Film capacitor manufacturing process and requirements

We all know that film capacitors are made of metal foil as an electrode, and it is a capacitor made of polyethylene, polypropylene, polystyrene, or polycarbonate, which is overlapped from both ends and wound into a cylindrical shape. But do you know how it works? And what are the requirements when making?

1. Film cutting: Cut the metal foil into the required design width with the film cutting machine according to the product design capacity. 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 both 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 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 drying box should choose the qualified temperature, pressure, and time 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. Enabling: 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. Insert: Insert the core into the plastic case. The core is required to be in the middle of the shell and fixed

11. Encapsulation: Encapsulate 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 should be smooth, without scratches, burrs, resin, etc. The marking is clear and correct, the ink is even, there is no bad phenomenon such as disconnection, incompleteness, etc., the location is in the middle; the silk screen is not easy to fall off without obvious deviation, and the size of the film capacitor is attached to the inspection document requirements.

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