Experimental Investigation of Passive Thermal Error Compensation Approach for Machine Tools

Conventional approaches to counteract thermal issues in machine tools often require a significant amount of electrical energy input, such as in active cooling systems. An energy-efficient way for reducing thermal errors is to use passive components that redistribute heat introduced by feed drives and other internal heat sources. On the one hand, latent heat storage units can be integrated into the machine to enhance the thermal stability within the phase transition temperature range of the underlying phase change material. By using latent heat storage units, the impact of highly time-varying heat flows on the thermal displacement of the tool center point can be reduced. On the other hand, passive heat-transfer devices such as heat pipes allow for an increased heat exchange within the machine tool or between the machine tool and the environment. Heat pipes exhibit a very high effective thermal heat conductivity and can be used to transfer heat from machine-internal heat sources to additionally integrated heat sinks. A compensation system is presented combining latent heat storage units and heat pipe systems. To evaluate the effect of the corresponding components on thermally induced displacements, experimental investigations of the system within a machine tool are conducted. By means of temperature and displacement measurements it is demonstrated that the proposed compensation approach allows for partial compensation of the thermal error of the machine tool.