机床定位误差中的热误差分离与实验

Separation and Experiment of Thermal Error in Machine Tool Positioning Error

提出一种从机床定位误差数据中分离出热误差的新方法。设计了由双频激光干涉仪、温度传感标签与接收器等组成的热误差测试系统,可实现热误差温度信号的无线智能检测和热变形信号的非接触高精度采集;从机床冷态开始,来回循环测量定位误差并记录热敏测点温度值;对各循环内的前后测点定位偏差做插值、相减、平均等处理,再与冷态下的平均定位误差相减分离得到热误差。在2515龙门加工中心上进行了实验,数据处理不仅可得到定位偏差、重复精度、回程误差等6个几何精度指标,还分离出测量范围内各个测点的热误差,其最大值为9.67μm;最小二乘法建模结果表明热误差的建模精度在[-2.60μm-2.28μm]之间,建模精度平均值为0.73μm。

A method to separate thermal error from machine tool positioning error data has been presented.A thermal error testing system composed of a dual-frequency laser interferometer,a temperature sensing tag and a receiver is designed,which can real⁃ize the wireless intelligent detection of thermal error temperature signals and the non-contact high-precision acquisition of ther⁃mal deformation signals.Starting from the cold state of the machine tool,cycle back and forth to measure the positioning error and record the temperature value of the thermal sensing point.Interpolation,subtraction and averaging were performed for the po⁃sitioning errors of the front and rear measuring points in each cycle,and then the thermal errors were obtained by subtraction and separation of the mean positioning errors in the cold state.Experiments were carried out on 2515 gantry machining center,and the data were processed.Not only six geometric precision indexes such as positioning deviation,repetition accuracy,and back⁃haul error can be obtained,but also the maximum thermal error was calculated to be 9.67μm.The least-square method is adopt⁃ed to thermal error modeling,the results show that thermal error modeling precision is between[-2.60μm-2.28μm]and the aver⁃age modeling precision is 0.73μm.