What is the manufacturing process flow of FPC flexible boards for unmanned aerial vehicles

The manufacturing process of FPC (Flexible Printed Circuit Board) flexible boards for unmanned aerial vehicles is a complex and delicate process, involving multiple key steps. The following is a typical overview of the manufacturing process flow of FPC flexible boards for unmanned aerial vehicles:

I. Material Preparation

Base material selection: The main base material of the FPC flexible board for unmanned aerial vehicles is usually polyimide (PI) or polyester (PET) film. These materials have good flexibility, heat resistance and chemical resistance.

Copper foil adhesion: A layer of copper foil is covered on the surface of the substrate. The thickness of the copper foil is usually between 12μm and 35μm, and the specific choice depends on the current demand and design requirements. Rolled copper foil has good flexibility and is suitable for high-frequency electronic products, while electrolytic copper foil has better electrical conductivity and is suitable for high-current circuits.

Cleaning treatment: Clean the base material and copper foil to ensure that the surface is free of dust and dirt, which is conducive to the bonding effect of subsequent processes.

Ii. Circuit Production

Dry film photolithography: A layer of dry film photoresist is coated on copper foil, and then the circuit pattern is revealed through exposure and development, while the conductive path is retained.

Etching: Use an etching agent to remove the unwanted copper, leaving only the designed part of the circuit. The etched circuits are cleaned and dried to form the basic conductive patterns.

Surface treatment: To enhance welding performance and prevent oxidation, the surface of FPC usually needs to be treated. Common surface treatment processes include electroless gold plating, silver plating or organic solder mask (OSP) treatment.

Iii. Lamination and Covering Film

Covering film: A protective film is applied to the conductive pattern to prevent oxidation or damage to the circuit. The covering film needs to be pressed under high temperature and high pressure to ensure its good adhesion to the circuit.

Lamination: For multi-layer FPC flexible boards, it is necessary to combine each layer together through lamination processes to ensure the stability of electrical connections between layers and the overall structure.

Iv. Forming and Cutting

Drilling: Drill out holes, through holes or installation holes according to the design drawings. These holes are used for electrical connections between multiple layers of FPCS or for the fixation of components. Drilling methods include laser drilling and mechanical drilling. Laser drilling, due to its high precision and small hole diameter, is suitable for miniaturized design.

Hole metallization: Electroplating is carried out in the through-hole to form a metal channel, ensuring the conduction between the upper and lower layers of circuits.

Cutting and forming: According to the designed shape, the FPC is punched or laser-cut to the specified size to form the final plate shape. This process requires precision to ensure that the dimensions of the finished product meet the design requirements

V. Testing and Packaging

Test: Conduct electrical performance tests on the finished products to ensure that the circuits are well connected, the insulation meets the standards, and there are no short circuits or open circuits. In addition, bending tests, tensile strength tests, etc. may also be conducted to verify the reliability of FPC flexible boards.

Packaging: Package the FPC flexible boards that have passed the test to prevent damage during transportation and storage.