Error compensation in machine tools — a review

One of the major errors in machine tools namely geometric/kinematic errors was discussed at length in Part I of this paper. Here, in Part II, another major source of inaccuracy, namely thermal error that occurs due to extended usage of the machine is analysed. Continuous usage of a machine tool causes heat generation at the moving elements and this heat causes expansion of the various structural elements of the machine tool. It is this expansion of the structural linkages of the machine that leads to inaccuracy in the positioning of the tool. Such errors are called thermal errors and constitute a significant portion of the total error in a machine tool. Thus the overall volumetric error of a machine tool is not only dependent on errors due to the assembly and the specific kinematic structure of the machine but also on the thermal errors. In Part II of this paper, an attempt is made to review the work carried out over the last decade in the estimation and compensation of temperature dependent errors.