Guarantee of surface quality of CNC machining

The surface quality of the part generally refers to the physical and mechanical properties of the surface layer and the surface micro-geometric error (ie surface roughness). The surface roughness value is the main factor that directly affects the performance of the parts. In the process, we must take corresponding process measures to improve the surface quality of the parts.

() Determine the correct machining process plan 1. Correctly choose the cutting method. The surface roughness obtained by down milling and track milling will be different. When finishing, down milling should be used as much as possible to help improve the surface quality of the parts. When turning round steel parts, try to use the same tool to turn different outer circles, and use alkali to reduce tool marks. Generally speaking, it is necessary to avoid turning non-continuous surfaces. If there are grooves on the workpiece and other surfaces to be processed, the processing should be arranged after the external turning is completed. When turning and forming a revolving surface, attention should be paid to selecting the appropriate main and secondary deflection angles to avoid tool marks caused by interference of tools. When machining the arc surface of such parts, a smaller deflection angle should be taken, and the tool tip should be rounded, and the fillet radius should be smaller than the radius of the machined surface.

2. Reasonable design of cutting-in and cutting-out routes When machining parts on a CNC machine tool, in order to reduce the traces of the tool and ensure the quality of the contour surface, the cutting-in and cutting-out procedures of the tool should be carefully designed. The cutting point of the tool should be extended along the periphery of the part to ensure the smooth contour of the workpiece. If the tool cuts into the part directly and vertically along the part contour, it will leave obvious tool marks on the shape of the part. Therefore, the tool should cut in and out along the normal line of the part contour. Avoid feed pause during contour processing, otherwise due to cutting Changes in force also produce knife marks. First of all, the cutting process of the tool generally requires a smaller feed rate. In order to improve the cutting efficiency, when cutting in, slowly enter the other cutting layer from one cutting layer, so as to ensure a constant feed rate. Secondly, try to maintain a stable cutting parameters, including the consistency of cutting speed, feed and depth of cut. Finally, it is necessary to improve the forming accuracy of the blank as much as possible to make the machining allowance of each surface uniform. In addition, if the same processing surface is processed twice, try to make the direction of the tool motion path consistent, so as to avoid any requirements such as collisions.