Flexure and reliability of 1 and FPC flexible PCB
At present, there are four kinds of flexible PCB: single side, double side, multi-layer, soft and hard combination.
1.single sided FPC is the lowest cost PCB with low electrical performance.
2. Double sided FPC has a layer of conductive pattern etched on both sides of the insulating basement membrane.
3. multilayer FPC is a single or double-sided flexible circuit of 3 or more layers, forming a metallized hole through drilling and electroplating and forming a conductive path between different layers. In this way, there is no need for a complex welding process.
4. The hard and soft joint board is composed of rigid and flexible substrate with selective formation pressure. The structure is compact, and the conductive connection is formed by metallized holes.

The economy of 2 and FPC flexible PCB
Flexible circuit is a better design option because of its complex circuit, processing many signals, or having special electrical or mechanical performance requirements. Flexible assembly is the most economical method when the size and performance of the application exceed the capability of rigid circuit. A 12mil pad with 5MIL through holes and a flexible circuit with 3mil lines and spacing can be made on a thin film.
High cost raw materials are the main reasons for the high price of flexible circuits. The price of raw materials varies greatly. The cost of the raw material used for the lowest cost polyester flexible circuit is 1.5 times that of the raw material used in the rigid circuit, and the high performance polyimide flexible circuit is up to 4 times or more.


The cost of 3 and FPC flexible PCB
In spite of the above cost factors, the price of flexible assembly is decreasing, which is similar to the traditional rigid circuit. The main reason is the introduction of updated materials, improved production processes and altered structures. The present structure makes the thermal stability of the product higher, and very few materials do not match. Some of the newer materials can make more precise lines because of the thinner copper layer, making the components lighter and more suitable for small space.