In order to improve our work efficiency, we often carry out CNC processing, we are familiar with it. Pay attention to details when processing to avoid problems. Today, I’d like to discuss the cover parts of CNC machining process with you
- Process analysis of parts
The material of cover plate is cast iron, and the blank is casting. The cover plate needs to be processed for the plane, hole and thread are concentrated on a, B surface, the four sides of the edge do not need to be processed, the highest accuracy should reach it7 level. Then we can take the A-side as the positioning reference, and process it in the previous process. Select the B-side and the hole on the B-side to process on the machining center.
- Design process
(1) Select processing method
Rough milling can be used for surface B_ Finish milling: the dimension accuracy of Φ 60h7 hole is it7, The roughness is ra0.8um, and the blank hole has been cast, so rough boring and semi precision boring can be carried out+ Fine boring: the dimension accuracy of Φ 12h8 hole is required to be grade it8, and the roughness is ra0.8um. In order to prevent the drilling deviation, we can drill the center hole, drill the hole, enlarge the hole, ream the hole; when the thread hole is between M6 and M20, we can drill the bottom hole first and then tap the thread.
(2) Determine the processing sequence
In order to reduce the frequency of tool change and according to the principle of rough before finish and face to hole, the processing route is as follows: rough and finish milling B surface – coarse, semi finish, finish boring Φ 60h7 – drilling the center hole of each smooth hole and threaded hole – drilling, expanding 4 × Φ 2h8 hole – countersinking 4 × Φ 16 hole – twisting 4 × Φ 12h8 hole – M16 screw hole, drilling bottom hole, chamfering and tapping.
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