At present, machining operations, In the processing of some mechanical parts of the hole.
The hole below the diameter of the hole is larger than it.
The hole and its internal end face for the hole runout tolerance have higher requirements.
Such as the catheter hole here is 16 v240 cylinder head to beat the big hole and the face of higher tolerance requirements, and because of the catheter hole and it requires a higher seat hole.
So can only from the first top seat hole processing, processing catheter hole again, and as the big hole and inner face under the catheter hole in another process.
To ensure processing within a big hole and end face run-out tolerance with the catheter holes.
To design the high precision fixture, and more difficult to operate.
In addition, the rivet assembly and bolt connection assembly used in the automobile, aircraft and other products with complex structure, some of the rivet hole and screw hole can only be arranged in the structure of semi-closed or nearly closed state, the manual basic air drill cannot sink of rivet hole or screw hole head a conical sink hole implement positive treatment.
Solid carbide face milling cutter can only adopt the method of reverse cutting, and usually, the reverse cutting tool is more complex, need higher processing skills, which increases the difficulty of processing and efficiency.
When the conical sink hole processing quantity is large, the workers processing efficiency is very low.