Evaluation of Thermal Error Compensation Strategies Regarding their Influence on Accuracy and Energy Efficiency of Machine Tools

Friction, electrical losses, cooling systems and ambient conditions influence the thermal field of machine tools and cause a significant amount of positioning inaccuracies and production errors. Compensation strategies aim to reduce the thermal error in machine tools. The global urgency for energy-efficient production also affects the selection of specific compensation strategies, especially since some of them consume significant amounts of energy while others are potential energy savers. As of today, there is no method to select the optimal compensation strategy for thermal errors in machine tools. The main reasons are that the quality of any compensation strategy depends heavily on the examined machine tool and its intended usage. Besides this, there are several, often conflicting assessment criteria.
This paper provides an overview of existing compensation strategies and presents an evaluation of their effect on the energy consumption. The investigated strategies comprise methods for reducing the heat losses, for decreasing the sensitivity of the tool center point to thermal influences, cooling strategies for removing heat from the machine tool, air conditioning and methods for controllable heat transfer and also various computational methods aimed at predicting and correcting the existing thermal positioning error in the machine tool control.
As an addition to previous research, the rating of thermal error compensation strategies was extended by their effect on energy efficiency. The authors demonstrate that accuracy and energy efficiency must be considered jointly for each individual machine tool and manufacturing task.