Flex
PCB board are mainly used in many products such as mobile phones, notebook computers, PDAs, digital cameras, LCMs, etc. The following is an introduction to the commonly used terms related to FPC.
1. Access Hole (through hole, bottom hole)
Often refers to the protective layer Coverlay on the surface of the flexible board (the perforation hole that must be punched out first), which is used to fit on the surface of the flexible board circuit as a solder mask. However, it is necessary to deliberately expose the hole ring hole wall or square solder pad required for welding to facilitate the welding of parts. The so-called "Access Hole" in the original text means that the surface has a perforation hole, which enables the outside world to "close" to the solder joints on the board under the surface sheath. Some multilayer boards also have such exposed holes.
2. Acrylic
It is a common name for polyacrylic resin, and most of the soft boards use its film as a subsequent film.
3. Adhesive glue or adhesive
Substances, such as resin or paint, that can make the two interfaces complete the bonding.
4. Anchoring Spurs
On the middle board or single board, in order to make the hole ring pads have stronger adhesion properties on the board surface, a few fingers can be added to the extra space outside the hole ring to make the hole ring more powerful. Consolidate to reduce the chance of floating off the board.
5. Bandability Bendability, bending ability
As a characteristic of Dynamic Flex Board, such as the flex board connected to the print head of a computer disk drive, its quality should reach one billion "bend tests".
6. Bonding Layer
Often refers to the film layer of the multi-layer board, or the TAB tape, or the sheet of the flexible board, the adhesive layer between the copper skin and the polyimide (PI) substrate.
7. Coverlay/Cover Coat surface protection layer, protective layer
For the outer layer of the soft board, the solder mask is not easy to use the green paint used for the hard board, because it may fall off when it is bent. It is necessary to use a soft "acrylic" layer to laminate the board surface, which can be used as a solder mask and protect the outer circuit, and enhance the resistance and durability of the soft board. "Outer membrane" is specifically referred to as the outer covering or protective layer.
8. Dynamic Flex (FPC) dynamic soft board
Refers to the flexible circuit board that needs to be used for continuous motion, such as the flexible circuit board in the read-write head of a disk drive. In addition, there is another "Static FPC" (Static FPC), which refers to the type of FPC that no longer moves after it is properly assembled.
9. Film Adhesive then film, adhesive film
It refers to the adhesive layer of dry lamination, which can be a film containing reinforcing fiber cloth, or a thin layer without reinforcing material and only adhesive material, such as the adhesive layer of FPC.
10. Flexible Printed Circuit, FPC soft board
It is a special circuit board that can be changed in three-dimensional space during downstream assembly, and its substrate is flexible polyimide (PI) or polyester (PE). This flex board, like a rigid board, can be made with plated through holes or surface mount pads for through-hole or surface mount. The surface of the board can also be attached with a soft cover layer for protection and solder mask, or printed with a soft solder mask green paint.
11. Flexural Failure flexural damage
The material (plate) is broken or damaged due to repeated bending and flexing actions, which is called Flexural Failure.
12. Kapton polyimide soft material
This is the trade name of DuPont's products. It is a kind of "polyimide" sheet-like insulating soft material. After pasting with rolled copper foil or electroplated copper foil, it can be made into the base material of flexible board (FPC). .
13. Membrane Switch membrane switch
Using the transparent polyester (Mylar) film as the carrier, the silver paste (SilverPastes or silver paste) is printed on the thick film circuit by the screen printing method, and then the hollow spacer is matched with the protruding panel or PCB board. Combined, it becomes a "tactile" switch or keyboard. Such small "key" devices are commonly used in handheld calculators, electronic dictionaries, and remote controls for some home appliances, etc., and are called "membrane switches".
14. Polyester Films polyester sheet
PET flakes for short, commonly known as MylarFilms, a product of DuPont, is a material with good electrical resistance. In the circuit board industry, the transparent protective layer on the surface of the imaging dry film and the coverlay on the surface of the flexible board (FPC) are all PET films, and they can also be used as the substrate for silver paste printed film circuits (MembraneCircuit). In the electronics industry, it can also be used as an insulating layer for cables, transformers, coils, or as a tubular storage device for multiple ICs.
15. Polyimide (PI) Polyimide
It is an excellent resin that is co-polymerized by Bismaleimide and Aromaticdiamine. It is known as Kerimid 601, a powdery resin product launched by the French "Rhone-Poulenc" company. DuPont made it into a sheet called Kapton. This kind of PI sheet has excellent heat resistance and electrical resistance. It is an important raw material for flexible board (FPC) and tape automatic bonding (TAB), as well as an important board for military hard boards and supercomputer motherboards. Its translation name is "polyacryloamide".
16. Reel to Reel reel (disk) linked operation
Some electronic parts and components can be produced by the reel (reel) retractable process, such as TAB, IC lead frame, some flexible boards (FPC), etc., which can be retracted and reeled using tape It is convenient to complete its online automatic operation to save the time and labor cost of single-piece operation on PCB board.
