What are the special process holes in making PCB boards2020-03-28
1. Counterbored hole — The transition between the hole wall at the outermost / maximum hole diameter and the hole wall at the smallest hole is parallel to the pcb surface, and the part connecting the large and small holes is a plane, not an inclined plane.
The connecting part of the small and large holes is an inclined plane, not a plane. Note the control with angle (0-180 degrees)
2. Countersunk holes — Funnel holes, except that the top of the screws for installation are all on the pcb surface. The connecting part of the small and large holes is an inclined plane, not a plane.
3. Flare hole-similar to countersunk hole
4. Crimp hole — There is no change in the hole diameter, but the hole diameter tolerance is generally +/- 2mil, which is very strict. The pins of the plug-in generally do not need to be soldered. Common crimp holes are copper plated
Plug-in hole. Generally, more countersinks are used.
The machining methods of the countersink include drilling and countersinking. The countersink is divided into flat bottom countersink and cone countersink.
No matter what kind of countersink, you must first drill the main through hole with a drill, and then select different tools for countersinking according to the shape of the countersink. Flat bottom countersinking requires drilling
On the basis, the countersink is milled by an end mill. Taper countersinking requires countersinking of the drilled hole with a larger drill. When sinking holes, ensure that the workpiece is positioned at one time, and ensure the holes and sinkers