温度变化作用下 的机床机座热变形进行有限元数值模拟，确定机床机座的热变形临界点。利用有限元分析得到的机床机座热变形临界 点对光栅在机床机座上的固定方式进行优化分析，结果显示：光栅系统零点漂移量从0. 138 28 mm减小到0.065 50 mm， 而且机床机座的热变形将减小对整体光栅测量系统产生的影响，确定了固定方式的优化方向。同时应用形体热变形理 论，对优化固定方式后的光栅系统零点热误差和示值热误差位置进行精确建模，用于后续的数控机床综合误差补偿。文 中的研究为优化光栅在机床座上的固定方式提供一种新的方法。

Optimization of CNC Grating Fixed System Based on Thermal Deformation Critical Point Theory

In order to study the interaction between the thermal deformation error caused by the thermal error of machinetool. and by using thermal deformation critical point theory, the finite element numerical simulation of the thermaldeformation was carried out under the effect of variable ambient temperature. The thermal deformation of the machinewas calculated. The fixed manner of the grating on the machine was optimized by using the finite element analysis toobtain the thermal deformation critical point. The results show that zero drift value of grating system reduces from0. 138 28 mm t0 0. 065 50 mm. and the thermal deformation of the machine base has not an impact on the overall gratingmeasurement system. Meanwhile with the application of thermal deformation form theory, the precise modeling of zerothermal error and indication position error of the grating measurement systems was rebuilt for subsequent comprehensiveerror compensation of CNC machine. It provides a new method to optimize the grating fixed manner on the machine base.