When to Use Rigid PCB and When to Use Flex PCB

Some manufacturers use hybrid rigid flexible printed circuit boards, which are connected to each other through ribbon flexible circuits for product manufacturers. By focusing on the advantages of each circuit board basic technology, the rigid flexible board can be compounded and designed to meet various engineering requirements. These boards are commonly used in the manufacture of medical devices and other high reliability products.

It is strongly recommended that you consult your PCB and PCBA service providers before you start a project to ensure that you make effective use of the provider’s capabilities.

The cost of rigid pcb is usually less than that of flexible circuit. I say “usually” because some applications are cheaper to use flexible PCB than rigid pcb when considering total cost of ownership. to really and accurately understand the entire cost of ownership, you initially got to understand the very fact that flexible circuits can eliminate the necessity for components like connectors, wiring harness, and other circuit boards. By removing these components from the planning , you’ll reduce material costs, labor and assembly costs, and scrap costs.

Many electronic devices (portable and desktop computers, audio keyboards, solid-state drives (SSD), flat-panel TVs and displays, children’s toys, and various electronic products) use rigid PCBs rather than flexible PCBs. However, flexible circuits may appear in ultra compact and / or high-performance devices, including GPS devices, tablets, smart phones, cameras and wearable devices.

Complexity isn’t the sole reason to use flexible circuits; in some cases, low technology applications, like LED lights under the counter, may use flex circuit technology because it makes installation easier.

Finally, if necessary, flexible circuits and rigid circuits are often used together (as a unified PCB). Perhaps this approach offers two advantages.

Some Similarities and Differences between Rigid PCB and Flex PCB

When designing rigid pcb, some design rules must be followed, including minimum hole size, minimum space and wire width, minimum distance to board edge, and copper and overall design thickness. additionally , rigid and flex PCBs share many manufacturing process steps. These processing steps include drilling and plating holes and vias, photographic imaging and development, etching of copper traces, pads, profiles and planes, and heating (baking) of circuit boards to get rid of moisture from PCB. At now within the manufacturing process, the rigid computer circuit board results in the solder mask station, while the flexible circuit enters the cladding station.

IPC Standard for Rigid and Flex PCB

The following list of IPC standards is applicable to rigid pcb and flex pcb. Please note that this list isn’t exhaustive and other IPC standards may have to be considered. you ought to visit ipc.org Website for an entire list of obtainable IPC standards.

• Ipc-2221a, general standard for PCB design
• Ipc-2223, a part of the planning standard for flexible printed boards
• Ipc-4101, specification for basic materials for rigid and multilayer printed boards
• Ipc-4202, flexible base dielectric for flexible printed circuits
• Ipc-4203, an adhesive coated dielectric film used as a covering layer for flexible computer circuit boards and flex adhesive bonding films
• Ipc-4204, flexible metal coated dielectric for flexible computer circuit boards
• Ipc-6013, qualification and Performance Specification for flexible printed circuits

Will flexible circuits replace rigid boards in all applications?

No, although flexible boards are useful and can be used in a wide range of applications, they do not replace rigid boards.

For manufacturers, the costs associated with the efficiency of implementing proprietary FPC designs in consumer products can be high, which directly affects consumers. The manufacturing and installation costs of rigid circuit boards are low (when using standard automated mass manufacturing equipment).

Most innovative products include flexible circuits when necessary, and where possible use robust and reliable rigid circuit boards to reduce manufacturing and assembly costs.

Conclusion

Although rigid and flex computer circuit boards fundamentally achieve an equivalent purpose (connecting various electrical and mechanical components), both technologies have their place in life. Both rigid and flex PCBs use many of an equivalent design rules, while flexible PCBs require additional manufacturing process steps and thus require another rules. Moreover, while rigid PCBs seem to scale back costs a minimum of initially, consider the entire cost of ownership of the planning before declaring flexible circuits too expensive.

Finally, it should be noted that not all PCB manufacturers can manufacture flexible PCB. Before you begin designing flexible circuits, you ought to interview multiple board manufacturers and discuss flexible PCB construction options and related costs.