For multilayer boards, the middle layer can not be directly scanned out, to copy the multilayer board must be multi-layer grinding out, so copy multilayer board must be scrapped a PCB board.

The best way to use the current method is to use a good grinder and manual grinding with yarn paper, the latter method is the lowest cost of a method, sandpaper is available anywhere on the market to buy ordinary sandpaper, remember to coarse sandpaper, fine sandpaper is difficult to grind.

The method is very simple, the PCB board according to the level of force with sandpaper grinding, if there is a large piece of copper skin available pliers can be pulled off directly, or with a few flat frustration on the difficult to grind off, and then switch to sandpaper and then grinding.

Grinding board in fact, there is no technical content, purely empirical things, grinding a multi-layer circuit board will understand.