There are often several surfaces to be machined on a CNC machined workpiece, and these surfaces not only have certain accuracy requirements of their own, but also certain positional requirements between the surfaces. In order to achieve these accuracy requirements, CNC machining of the surface of the order can not be arbitrarily arranged, but must follow certain principles, which is the selection and conversion of the positioning reference to determine the order of processing, as well as the former process for the subsequent process to prepare the principle of positioning reference. Next, the importance of CNC machining sequence are what aspects?
1, in the important surface processing before, the fine benchmark should be a rest, in order to help ensure that the important surface processing accuracy.
2、After the fine benchmark is machined, each major surface with high accuracy requirements should then be rough machined, semi-finish machined and finish machined. The surface with particularly high accuracy requirements also requires finishing.
3, as a fine reference surface should be processed at the beginning of the CNC machining process, because the subsequent processes to process other surfaces to use it to position. That is, “first benchmark after other”.
4, in the processing of fine reference surface, need to use the coarse reference positioning. In a single piece, small batch production, or even batch production, for complex shape or size of the castings and forgings, as well as the size of the larger error of the blank, before the machining process should first be arranged for the scribing process, in order to provide a corrective benchmark for fine benchmark processing.
5, for easy to appear scrap process, finishing and finishing processing can be appropriately placed in front, some minor small surface processing can be placed after.
CNC machining process not only to pay attention to the order also need to pay attention to the CNC processing stages of the division, how to do specifically?
When the quality of parts processing requirements are high, it is often impossible to use a process to meet the requirements, but to use several processes to gradually achieve the required processing quality. In order to ensure the quality of cnc machining parts and reasonable use of equipment, manpower, parts of the processing process is usually different by the nature of the process, can be divided into four stages; rough machining, semi-finishing, finishing and finishing machining.
The division of the cnc machining stages should be based on the quality requirements of the parts, structural characteristics and production programme flexible, should not be absolute. Machining quality requirements are not high, good tool stiffness, high accuracy of the blank, machining allowance is small, the production program is not large tools, can not be divided into processing stages. Good rigidity of heavy workpieces, due to the clamping and transport and time-consuming, but also often in a clamping to complete all rough and finish machining.
For not divided into processing stages of the workpiece, in order to reduce the rough machining of various deformation on the impact of processing quality, should be in the rough after the release of the stepping mechanism, parked for a period of time, so that the workpiece fully deformed, and then use a smaller stepping force to re-intensify, for finishing.