Machining Error Compensation for Thin-Walled Surface Parts Based on On-Machine Measurement and NURBS Surface Reconstruction

To improve the machining accuracy of thin-walled curved surface parts, this paper proposes a machining error compensation method based on on-machine measurement (OMM) and Non-Uniform Rational B-Spline (NURBS) surface reconstruction. This method first employs a high-precision contact probe for on-machine measurement after semi-finishing the part, acquiring discrete point cloud data of the actual machined surface. The NURBS surface control points are fitted based on the measured data to reconstruct the machined surface. The machining error of the surface is obtained by calculating the distance between the machined surface and the design surface. A compensation surface and compensated machining toolpath are then generated based on a mirror compensation model. Finally, the machining errors before and after compensation for thin-walled curved surface parts were experimentally validated. Using this compensation method, the maximum value of the machining error was reduced from 0.2062mm to 0.1008mm, and the average absolute value of the machining error was reduced from 0.0610mm to 0.0191mm, while machining accuracy improved by 68.65%. It was verified that this method could effectively reduce machining errors. This method can be used to detect and compensate for machining errors in thin-walled curved surface parts, providing an effective technical solution for machining high-precision thin-walled curved surface parts.