CNC machining sequence arrangement

In the selection of CNC processing methods, after the division of the process, the main content of the process line is to arrange these processing methods and processing sequence. CNC machining process of parts usually includes cutting process, heat treatment process and auxiliary process (including surface treatment, cleaning and inspection, etc.). The sequence of these processes directly affects the processing quality, production efficiency and processing cost of parts. Therefore, when designing CNC machining process route, the order of cutting, heat treatment and auxiliary working procedure should be reasonably arranged, and the connection problem between working procedure should be solved.

CNC processing process arrangement:

(1) Rough before fine

For example, according to the rough car - semi - fine car - fine car order, gradually improve the machining accuracy. The rough lathe will cut off most of the machining allowance on the workpiece surface (as shown in FIG. 2-4) in a relatively short time. On the one hand, the metal cutting rate is improved, and on the other hand, the allowance uniformity of finishing car is satisfied. If the uniformity of the margin left after the coarse car can not meet the requirements of finishing, it is necessary to arrange half fine car, in order to prepare for fine car. Fine car to ensure the machining accuracy, according to the size of the drawing cut out the outline of the parts.

(2) Near first, far later

In general, from the modern part of the knife point first processing, from the point of the knife after processing, in order to shorten the tool moving distance, reduce the empty travel time. For turning, cutting conditions can be improved by keeping the rigidity of the blank or semi-finished product in the open sea.

(3) Internal and external cross principle

For both the inner surface (inner cavity) and the outer surface of the parts need to be machined, arrange the processing sequence, should be roughed on the inner and outer surface first, then the inner and outer surface finishing. Must not be part of the parts on the surface (outer surface or inner surface) after processing, and then processing other surfaces (inner surface or outer surface).

(4) Base antecedent principle

Priority should be given to finishing surfaces used as finishing reference. This is because the more accurate the surface of the positioning datum, the smaller the clamping error. For example, axis parts processing, usually first processing center hole, and then the center hole as a fine benchmark processing outer surface and end face.

(5) First, second

The main working surface of the parts should be processed first, and the base surface should be assembled, so as to find the modern defects on the main surface of the blank as early as possible. The secondary surface can be interspersed, after the main surface machining to a certain extent, before the final finishing.

(6) Face before hole principle

Box, bracket type parts of the plane outline size is large, generally processing plane first, then processing holes and other sizes. This arrangement of processing order, on the one hand, with processed plane positioning, stable and reliable; On the other hand, it is easy to process holes on the processed plane, and can improve the machining accuracy of holes, especially when drilling can be easy to deviate the axis of holes.