CNC processing sequence arrangement

After selecting the cnc processing method and the dividing process, the main content of the process route is to arrange the order of these processing methods and processing steps reasonably. The cnc processing of the part usually includes a cutting process, a heat treatment process, and an auxiliary process (including surface treatment, cleaning, inspection, etc.). The order of these processes directly affects the processing quality, production efficiency and processing costs of the parts. Therefore, when designing the cnc processing route, the order of cutting, heat treatment and auxiliary processes should be arranged reasonably, and the connection problem between the processes should be solved.

Cnc processing steps:

(1) first coarse and fine

For example, in the order of roughing, semi-finishing, and finishing, the machining accuracy is gradually increased. The roughing will cut off most of the machining allowance on the surface of the workpiece (as shown in the cool line shown in Figure 2-4) in a short period of time. In this way, on the one hand, the metal removal rate is increased, and on the other hand, the uniformity requirement of the finishing car is satisfied. If the uniformity of the remaining amount after roughing can not meet the requirements of finishing, then a semi-finished car should be arranged to prepare for the finishing of the car. The finishing car must ensure the machining accuracy, and cut the contour of the part one by one according to the size of the drawing.

(2) First and then far

Under normal circumstances, the modern part of the cutting point is processed first, and the part of the cutting point is processed later to shorten the moving distance of the tool and reduce the idle travel time. For turning, the near-far sea is good for maintaining the rigidity of the blank or semi-finished product and improving its cutting conditions.
(3) Internal and external cross principle

For the parts that need to be machined on both the inner surface (inner cavity) and the outer surface, when the processing sequence is arranged, the inner and outer surfaces should be roughed first, and then the inner and outer surfaces should be finished. Do not machine a part of the surface (outer or inner surface) of the part and then machine the other surface (inner or outer surface).

(4) Foundation first principle

The surface used as a fine reference should be processed preferentially. This is because the more precise the surface of the positioning reference, the smaller the clamping error. For example, when machining a shaft part, the center hole is usually machined first, and the outer surface and the end surface are processed with the center hole as a fine reference.

(5) Principle of the first and second principles

The main working surface and the mounting base of the part should be machined first, so that the early detection of the main surface of the blank may cause modern defects. The secondary surface can be interspersed, placed on the main machined surface to a certain extent, and before final finishing.

(6) First face and back hole principle

The plane profile size of the box and bracket parts is large. Generally, the plane is first processed, and the holes and other dimensions are processed. In this way, the processing sequence is arranged, and on the one hand, the processed plane is positioned to be stable and reliable; on the other hand, it is easy to machine the hole in the processed plane, and the processing precision of the hole can be improved, especially when the hole is bored. Partial.