How is the lamination of multi-layer FPC flexible circuit board completed, and what is the difference between it and traditional rigid PCB circuit board? The following is a brief introduction to the lamination technology of multilayer FPC flexible board.
Let’s talk about the lamination process of multilayer flexible PCB: lamination, mold opening, feeding, mold closing, pre-pressing, forming, cooling mold opening, blanking, inspection and next working procedure.
Matters needing attention and operation instructions when stacking:
A. prepare release film steel plate silica gel before production of circuit board, and clean the dust and sundries on the surface of steel plate silica gel release film with dust cloth or dust paper.
B. Open the size of the release film (500m*500m) and place it in the laminating area for later use. Every time the soft board is laminated for one cycle, 400 spare steel plates are needed, so that the production will not be broken.
C. During lamination operation, gloves should be worn with both hands or finger gloves with five fingers. It is forbidden to touch the soft board with bare hands.
D, when stacking plates, put steel plates, silica gel, release film, soft PCB and release film first.
Silica gel and steel plate. Stack 10 layers all the time (except for special requirements); The number of FPC boards placed on each layer is determined by the size of every 1PNL board (the distance from the board to the four sides of silica gel should be 7cm or more); When placing the boards, the FPC should be placed in the center of the silica gel as far as possible, and the spacing between each board is 2cm. The thickness of FPC placed in each layer should be consistent (for example, single panel should not be mixed with multilayer boards; Every opening, every floor should display the same pattern of FPC, and the position and sequence of the pattern should be roughly the same. When placing, the FPC should be covered with film or pasted with reinforcement face upwards. The release film should be flat and covered on the soft board, without wrinkles and folds. After the operation, lay the laminated FPC on the conveyor belt and send it to the next process. Flexible printed circuit board factory basically uses this method, such as commonly used FPC flexible flat cable and so on.
Pay attention to the following items when laminating flexible circuit boards:
Gloves or finger gloves must be worn during lamination operation, so as to prevent stratification caused by pollution on the board surface.
Before lamination, check whether the steel plate is uneven, whether the silica gel is damaged, cracked or honeyed, and whether the release film is stuck with garbage. Only the steel plate, silica gel and release film without the above defects can be used in production.
The position and graphics of FPC (flexible circuit board) should be consistent when stacking.
When releasing the release film, you must first confirm the front and back of the release film. Confirmation methods: 1. Draw a corner of the release film with an oil pen, and if the handwriting is clearly marked as the reverse, it is not clear as the front. 2. Touch the release film with white gloves, and the side that is smooth and logical is the front, and vice versa.
Operation and production process of lamination: film stripping-pretreatment-bonding-pressing-electroplating.
Lamination process: drilling-attaching BS film-over-molding-pressing base material-depositing Cu.
Every step of strict flexible circuit board manufacturers must be completed according to the regulations.
Basic structure of FPC
In recent years, with the widespread popularity of mobile products such as smart phones and tablet computers, flexible PCB boards, which were not recognized by too many people, have been adopted more and more, while many people don’t know much about the structure of FPC.
From the combination of flexible printed circuit board substrate and copper berth, it can be roughly divided into adhesive flexible circuit board and non-adhesive flexible circuit board.
First of all, talk about non-adhesive products. The price of non-adhesive FPC flexible board is much more expensive than that of adhesive material, mainly because the processing of non-adhesive substrate is difficult and complicated. However, as far as performance is concerned, the adhesive-free FPC is better than the adhesive products in terms of the bonding force between the copper foil and the substrate and the flatness of the pads, and its flexibility is also better than that of the adhesive products. Therefore, it is mainly used in some products that require high performance.
Although the flexible printed circuit board with adhesive is slightly inferior to the non-adhesive products in some aspects, its performance is not much different from that of the non-adhesive products because of its low price, and the general products are all competent, so most of the flexible printed circuit boards used in the market still have adhesive materials. We also mainly analyze the structure of FPC flexible printed circuit board with adhesive materials as an example.
Like rigid PCB, FPC flexible board can be divided into single-sided, double-sided and multi-layered flexible circuit boards.