Flexible and Flex-Rigid 

Flexible and flex-rigid printed circuit boards, unlike rigid PCBs, can bend, twist and fold.

They are intended for dynamic applications, as an electro-mechanical connection element between electronic parts called upon to bend hundreds of thousands of times. They can also be used in static applications, where several rigid portions of a single flex-rigid PCB are connected together by flexible parts, to maximise the number of electronic components in restricted spaces.

It is difficult to solder components and achieve a large number of interconnections on simple flexible products. One solution is to use a stiffener. Part of the circuit becomes rigid, to facilitate additions and soldering on components while increasing the number of interconnections. However, a stiffener is not usually part of a printed circuit board. In flex-rigid PCBs, on the other hand, the rigid parts are also part of the circuit board.

In recent years the use of flexible and flex-rigid PCBs has grown exponentially because the benefits have been understood, including:

• the possibility of reducing the necessary space thanks to the 3D “architecture”
• avoiding the use of wiring and connection connectors between different PCBs
• and, therefore, being able to have a single printed circuit board to manage and test
• minimising the risk inherent to soldering 
• and reducing assembly costs.

Positive effects deriving from the use of flex-rigid PCBs also include:

• increased reliability and weight reduction
• increased signal integrity
• reduction in the loss of signal to the connectors

Moreover, flex-rigid printed circuit boards can also be made

• with mixed materials for RF applications and
• with HDI construction.