Three principles of NUMERICAL control processing technology
1. The principle of maximum concentration of process and positioning at one time
Generally on nc machine tools, especially on the machining center processing parts, processes can be concentrated to the greatest extent, namely the parts in a clamping should as far as possible to complete the digit-controlled lathe processing most or all of the process, nc machining tend to process, can reduce the number of machine tools and workpiece clamping, reduce unnecessary positioning error and high productivity. For the hole processing with high coaxiality requirements, it should be installed after a sequence of continuous tool change to complete all the processing of the same axis hole system, and then process the holes in other positions to eliminate the impact of repeated positioning errors and improve the coaxiality of the hole system.
2. First, fine later.
In CNC machining, according to the parts of the processing accuracy, stiffness and deformation and other elements to divide the process, should follow the rough and finish processing is separated to divide the process, that is, the first rough machining is completed and then semi-finishing, finishing. For a machined surface, it should be finished in the order of roughing - semi-finishing - finishing. Rough machining should be in the guarantee of processing quality, tool durability and machine tool - fixture - tool - workpiece process system rigidity allowed under the conditions, give full play to the performance of machine tools and tool cutting performance, as far as possible to use a larger number of cutting to get finishing before the various parts of the allowance as uniform as possible processing status. The precision and surface quality of the parts are mainly guaranteed when finishing the saw industry, so the final contour of the parts should be continuously finished by the last knife. In order to ensure the processing quality, under normal circumstances, finishing allowance to stay 0.2-0.6mm is appropriate, coarse, finishing, the best between a period of time, in order to make the deformation of parts after rough processing is fully restored, and then finishing, in order to improve the processing accuracy of parts.
3. The principle of near before far, surface before hole
According to the processing part relative to the size of the distance from the knife point, in general, close to the knife point of the parts of the first processing, far from the knife point of the parts after processing, in order to shorten the tool moving distance, reduce empty travel time. For turning, it is also beneficial to maintain the rigidity of blank parts or semi-finished products and improve their cutting conditions. For the machining of both milling plane and boring parts, it can be carried out in the order of first milling plane and then boring. Because when milling plane cutting force is large, parts are prone to deformation, milling first after boring, so that it has a period of time to recover, to be restored to the deformation of boring, to ensure the accuracy of hole processing. Secondly, if the first boring after milling plane, hole mouth will produce burr, fly-edge, affect the hole assembly.