Common Problems and Solutions for Dry Film pasting during PCB Manufacturing process

With the continuous development of the electronics industry and the continuous upgrading of products, in order to save board space, many boards have been designed with very fine wires. The previous wet film manufacturing process can no longer meet the current graphics transfer process, and nowadays, fine wires are usually produced with dry film process, so what problems do we have in the PCB process of filming, China PCB manufacturer SYS Tech introduce to you as below. 

Summary of common problems and solutions for PCB paste dry film

(1) Air bubbles appear between the dry film and the surface of the copper foil

Problem: Choosing flat copper foil is the key to ensuring no bubbles.

Solution: Increase the pressure of the PCB film, and handle the CCL lightly.

Problem: The surface of the heat press roller is not flat, there are pits and the film is dirty.

Solution: Regularly check and protect the flatness of the surface of the heat press roller.

Problem: The temperature of the PCB film is too high, causing some contact materials to produce wrinkles due to temperature differences.

Solution: Reduce the temperature of the PCB film.

(2) The dry film is not firmly attached to the copper foil

Problem: The surface of the copper foil is not properly cleaned, and the direct operation will leave oil stains or oxide layers.

Solution: Wear gloves to conduct PCB cleaning.

Problem: The quality of the dry film solvent is not up to standard or has expired.

Solution: The PCB manufacturer should choose high-quality dry film and check the shelf life of the dry film regularly.

Problem: transfer speed is fast, while the PCB film temperature is low.

Solution: Change the PCB filming speed and PCB filming temperature.

Problem: The humidity in the processing environment is too high, which leads to a prolonged dry film bonding time.

Solution: Keep the relative humidity of the production environment at 50%.

(3) Dry film wrinkles

Solution: Once contact occurs, it should be dealt with in time.

Problem: The board is overheated before the PCB filming.

Solution: The preheating temperature of the board should not be too high.

(4) Glue remains

Solution: Replace the dry film.

Problem: The exposure time is too long.

Solution: Have an understanding of the materials used and carry out a reasonable exposure time.

Problem: the developer is ineffective.

Solution: Change the developer.