Tool path transplantation method for adaptive machining of large-sized and thin-walled free form surface parts based on error distribution

For the machining of freeform surface parts with large size and thin walls, the actual shape of the blanks is always inconsistent with the desired shape, unexpected overcut or undercut will be introduced by using the tool paths generated according to the nominal part model. According to the online inspection results of large-sized and thin-walled freeform surface part, we found that the error distribution of the blank has different magnitude and form over the whole surface of the part. In this paper, the error distribution is mathematically defined based on online inspection data, and new tool paths adaptive to the actual shape of the workpiece are generated on the basis of the tool paths of nominal model, different tool path transplantation strategies are adopted according to the error distribution for different surface areas. A typical aircraft skin part with dimensions of 3867 mm x 1905 mm x 6 mm is used as a case to validate the proposed approach, the actual cutting experiment results show that the wall thickness error ranges from -0.089 mm to + 0.162 mm, and the shape error is within 0.46 mm, which can both meet the machining requirement of the aircraft skin parts.