Research on high precision reverse surface of fastener based on polynomial recursive fitting

In order to reverse the fastener, it is necessary to convert the fastener entity into three-dimensional digital model, and then send it to CAM soft system for subsequent editing to produce high-precision production mold. Based on the polynomial recursive fitting algorithm of closed curve, the extracted discrete point curve is decomposed, and the decomposed discrete curve is recursively fitted by quadratic polynomial to solve the polynomial recursive closed curve. The three-coordinate experiment results show that the detection results of each layer of the inner cavity surface are within 0.005 mm.