Abstract: The manufacturing process of FPC reinforcement process, because the characteristICs of FPC are light/thin/short/SMAll, its manufacturing process is more complex and more refined than that of rigid PCB during production and processing, for example, the requirements for the reinforcement process of FPC flexible PCB and the selection of reinforcement materials are relatively strict.

The Flexible circuit board is characterized by being light, thin and short, so it is also the best choice for most intelligent electronic products. flexible circuit boards are also easy to be broken, broken, scarred and other operations during use, with low mechanical strength and easy to crack. Therefore, the purpose of bonding reinforcement materials is to strengthen the mechanical strength of flexible circuit boards and facilitate the surface mounting of parts, etc. There are many types of reinforcement films used for flexible circuit boards, depending on the different requirements of products, mainly including pet, pi, adhesive backing, metal or resin reinforcement boards, etc.

1、 Main flow of FPC reinforcement

production process flow: blanking (copper foil protective film reinforcement psa) → drilling (copper foil protective film reinforcement psa) → Black hole or pth → Dry film pasting → Film alignment → Exposure → Development → Copper electroplating → Dry film removal → ChEMIcal cleaning → Dry film pasting → Film alignment → Exposure → Development → Etching → Dry film removal → Brushing → Paste/lower protective film → Lamination → Reinforcement → Lamination → Hole punching → Text printing → Baking → Surface treatment → PSA pasting → Segmentation → Lead punching → Electrical inspection → Shape stamping → fqc (full inspection) → oqc → Packaging → Shipping

2、 Reinforcing and fitting

1. Hot pressing reinforcement: at a certain temperature, the heat hardening adhesive of the reinforcement film begins to melt, making the reinforcement film stick to the products, so that the reinforcement is positioned.

2. Pressure sensitive reinforcement: the reinforcement can be adhered to the products without heating.

3、 Reinforcement pressing

1. Hot pressing reinforcement: melt the heat hardening adhesive of the reinforcement film at high temperature, and use appropriate pressure or vacuum to make the reinforcement film closely fit on the FPC.

2. Pressure sensitivity reinforcement of flexible circuit board: no heating is required, and products are pressed by cold press

4、 Ripening

For hot pressing reinforcement: the pressure during pressing is small and the time is short. The reinforced thermosetting adhesive is not fully aged. It needs to be baked at high temperature for a long time to fully age the adhesive and increase the adhesion between the reinforcement and the product.

5、 Introduction to FPC equipment

1. Refrigerator: used to store the reinforcing film to be refrigerated

2. Pre laminating machine (c/f laminating machine): laminating hot pressing reinforcing film

3. Manual fitting fixture: fitting cold pressing reinforcing film

4. Vacuum machine: press the finished products with hot pressing reinforcement

5.80t fast press: press the pi thin hot pressing reinforcement and fitting products

7. Cold press: press the cold compressibility reinforcement

8. Oven: baking finished products with hot pressing reinforcement

6、 Introduction to Fixture for Flexible Circuit board

1. Pre sticking fixture:

2. Positioning pin:

7、 Reinforcing film

1. Reinforcing film: It is used to strengthen the mechanical strength of FPC, which is convenient for surface mounting operation. The common thickness is 5mil and 9mil

2. Adhesive: It is a heat hardening adhesive or pressure sensitive adhesive, and the thickness depends on customer requirements

3. Release paper: avoid foreign matters on the adhesive before pressing

4. Store the reinforcement film to be refrigerated according to the requirements on the material card

5. Refrigeration temperature: 1~9 ℃, shelf life of 3 months under refrigeration conditions

6. The flexible circuit board reinforcement materials shall not be stored for more than 8 hours at room temperature