The reasonable determination of the processing plan of the small screw hole in the CNC machining center is a very key element for the processing of the screw hole. We proposed the following machining schemes for CNC machining of small screw holes.

1)  When machining the screw hole on the thin-wall deep cavity part, it is installed twice. Among them, when clamping the milling cavity, it is generally a clamping, and its cutting force is large, and the clamping force is large. The machining clamping of the screw hole is generally the second clamping, and the cutting force is weakened at this time, and the clamping force used is therefore reduced. And this can effectively reduce the deformation caused by the first assembly.

2)  When machining the screw hole on the thin-wall deep cavity parts, the support fixture can be used to clamp the larger cavity, which can effectively reduce the vibration generated by cutting. In this process, it is necessary to design the supporting milling fixture of the cavity, so as to effectively reduce the vibration generated during machining.

3)  When machining the screw hole on the thin-wall deep cavity parts, the tapping speed should also be appropriately reduced, which can effectively reduce the cutting force, thereby reducing the vibration that occurs during processing.

4)  When machining the screw hole on the thin-wall deep cavity parts, the spring clamp set should be used to clamp the tap, so that the coaxiality between the tap and the spindle can be improved.

5)  You can use the extrusion tap to tap, which can not only improve the strength of the tap, but also play a great role in improving the speed and efficiency of the tap.

6)  If the deep cavity thin-walled parts have a box body and a box cover, because the cover plate and the box body are often connected by countersunk screws when assembling, it is necessary to ensure that the threaded holes and countersunk holes remain coaxial. Therefore, after the processing of the small screw hole on the box body is completed, when the countersunk hole on the box cover is processed, the milling fixture is needed to ensure the position of the small screw hole on the box body.