The CNC machining process of the lower cover of the gear box assembly

The material is made of 6063 grade aluminum alloy extruded profiles, which can be directly bought back in the market. Because the profiles are extruded under high pressure, the material is denser than aluminum alloy die-casting, and the internal defects of the material (such as sand holes, etc.) are less and the strength High, good cutting performance. In addition, 6063 grade aluminum alloy has better oxidation and coloring performance, so it is selected after comprehensive consideration. The cross section of the extruded profile has a variety of sizes. We choose one that is slightly larger than the cross section of the part. The length can be 5 parts to be sawed. An aluminum profile has 5 parts. If one thousand parts are produced, it will be sawed. More than two hundred materials. As shown in Figure 4.

2 The preliminary work of positioning and clamping processing needs to prepare a base plate. The base plate is clamped on the machine tool without moving, while the aluminum material is locked on the base plate by screws. The processing idea is: first one by one more than 200 pieces of aluminum A side All are processed, and then the B side is processed on the reverse side.

Since machining positioning and centering are performed on the bottom plate, the parallelism of each surface of the bottom plate and the flatness of the upper and lower bottom surfaces are very important. In order to ensure the processing requirements, the bottom plate is processed as follows

(1) The bottom plate is made of iron plate with a thickness of about 15mm.

(2) Use a grinder to grind the two large surfaces first, and place them on the machine for clamping.

3 The four-sided iron has straight edges and is used for centering to determine the processing origin.

(4) Write the drilling program, drill 4 positioning holes at both ends of the bottom plate, and then manually tap the screws (shown in the green part in Figure 5). The purpose of drilling several positioning holes is to quickly clamp and lock Workpiece. When processing the A surface feature, use the four screws of the bottom plate to lock the aluminum material (the purple part in Figure 6}. When processing the B surface feature, use the other 4 screw teeth. When processing the A surface, the hexagon socket screw The positioning requirements of the 4 screws are not high, and the 4 screws are used for locking and positioning. However, when processing 8 sides, they must coincide with the processing origin of A. At this time, the 4 screws are only used for locking and cannot be used for positioning

(The positioning method of side B is described in detail below).