Therefore, generally, the roll covering film is sealed in polyethylene plastic bags. After taking it out of the cold storage, the sealing bag should not be opened immediately, but should be placed in the bag for several hours. When the temperature reaches room temperature, the covering film can be taken out from the sealing bag for processing.
The opening window of the covering film uses the NC drilling and milling machine or punch. The rotation speed of the NC drilling and milling can not be too large. Such operation cost is high, and this method is generally not used in mass production. 10 ~ 20 covering films with release paper shall be overlapped together and fixed with upper and lower cover plates before processing. Semi cured adhesive is easy to adhere to the drill bit, resulting in poor quality. Therefore, it should be inspected more frequently than when drilling copper foil plate, and the debris generated during drilling should be removed. A simple die can be used when processing the window of the covering film with the punching method, and the punching die is used for the processing of batch holes with a diameter of less than 3mm. When the hole of the window is large, the die is used, and the small and medium-sized batch of small holes are processed by NC drilling and die, and the covering film is processed
After removing the release film from the covering film with the window hole, stick it on the substrate with the circuit etched. Before lamination, clean the circuit surface to remove surface pollution and oxidation. Chemical methods for surface cleaning. After removing the release film, there are many holes of various shapes on the covering film, which completely becomes a film without framework, which is particularly difficult to operate. It is not easy to overlap and align the positioning hole with the position on the line. At present, factories in mass production still rely on manual alignment and lamination. Operators first accurately locate the covering film window hole and the connecting plate and terminal of the line pattern, and then temporarily fix it after confirmation. In fact, if the size of either side of the flexible printed board or covering film changes, it cannot be accurately positioned. If conditions permit, the covering film can be divided into several pieces before lamination positioning. If the covering film is forcibly stretched for alignment, it will cause more uneven film and greater change in size, which is an important reason for wrinkles in plate making.
Electric soldering iron or simple pressing can be used to fix the covering film temporarily. This is a process that completely depends on manual operation. In order to improve production efficiency, various factories have thought of many ways.
