If you simply use "flexible board + circuit board + connector" to compare "flexible and rigid board", its biggest disadvantage is that the price of "flexible and rigid board" is relatively expensive, and there may be more than the original simple "flexible board + The price of "hard board" is nearly double; but if the price of the connector or the cost of the HotBar is deducted, the price may tend to be the same. The detailed cost may have to be actuarial to have a clearer outline. Another disadvantage is that it may be necessary to use a carrier to support the part of the soft board during part-making and furnace passing, which virtually increases the assembly cost of SMT.
Advantages of rigid-flex board
In addition to the price, there are many advantages of using rigid-flex boards as follows:
1. It can effectively save the space on the circuit board and save the process of using connectors or HotBarBecause the FPCB soft and hard combination board has been combined, the space that originally needs to use the connector or the HotBar process can be saved. For some circuit boards with high density requirements, one less connector is needed. Space is like picking up a treasure.
This also saves the cost of parts using the connector or the cost of the HotBar process. In addition, the space between the two boards will become tighter due to the omission of connectors
2. The distance of signal transmission is shortened and the speed is increased, which can effectively improve the reliability
The traditional signal transmission through the connector is "circuit board → connector → flexible board → connector → circuit board", while the signal transmission of the soft and hard composite board is reduced to "circuit board → flexible board → circuit board". The distance is shortened, and the problem of signal transmission attenuation between different media is also reduced. Generally, the lines on the circuit board are made of copper, while the contact terminals of the connector are gold-plated. The solder pins are plated with full tin, and It is necessary to use solder paste to solder on the circuit board, and the signal transmission between different media will inevitably be attenuated. If you switch to a rigid-flex board, these media will become less, and the ability of signal transmission can also be relatively improved. Some products that require high signal accuracy can help improve their reliability.
3. Simplify product assembly and save assembly man-hours
The use of soft and hard boards can reduce the man-hours of SMT packaging, because the number of connectors is reduced. It also reduces the man-hours for the assembly of the whole machine, because the assembly action of inserting the soft board into the connector is omitted, or the process of HotBar is omitted. It also reduces the cost of parts management and inventory, because the BOM table is reduced, so the management becomes less.
