Global Offset Compensation for CNC Machine Tools Based on Workpiece Errors

Machine tool accuracy and repeatability is one of the most important considerations for manufacturing parts with the required quality for consistent performance in their assemblies. One of the most challenging areas has been the ability to quickly identify and evaluate the quasi-static and dynamic machine errors and apply the corresponding error models to compensate. Because there are many challenges associated with some methods, including the cost in design, analysis and control of precision machine tools, the compensation method has been the most effective approach to control part quality. This paper presents the development of a Global Offset compensation method utilizing the measurements of machined part(s). The Global Offset for a machine tool is estimated through a model while utilizing the computed deviation between the measured and nominal dimensions of the part. Examples are provided to demonstrate the capabilities of this new method.