FPC circuit board covering film to open the window processing, but removed from the cold storage can not be processed immediately, especially when the ambient temperature is high and the

temperature difference is large, the surface will condenses water, when the base film is polyimide, will absorb moisture in a short time, will have an impact on the post-process. Therefore, the general

rolled covering film is sealed in a polyethylene plastic bag, and the sealed bag should not be opened immediately after being removed from the refrigerator, but should be placed in the bag for several

hours, when the temperature reaches room temperature, the covering film can be removed from the sealed bag for processing.

The use of CNC drilling and milling machine or punch, CNC drilling and milling rotation speed can not be too large, such high operating costs, mass production generally do not use this method.

Overlap 10 to 20 sheets of cover film with release paper and fix them with upper and lower cover pads before processing. Semi-cured adhesives tend to adhere to the drill bit, resulting in poor

quality. Therefore, it should be inspected more frequently than when drilling copper foil plates, and the debris generated during drilling should be swept away. A simple punching die can be used to

process the window covered with film by punching, and the processing of batch holes with a diameter of less than 3mm uses punching dies. When the hole of the window is large, the hole of small

and medium-sized batch is processed by CNC drilling and punching, and the processing of covering film is carried out.

After removing the release film from the window hole, paste it on the substrate of the etched circuit. Before laminating, the surface of the line should be cleaned to remove surface contamination and

oxidation. Surface cleaning by chemical methods. After removing the release film, there are many holes of various shapes on the covering film, completely becoming a film without a skeleton, which

is particularly difficult to operate, that is, the use of positioning holes to overlap with the position on the line is not an easy thing. At present, the mass production plants still rely on manual stacking,

the operator first covers the film window hole and the connection disk and terminal of the line graphics for accurate positioning, and then temporarily fixed after confirmation. In fact, if the size of

the flexible printed board or covering film changes, it can not be accurately positioned. If conditions permit, the covering film can be divided into several pieces, and then the lamination positioning.

If the covering film is forced to stretch for alignment, it will cause the film to be more uneven, so that the size of the greater change, which is an important reason for the wrinkle of the plate.

Temporarily fixed covering film can use electric soldering iron or do simple pressing, which is completely rely on manual operation of the process, in order to improve production efficiency, each

factory has thought of a lot of ways.