With the rapid development of the PCB industry, PCB is gradually moving towards the direction of high-precision thin lines, small apertures, and high aspect ratios (6:1-10:1). The hole copper requirements are 20-25Um, and the DF line spacing is less than 4mil. Generally, PCB production companies have problems with electroplating film. The film clip will cause a direct short circuit, which will affect the yield rate of the PCB board through the AOI inspection. Serious film clip or too many points can not be repaired directly lead to scrap.

Principle analysis of PCB sandwich film
① The copper thickness of the pattern plating circuit is greater than the thickness of the dry film, which will cause film clamping. (The thickness of the dry film used by the general PCB factory is 1.4mil)
② The thickness of copper and tin of the pattern plating circuit exceeds the thickness of the dry film, which may cause film clamping.

Analysis of the causes of pinching
①The pattern plating current density is large, and the copper plating is too thick.
②There is no edge strip at both ends of the fly bus, and the high current area is coated with a thick film.
③The AC adapter has a larger current than the actual production board set current.
④C/S side and S/S side are reversed.
⑤The pitch is too small for board clamping film with 2.5-3.5mil pitch.
⑥The current distribution is uneven, and the copper plating cylinder has not cleaned the anode for a long time.
⑦Wrong input current (input the wrong model or input the wrong area of the board)
⑧The protection current time of the PCB board in the copper cylinder is too long.
⑨The layout design of the project is unreasonable, and the effective electroplating area of the graphics provided by the project is incorrect.
⑩The line gap of PCB board is too small, and the circuit pattern of high-difficulty board is easy to clip film.