Effective Measurement Method of Thermal Deformation of Machine Tools Caused by Linear Axis Motion

The spindles speed and feed rate of machine tools increase greatly to realize high-productivity with high accuracy. This leads to exceeding increase in heat generation and then the thermal deformation of the machine tools become serious problems. Therefore it makes necessary to measure and evaluate the thermal deformation. With these points as background, measuring methods for thermal deformation of machine tools were standardized in the international standard ISO 230-3 in March 20011). In this standard, the measurement methods of thermal deformation caused by environmental temperature variation, spindle rotation and linear axis motion were provided. For measuring thermal deformation caused by environmental temperature variation and spindle rotation, the methods to measure simultaneously five degrees of freedom components of the thermal deformation are specified in the standard. In this standard, the measurement method proposed by us for high-speed spindle is adopted as a recommended method2). In addition, we have proposed more effective evaluation method with our method3). On the other hand, in ISO, for measuring thermal deformation caused by linear axis motion, the only thermal deviation in positioning direction is measured. However, it is pointed out that the thermal deviations in other five directions also occurs and influence on the machining accuracy4). Then many measurement and compensating methods have been studied5,6). However, there are no simple and effective measurement methods for measuring the thermal deformations with linear axis motion. Therefore, in this paper, we propose a new measurement method to measure simultaneously six degrees of freedom components of the thermal deviation caused by linear axis motion in machine tools and shows its effectiveness.