Modeling approach of regression orthogonal experiment design for the thermal error compensation of a CNC turning center

Thermally induced errors can account for as much as 70% of the dimensional errors of a workpiece. Accurate modeling of errors is an essential part of error compensation. Based on analyzing the existing approaches of thermal error modeling for machine tools, a new approach of regression orthogonal design is proposed, which combines statistical theory with machine structures, surrounding conditions, engineering judgements, and experience in modeling. A whole computation and analysis procedure is given. The model obtained from this method is more robust and practical than those that obtained from the method that depends completely on the modeling data. More than 100 applications of a CNC turning center with only one thermal error model are given. The cutting diameter variation reduces from more than 35 to about 12 μm with orthogonal regression modeling and compensation of thermal error.