A Modification of Geometric Error Model of Five-axis Machine Tools with the Consideration of Workpiece Coordinate System

摘要

Five-axis machine tools, which combine three linear axes and two rotary axes, can control not only linear positions but also relative angle between a tool and the workpiece. It has been applied to complex surface workpiece machining among all fields of manufacturing, such as the impellers in aero industry. However, as the addition of the two rotary axes, there are more error sources in the five-axis machine tools than which in the traditional three-axis machine tools. According to ISO 230-1 standard, the definition of each error source and the evaluation methods of machine tool accuracy has been standardized. Especially, in the case of five-axis machine tools, the geometric errors are considered most by researchers and engineers. It is known that the geometric errors are the positional and orientation errors of the axis average line of rotary axes, which caused the relative offset and orientation of the rotational centers. Since the geometric errors significantly deteriorate the machining accuracy, it is essential to model the geometric error to improve the five-axis machining accuracies.