Terms related to FPC flexible circuit board

FPC is mainly used in many products such as mobile phones, laptops, PDAs, digital cameras, LCMS, etc. here are some common terms of FPC.
1. Access hole (through hole, bottom hole)
It often refers to the coverlay (through hole to be punched out first) on the surface of the flexible board, which is used to fit on the circuit surface of the flexible board as the anti welding film. However, the hole ring hole wall or square welding pad required for welding must be deliberately exposed to facilitate the welding of parts. The so-called “access hole” originally means that the surface layer has a through hole, so that the outside world can “approach” the plate solder joint under the surface protective layer. Some multilayer boards also have such exposed holes.
2. Acrylic acrylic
It is commonly known as polyacrylic acid resin. Most flexible boards use its film as the next film.
3. Adhesive adhesive or adhesive
A substance, such as resin or coating, that enables two interfaces to complete bonding.
4. Anchorage spurs claw
On the middle plate or single panel, in order to make the hole ring welding pad have stronger adhesion on the plate surface, several fingers can be attached to the excess space outside the hole ring to make the hole ring more consolidated, so as to reduce the possibility of floating from the plate surface.
5. Bendability
As one of the characteristics of dynamic flex board, for example, the quality of the flexible board connected to the print heads of computer disk drives shall reach the “bending test” of one billion times.
6. Bonding layer bonding layer
It usually refers to the adhesive layer between the copper sheet and the polyimide (PI) substrate of the film layer of multilayer board, or TAB tape, or the plate of flexible board.
7. Coverlay / cover coat
For the outer circuit of the flexible board, the green paint used for the hard board is not easy to be used for anti welding, because it may fall off during bending. It is necessary to use a soft “acrylic” layer laminated on the board surface, which can not only be used as anti welding film, but also protect the outer circuit, and enhance the resistance and durability of the soft board. This special “outer film” is specially called surface protective layer or protective layer.
8. Dynamic flex (FPC) flexible board
It refers to the flexible circuit board that needs to be used for continuous movement, such as the flexible board in the read-write head of disk drive. In addition, there is a “static FPC”, which refers to the flexible board that no longer acts after it is properly assembled.
9. Film adhesive
It refers to the dry laminated bonding layer, which can include the film of reinforcing fiber cloth, or the thin layer of adhesive material without reinforcing material, such as the bonding layer of FPC.
10. Flexible printed circuit, FPC flexible board
It is a special circuit board, which can change the shape of three-dimensional space during downstream assembly. Its substrate is flexible polyimide (PI) or polyester (PE). Like the hard board, the soft board can make plated through holes or surface adhesive pads for through hole insertion or surface adhesive installation. The board surface can also be attached with a soft cover layer for protection and anti welding purposes, or printed with a soft anti welding green paint.
11. Flexure failure
The material (plate) is broken or damaged due to repeated bending and bending, which is called flexible failure.
12. Kapton polyamide soft material
This is the trade name of DuPont’s products. It is a kind of “polyimide” sheet insulating soft material. After pasting calendered copper foil or electroplated copper foil, it can be made into the base material of flexible plate (FPC).
13. Membrane switch
With transparent Mylar film as the carrier, silver paste (silver paste or silver paste) is printed on thick film circuit by screen printing method, and then combined with hollowed gasket and protruding panel or PCB to become a “touch” switch or keyboard. This small “key” device is commonly used in hand-held calculators, electronic dictionaries, and remote controls of some household appliances. It is called “membrane switch”.
14. Polyester films
Referred to as PET sheet, the common product of DuPont is Mylar films, which is a material with good electrical resistance. In the circuit board industry, the transparent protective layer on the imaging dry film surface and the solder proof coverlay on the FPC surface are PET films, and they can also be used as the substrate of silver paste printed film circuit. In other industries, they can also be used as the insulating layer of cables, transformers, coils or tubular storage of multiple ICs.
15. Polyimide (PI) polyamide
It is an excellent resin polymerized by bismaleimide and aromaticdiamine. It is known as kerimid 601, a powdery resin product launched by French “Rhone Poulenc” company. DuPont made it into a sheet called Kapton. This pi plate has excellent heat resistance and electrical resistance. It is not only an important raw material for FPC and tab, but also an important plate for military hard board and supercomputer motherboard. The mainland translation of this material is “polyamide”.
16. Reel to reel interlocking operation
Some electronic parts and components can be produced by the retraction and retraction process of reel (disc), such as tab, lead frame of IC, some flexible boards (FPC), etc. the convenience of retraction and retraction of reel can be used to complete their online automatic operation, so as to save the time and labor cost of single piece operation.