Features
A common design guideline for a rigid flex PCB is the four layer process. A pliable polyimide, or plastic, core is surrounded by copper foil for conduction of signals on either side. Sandwiched above and beneath this construct are two layers of FR-4 laminate, or the typical, green, PCB-weaved baseboard.

Considerations
Because of the intricacies of the design, production and fabrication of rigid flex costs five to seven times more than a standard PCB. But, depending on the application, this may be the only PCB that will work, especially if it is for a small electronic device necessitating a thin board.

Identification
A rigid flex PCB varies from its stiff PCB predecessor. Rigid flex uses stiff and flexible materials to create the circuitry needed for a product. Multiple PCBs connected with cabling which used to be the normal design are now constructed into one three-dimensional PCB body.