Film capacitor manufacturing process and requirements

The film capacitor is a capacitor formed by winding a metal foil as an electrode and a plastic film such as polyethylene, polypropylene, polystyrene, or polycarbonate, which are stacked from both ends and wound into a cylindrical shape. But what is its production process? What are the requirements when making?

1. Film cutting: According to the product design capacity, the metal foil is cut with a film cutting machine to the required design width. No burrs are required during cutting, and the appearance is free from dirt and wrinkles.

2. Winding: According to the requirements of the process, the needle core and the metal film are selected and wound into a core by a winding machine. The film capacitor capacity is required to meet the design requirements, the core end surface is flat, the film is clean and the tension is moderate, and the film cannot be scratched.

3. Hot pressing: According to the requirements of the process, select the appropriate hot pressing parameters (pressure, temperature, time) on the hot press to flatten the core. It is required that the core cannot be loosened when the external force is slightly applied, and the film cannot be delaminated.

4. Taping: According to the requirements of the process, select the appropriate adhesive tape and weave the core into a roll. It is required that the adhesive tape has good adhesiveness, and the adhesive tape cannot cover the end face of the core.

5. Gold spraying: spray metal layers on the two end faces of the core. According to the requirements of the process, choose the spraying distance, air pressure, and wire speed. Requires the thickness and adhesion of the sprayed metal to meet the requirements.

6. Trimming: Remove the braid after spraying gold, and use a roller machine to remove the remaining edges after spraying gold and the excess metal dust adhered to the surface of the core. Refer to the process requirements for piping time and speed. It is required that there is no excess metal edge on the end surface of the core and no metal dust on the surface.

7. Vacuum drying: According to the product requirements, the qualified temperature, pressure and time of the drying box are selected to improve the electrical performance of the film capacitor products. It is required to ensure the accuracy of the parameters set by the machine.

8. Empowerment: Depending on the characteristics of the thin film capacitor product, choose a suitable incremental voltage to improve the electrical performance of the thin film capacitor product. Requires accurate voltage setting.

9. Welding: Weld the pins to the core. It is required that the wire diameter and length are correct, the position is moderate, the welding current is correct, the metal film cannot be ironed, the welding point is smooth, there are no burrs, and no virtual welding.

10. Plug-in: Insert the core into the plastic shell. The core is required to be in the middle of the shell and fixed

11. Encapsulation: Encapsulating the potting material in a plastic shell. It is required to mix the potting material correctly and stir well. There should be no resin at the lead-out end and the shell surface, no bubbles on the fat surface. The size is accurate.

12. Printing: Print relevant information on the surface of the material. It is required that the film capacitor's identification is correct, the silk screen is clear, centered, and it is not easy to fall off.

13. Shipment inspection: performance random inspection (capacity, loss, withstand voltage, insulation resistance) The appearance of the plastic shell should be smooth, without scratches, burrs, resin and other bad phenomena. The marking is clear and correct, the ink is even, no disconnection, incompleteness and other bad phenomena, the position is centered, no obvious offset, the silk screen is not easy to fall off, and the size of the film capacitor is attached to the inspection document requirements.

If you have technical questions, please contact us, we will try our best to solve it for you.