基于转速和累积热误差的主轴补偿模型

Spindle Compensation Modeling Based on Speed and Cumulative Thermal Error

当前基于温度或转速的热补偿方法受限于数控系统或模型自身的局限性,在分析电主轴热伸长变化率的影响因素的基础上,提出一种基于转速和累积热误差的主轴补偿建模方法。基于某立式加工中心主轴,设计了包含启动、升速、降速、停机多种变转速工况的转速-热伸长实验,由实验数据分别建立自然指数函数预测模型和累积热伸长预测模型,并对比两种模型在设计工况的预测效果;针对主轴的累积热误差补偿模型,分别开展设计转速、单转速和随机变转速3种工况下的补偿验证实验。结果表明,3种工况下,主轴刀尖热伸长经基于累积热伸长的补偿模型补偿后,至少降低69%。这种方法成本低廉,补偿效果明显,且通用性良好,对热补偿方法的推广应用具有重要意义。

At present,the temperature or the speed based thermal error compensation methods are limited to CNC system and the model itself.The factors affecting the change rate of thermal error of a motorized spindle are analyzed,and a compensation modeling method based on rotating speed and cumulative thermal error is proposed.A thermal error measurement is conducted on the spindle of a vertical machining center under designed running speeds,including start-up,increase,decrease,shutdown and random speeds.Based on the measured data,the thermal prediction models based on natural index function and cumulative thermal error are established respectively,and the predicting effects of the two models under design conditions are compared.Focused on the cumulative thermal compensation model,three verification experiments are carried out under designed speed,single constant speed and random speeds respectively.The results show that under all three running conditions,the thermal error of the tool-tip of the spindle is reduced by at least 69%after being compensated.This proposed method has low cost,obvious compensation effect and good universality,which is of great significance to the popularization and application of thermal compensation method.