1. PCB short circuit caused by tin running 1. Tin running caused by improper operation in the film withdrawal liquid medicine cylinder;
2. The plates that have been removed are superimposed together to cause running tin.
2. PCB short circuit caused by uncleanness of etching 1. The quality of etching liquid parameter control directly affects the etching quality.
Common obstacle factors of PCB copying, 3. Visible PCB micro-short circuit 1. Line micro-short circuit caused by scratch of Myra film on exposure machine;
2. The line caused by the glass scratch on the exposure plate is slightly short-circuited.
Four, clip film PCB short circuit 1, anti-coating layer is too thin, electroplating because the coating exceeds the film thickness, forming clip film, especially the smaller the line spacing, the easier it is to cause clip film Short Circuit.
2. The pattern distribution of the plate is uneven. In the process of pattern electroplating, the isolated lines are short-circuited due to the high potential and the coating exceeds the film thickness.
Five, invisible PCB micro short circuit, invisible micro short circuit for our company, is the longest and once the most difficult problem to solve, in the test of the finished Board with problems, about 50% is a problem of this kind of micro-short circuit. The main reason is that there are wires or metal particles that cannot be seen by naked eyes in the line spacing.
Six, the fixed position PCB short circuit, the main reason is that the film line is scratched or the coated screen plate is blocked by garbage, and the coated anti-coating fixed position exposed copper causes short circuit.
Seven, scratch PCB short circuit 1, scratch after coating wet film, improper operation during alignment causes film surface scratch.
2. The exit of the developer is too busy to cause a collision between the board and the board.
3. Improper plate taking during electroplating, improper operation during upper splint, improper operation during manual line pre-treatment of the plate, etc. cause scratches.
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