精密数控机床多主轴系统热平衡试验

对现有的精密数控机床主轴系统进行常规工况实验和空运转实验,提出一种数控机床热平衡试验方法,通过该实验方法可以获得数控机床主轴系统的热敏感点、温度场数据和热位移场数据以及热平衡时间等热态特性,以校验理论仿真分析,并建立误差模型,从而实现对主轴系统热特性的快速校核与加工误差补偿.在具有3个独立磨头主轴系统的直线滚动导轨精密曲面成形数控磨床上,开展多主轴系统热平衡试验方法的具体案例研究,获得了其中两个理论上相同的立式磨头的主轴系统温升变化曲线、热变形变化曲线和热平衡时间等不同的热态特性,论证了多主轴热平衡实验对于消除多主轴机床差异性上的重要性,弥补了多轴系统热态特性分析在理论上分析的不足.通过将热平衡试验获得多主轴系统的热态特性结果用于指导热误差补偿工作,减小了机床热误差控制及补偿难度,提高了机床加工直线导轨曲面精度与工作效率.

Thermal equilibrium test for multi spindle system of precision CNC machine tool

Based on regular working condition experiment and idle running experiment, a thermal equilibrium test method for computer numerical control (CNC) machine tool was proposed,which can be used to obtain the thermal characteristics of spindle system, such as the thermal sensitive points, the data of temperature field and thermal-displacement field and so on. And the calculation method of thermal equilibrium time was presented. In addition, the test method can verify the theoretical simulation and analysis, and establish the error model, so as to realize the fast verification of thermal characteristics and compensation of thermal error for spindle system. Taking a precision curved surface linear rolling guide CNC forming grinding machine tool which has three independent spindle systems as an example, the multi-spindle system thermal equilibrium test was carried out in real working condition. Through the test, the thermal characteristics of two vertical spindles were obtained, i.e. temperature curves, thermal curves and thermal equilibrium time, which were different between each other but the same in theory. Thus, thermal equilibrium test method can be used to explain the significance for eliminating the difference between multi-spindle system, and make up the lack of pure theoretical analysis and simulation. The thermal characteristics of multi-spindle system which are obtained from the test can be used to guide thermal error compensation work and reduce the compensation difficulty. The proposed method improves the machining precision and the working efficiency．