From the analysis of the basic structure of the flexible printed circuit board, the materials that constitute the flexible printed circuit board include insulating substrates, adhesives, metal conductor layers (copper foil) and cover layers.

1.1 Copper foil substrate

Copper foil: basically divided into two types: electrolytic copper and rolled copper. Common thicknesses are 1oz 1/2oz and 1/3oz

Substrate film: Common thicknesses are 1mil and 1/2mil.

Glue (adhesive): The thickness is determined according to customer requirements.

1.2 Overlay Protective Film

Cover film protective film: for surface insulation. Common thicknesses are 1mil and 1/2mil.

Glue (adhesive): The thickness is determined according to customer requirements.

Release paper: avoid the adhesive from adhering to foreign matter before pressing; easy to operate.

1.3 Reinforcing plate

Reinforcing plate: Reinforcing the mechanical strength of FPC, facilitating surface mounting operations. Common thicknesses are 3mil to 9mil.

Glue (adhesive): The thickness is determined according to customer requirements.

Release paper: Avoid the adhesive from sticking to foreign matter before pressing.

EMI: Electromagnetic shielding film, which protects the circuit in the circuit board from interference from the outside world (strong electromagnetic area or susceptible area).