What are the differences between FPC and rigid PCBs?

What are the differences between FPC and rigid PCBs?

FPC (Flexible Printed Circuit) and rigid PCB (Rigid Printed Circuit Board) are two common circuit board types. They have the following differences:
**Material and Structure**: Material: The dielectric layers in FPCs are typically homologous sheets of flexible polyimide material. While in rigid PCBs, the dielectric layers are usually the composite of epoxy and glass fiber woven cloth.

FPC uses a flexible substrate, such as polyimide or polyester film, which is bendable and flexible; while rigid PCB uses a rigid substrate, usually glass fiber reinforced epoxy resin substrate.

**Application scenarios**: FPC is suitable for applications that require bending, folding, or working in dynamic environments, such as mobile devices, smart wearable devices, etc.; rigid PCB is more suitable for fixedly installed electronic equipment, such as computer hosts, Home appliances, etc.

**Wiring capability**: Due to the flexibility of FPC, it can achieve more complex wiring designs and is suitable for high-density, high-interconnection circuits; the wiring of rigid PCB is limited by the hardness of the substrate and is relatively simple.

**Prices**: Generally speaking, the manufacturing cost of FPC is higher because of its higher material and manufacturing process requirements; the cost of rigid PCB is relatively lower. FPCs are more expensive than rigid PCBs. But FPCs have plenty of benefits to improve the cost performance, like space-saving, weight-reducing, and high reliability, etc.

**Reliability**: FPC may face higher reliability challenges during repeated bending and dynamic use, such as the plug and unplug life of connectors; rigid PCBs are generally more reliable in static environments.

**Solder mask**: A rigid PCB has a solder mask on both sides with the SMT pads or PTH holes exposed for assembling components. FPCs usually use a thin polyimide material as a cover coat that can be drilled or laser-cut to access the components.

**Heat dissipation performance**: Rigid PCB usually has better heat dissipation performance because it can conduct heat through the substrate; FPC’s heat dissipation ability is relatively weak.

The choice between using an FPC or a rigid PCB depends on factors such as specific application needs, design requirements, and cost considerations. In some cases, both FPC and rigid PCB may be used to meet the circuit needs of different parts.