Common questions and answers in CNC machining

What problems will you encounter in CNC machining? How to solve these problems? This is also a headache in CNC machining. The editor will solve this problem for everyone. The details are as follows. 1. How to divide the processing procedure? Answer: The division of NC machining processes can generally be done by the following methods, specifically: (1) Tool centralized ordering method is to divide processes according to the tools used, and use the same tool to process all the parts that can be completed on the part. Use the second knife and the third knife to complete other parts they can complete. This can reduce the number of tool changes, reduce idle time, and reduce unnecessary positioning errors. (2) Sorting method by processing parts For parts with a lot of processing content, the processing parts can be divided into several parts according to their structural characteristics, such as internal shape, shape, curved surface or plane. Generally, the plane and positioning surface are processed first, and then the hole is processed; the simple geometric shape is processed first, and then the complex geometric shape is processed; the parts with lower precision are processed first, and then the parts with higher precision requirements are processed. (3) For parts that are prone to processing deformation by the rough and finishing method of ordering, due to the deformation that may occur after roughing, the shape needs to be adjusted, so in general, all the rough and finishing processes must be separated. . Therefore, when dividing the process, it must be flexibly controlled according to the structure and manufacturability of the parts, the function of the machine tool, the number of parts CNC machining content, the number of installations and the production organization of the unit. It is also recommended to adopt the principle of process concentration or the principle of process dispersion, which should be determined according to the actual situation, but must strive to be reasonable. 2. What principles should be followed in the arrangement of the processing sequence? Answer: The arrangement of the processing sequence should be considered according to the structure of the part and the condition of the blank, as well as the needs of positioning and clamping. The important point is that the rigidity of the workpiece is not destroyed. The sequence should generally be carried out according to the following principles: (1) The processing of the previous process should not affect the positioning and clamping of the next process, and the processing of general machine tools should also be considered comprehensively. (2) The inner cavity is added, and then the outer shape is processed. (3) Use the same positioning, clamping method or the same tool processing process connection to reduce the number of repeated positioning, the number of tool changes and the number of times of moving the platen. (4) For the multiple procedures carried out in the same installation, the procedure should first be arranged with less rigid damage to the workpiece. 3. Which aspects should be paid attention to when determining the clamping method of the workpiece? Answer: The following four points should be paid attention to when determining the positioning datum and clamping plan, as follows: (1) Strive to unify the design, process, and programming calculation datum. (2) Minimize the number of clamping times, as far as possible to be able to process all the surfaces to be processed after one positioning. (3) Avoid using manual adjustment schemes. (4) The fixture should be opened smoothly, and its positioning and clamping mechanism should not affect the knife during processing (such as collision). When encountering such a situation, use a vise or add a base plate to draw a screw. 4. How to choose the knife path? The path of the tool is the path and direction of the tool relative to the workpiece in the index control process. The reasonable choice of the processing route is very important, because it is closely related to the processing accuracy and surface quality of the parts. In determining the path of the tool, the following points are mainly considered: (1) The machining accuracy requirements of the parts. (2) Convenient numerical calculation and reduce programming workload. (3) Seek a short processing route and reduce the time of empty tool to improve processing efficiency. (4) Try to reduce the number of blocks. (5) For the roughness requirements of the workpiece contour surface after processing, the final contour should be processed continuously with one pass. (6) The advance and retreat (cut-in and cut-out) route of the tool should also be carefully considered to minimize the tool stop at the contour (a sudden change in cutting force causes elastic deformation) and leave tool marks, and avoid being perpendicular to the contour surface Scratch the workpiece under the knife. (Picture/text http://www.wxdtc.com/)