1.Positioning copper exposure -- This problem is relatively rare, and the generalreasons are as follows:

1)No oil on the screen (oil plugging when the screen is not clean);

2)Expose garbage;

3)There are blip blocking spots on the film (due to problems with the film itselfor the ink sticking during the exposure process of the film is not cleaned onthe film);

2.Non-positioned exposed copper

1)Expose garbage (no positioning);

2)Scratch welding;

3)Film adhesive oil;

Influenceof PCB copper leakage

Mainlyis the oxidation problem, generally in a short time will not have what theconsequences, a long time will rust hair green, rot away slowly.