When machining precision round parts, the most commonly used mechanical equipment in mechanical processing plants are CNC lathes. CNC lathes turn parts with high efficiency, high machining accuracy, complex contours, and a qualitative leap compared with ordinary ones lathe machining. However, the layout of the process is very important when turning on a CNC lathe. We have encountered the same machine tools and equipment, processing the same products, but the quality of the processed products is very different due to the difference in processing technology.
The ideal processing program should ensure that qualified workpieces conforming to the drawings are processed and enable the functions of the CNC machine tool to be reasonably applied and fully utilized. CNC machine tools are high-efficiency automation equipment, and their efficiency is 2 to 3 times higher than that of standard machine tools. To fully play this feature of CNC machine tools, performing process analysis on the workpiece before programming and choosing an economical and reasonable process plan according to specific conditions. Inadequate consideration of the CNC machining process is an important factor affecting machining quality, production efficiency, and processing cost of CNC machine tools.
Processing parts on CNC machine tools is relatively concentrated in the process. All processes should be completed as much as possible in one clamping. There are two common process division principles:
Numerical control machining has the conditions of concentration of working procedures, and rough and finishing machining are often completed in one clamping to ensure the machining accuracy of the parts. When thermal deformation and cutting force deformation have a greater impact on the machining accuracy of parts, rough and finish machining should be carried out separately.
In CNC machining, to reduce the number of tool changes and save tool change time, we should complete all the parts that need to be processed with the same tool and then change to another tool to process other parts. At the same time, reduce the idle stroke as much as possible. When processing multiple parts of the workpiece with the same tool, the shortest route should be used to reach each processing part.
In actual production, CNC machining often divides processes according to tools or machined surfaces.
In NC machining, the NC program should describe the motion path of the tool relative to the workpiece. In CNC turning, the formation of the workpiece surface depends on the position and shape of the envelope of the moving blade. Still, only the trajectory of a selected point on the tool system needs to be described in programming. The tool location point of the tool is the point selected on the tool that represents the tool's location during programming, and the processing path described by the program is the motion path of this point.
THEORETICALLY, in CNC turning, any point on the tool can be selected as the tool location point. Still, to facilitate programming and ensure machining accuracy, selecting the tool location point has certain requirements and skills. In CNC machining, the selection of tool location points generally follows the following rules: the end mill should be the intersection of the tool axis and the bottom of the tool; the ball end mill is the center of the ball; the drill should be the drill tip; the turning tool should be imaginary Attention should be paid to the tool nose or the arc center of the tool nose and the tool position point when selecting.