The function of the covering film, commonly known as coverlay, is to protect the flexible circuit board from the erosion of dust, moisture and chemicals and to reduce the influence of stress in the bending process, mainly playing an insulating role.
First, make preparations: check whether the soldering iron has electricity and clean the soldering iron slag, knife and pencil, and dust-free paper; Covering film material.
Bonding method of covering film:
1. Check whether the covering film and adhesive film have missing punching, missing drilling, multi drilling, punching, excessive burr of the covering film, etc., and clean the dust on the surface with an enveloping cleaner;
2. Tidy and clean the worktable, and put the covering film and electric soldering iron and other tools to be cleaned on the fixed position;
3. Check whether there is oxidation, debris, dust, etc. on the plate to be pasted. If any of the above bad items are found, rework or clean it before pasting;
4. Stick the covering film according to the process requirements and MI data, and align it strictly according to the "C" mark line on the board and the pad or alignment hole. For the board with pad, the exposed pad shall be evenly around when sticking the covering film.
5. The correct way to remove the covering film: put the covering film on the polishing table, with the release paper facing up and the covering film facing down, press one side of the covering film with one hand, and then slowly remove the release paper;
6. When the covering film is aligned with the "C" mark line of the plate and is correct, fix it with an electric soldering iron so that the covering film cannot shift or fall off. When the soldering iron is fixed, it cannot be burned on the product;
7. Single sided lamination: the pasted adhesive film plate is processed through the machine at a temperature of 160 ° -165 °. After cooling, tear off the adhesive film release paper, and conduct single-sided lamination and self inspection according to the alignment hole paste.
Precautions for covering film fitting:
1. Gloves and finger covers must be worn during the whole operation process, and only two thumbs can be exposed to prevent oxidation and finger prints on the board;
2. The process must be kept clean to prevent foreign matters from remaining on the board surface and inside the composite board;
3. Pay attention to inspection: the covering film is damaged, burred, and cannot be pasted. If there is any board wrinkle, board shrinkage, fog, scratch and other abnormalities, timely feedback and handling;
4. Do not wear bracelets, watches and other metal jewelry during working hours to avoid scratching the board surface;
5. When all circuit boards are electroplated with tin and gold, it is necessary to confirm that the plating edge should be left on the covering film;
6. Pay attention to the way when holding the soldering iron, and do not exceed the handle to avoid scalding;
The above is what Xiaobian introduced to you. If you need help, please call us!
