Keyword: PCB copy board, circuit board inspection, PCB plating
In the PCB copy board O / S testing and AOI circuit board inspection when the outermost layer PCB copy board , masking the next discovery of a short circuit , we called filaments short , as short positions with visual looks a bit like a fine wire, crooked , sliced looks mainly copper , the copper surface and the normal long together, circuit board these shortcomings great harm.
If not resolved will have a direct impact on the overall quality of PCB copy board .
1.PCB copy board some filaments are not entirely caused by short circuit , possibly only after the customer causing a short circuit on the tin , so the O / S test is easy to leakage, flow to the hands of customers .
2.PCB copy board some very fine filaments , the test found that even after covering masking circuit , but not easy to find shortcomings repair staff positions beyond repair and scrapped circuit board.
Improvement for such shortcomings , many aspects may be necessary to proceed, mainly in :
1.PCB plating , plating bath time if there is a foreign body type filaments , PCB copy board in the electroplating process may be adsorbed onto the board , copper , tin is formed after the final circuit .
2 .also suggested that because of washed -producing bacteria circuit board, caused by bacteria .
3.also be caused by foreign objects into the process before the plating line .
Many PCB circuit board has such a problem.
The filaments have a variety of sources : First PCB copy board with ash brush roller when inside nylon material loss, caused after plating , Another is produced when drilling filaments, Another is electroplated adsorption . In the first case the needle can be used nylon brush, or to enhance high-pressure pump pressure , PCB copy board to strengthen the tank washing and filtration . The second is drilling adjustment . The third is circuit board the pollution of plating tank cleaning filtration problems . Finally, note that when the solder resist ink brush plate is the same attention. When the test pressure of such filaments can be used to interrupt . In my previous experience to see , PCB copy board plating occurs as relatively small, this part of the basic brush plate produce more, too much of this and drilling burrs are closely linked , drilling produce filaments fewer problems . In actual PCB copy board process will encounter many problems , I will introduce in the future eleven circuit board.
