The product characteristics of the soft FPCB board, in addition to the soft material, there are light texture, thin or light configuration structure, materials can be repeated bending without insulation material fracture condition of rigid PCB, soft board soft plastic substrate and wire layout, let the soft board to meet the high conduction current, voltage, so the application of high power electronic circuits can hardly see the soft board design, but in the small current and low power consumption of electronic products, the use of the soft board is quite large.
Because the cost of soft board still the key materials of PI, higher unit costs, so in the process of product design, is not in the soft board as the main board, the key design but localized application of "soft" characteristics of the.
PI is also called "PI" in polyimide, from its heat resistance, the molecular structure is different, can be divided into aromatic PI, semi aromatic PI different structure, aromatic PI belongs to straight chain type, material does not melt and immiscible thermoplastic material, melting characteristics of materials in production when the method of injection molding, but the material can be compressed, sintering, and the other one can adopt injection molding production.
In addition to the main material characteristics, the structure of the FPCB substrate is also a key, FPCB as the cover film as insulation and protection materials, with the insulation substrate, rolled copper foil, followed by the composition of the overall FPCB. The substrate material FPCB with insulating properties, commonly used polyester (PET), polyimide (PI) or PI PET two materials, each has its advantages and disadvantages.
FPCB is used in a wide range of products, but basically no more than leads, printed circuits, connectors, and multi-functional integration systems. If the function is divided into space design, can change its shape, folding, bending design mining group, while the FPCB design can be used to prevent electrostatic interference of electronic equipment. The use of flexible circuit board, regardless of the cost, so that the quality of production directly on the soft board structure, not only the design volume is relatively narrow, the overall product volume can also be greatly reduced due to the characteristics of the plate.
The substrate structure of FPCB is quite simple, mainly from the top protection layer and the middle conductor layer. When the mass production is carried out, the soft particle board can be matched with the positioning hole for the production program alignment and post-processing. As for the use of FPCB, according to the space needed to change the plate shape, or folded form, but as long as the multilayer structure in the outer mining anti EMI, form static barrier design, flexible circuit board can do to improve the design of efficient EMI problem.
In the process of FPCB, will be the first copper foil and the substrate, truncation processing take perforation, electroplating operations, generally in the FPCB hole in advance is completed, begin photoresist coating, exposure and development program that FPCB coating finish, pre etched lines will be ready for processing, complete exposure and development after treatment by solvent etching operation, then etched to a certain extent that the conduction line is forming, surface cleaning to remove the solvent, then the adhesive evenly coated copper foil in FPCB base and the etching surface, and then attached processing layer.
The completion of the operation, FPCB is already completed 80% degrees, then we need to connect the FPCB for processing, such as increasing the welding processing guide hole, then another shape processing of FPCB, such as the use of laser cutting special appearance, if FPCB is the soft and hard composite plates, or for welding processing and function module at this time, then two times the processing, or collocation reinforcement plate processing design.
FPCB uses quite diverse, but the manufacturing difficulty is not high, but FPCB itself can not make too complicated, tight line, because the circuit is too thin because of copper foil cross-sectional area is too small, if the deflection of FPCB, it is easy to make the interior of the line is broken, the demand of HDI high density multilayer board processing circuit so Yu Fanfu is likely to use the core, only a large number of data transmission or data transmission I/O interface, different function board connection, will use FPCB to carry out the plate connection.