1. The selection principle of starting point and return point. In the same program, the starting point and return point should be the same. If the processing of a part requires several programs, the starting point and return point of these programs should also be exactly the same, so as to avoid causing trouble in processing operation. The coordinate values of the starting point and the return point should also be set to zero for both X and Y values, which makes the operation convenient.
2. The principle of selecting the cut in point is to prevent the tool from being damaged during the process of feeding or cutting the surface. Generally speaking, for rough machining, the highest corner in the surface is selected as the entry point of the surface. Because the cutting allowance at this point is small, it is not easy to damage the tool during feeding. For finish machining, select a corner with gentle curvature in the surface as the entry point of the surface. Because at this point, the bending moment of the tool is small, and it is not easy to break the tool.
3. The principle of cutting point selection mainly considers that the surface can be processed continuously and completely, and the non cutting processing time between surface and surface processing is as short as possible, and the tool change is convenient, so as to improve the effective working time of the machine tool. For the machined surface is an open surface, two corners of the surface can be used as the cut-out point. According to one of the above principles: if the machined surface is a closed surface, only one corner of the surface is the cut-out point, and the system generally determines it automatically during automatic programming.
