CNC machining accuracy enhancement by tool path compensation method

The manufacturing community has been constantly pursuing product quality improvement. As people rely more and more upon computer numerically controlled (CNC) machines to improve flexibility and productivity, micron-level dimensional accuracy of parts produced on these machines is receiving increasing demand. A novel approach of error characterization, namely the Generic Geometry Generalization (3G) approach is proposed as a convenient method to realize tool path compensation for machined dimensional errors. The viability of this approach is examined by identifying repeatable error patterns from the machined test part of different shapes, and characterizing the relationship between the errors and the trajectory of the tool path. The design of the test parts follows the criteria of simplicity, consideration of machining operation characteristics and easy measurement. An illustrative example is used to demonstrate the design of test parts, the error analysis and generalization, and the predicting power of the proposed approach. It was demonstrated that approximately 4 times improvement for an ordinary CNC machine can be achieved