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What are PCB board materials?

With the continuous expansion of PCB market capacity, the demand of PCB board is also increasing. How to select the most suitable plate for proofing has become a problem considered by many engineers.

1、 Concept

PCB board is the basic material of PCB, often called substrate. Copper clad laminate (full name of copper clad laminate) is a product made of wood pulp paper or glass fiber cloth as reinforcement material, impregnated with resin, covered with copper foil on one or both sides, and hot pressed. Copper clad laminate is the basic material of electronic industry. It is mainly used to manufacture printed circuit board (PCB). It is widely used in television, radio, computer, computer, mobile, communication and other electronic products.

2、 Classification

According to different classification standards, the classification is as follows:

Engineers often pay much attention to a Tg value when selecting plates. In particular, what is TG and the classification of CCL according to TG should be introduced.

Glass transition temperature Tg (glass transition temperature): the temperature at which a polymer changes from a glass state to a high elastic state. Glass transition temperature is an important parameter for the physical changes of polymers, which is mainly related to the structure, aggregation state and crosslinking density of polymers. For designers, TG is an important item to measure and characterize the heat resistance of some glass fiber cloth based copper clad laminates (such as FR-4). For example: tg140 ℃, tg160 ℃, tg180 ℃, etc. Therefore, for high reliability design, designers tend to choose high Tg plate. As a symbol of heat resistance of plate in lead welding, TG is representative indeed.

3、 Classification

According to the grade level, it is divided from bottom to top as follows:

Fr-4a1: this level is mainly used in military, communications, computers, digital circuits, industrial instruments, automotive circuits and other electronic products.

Fr-4a2: this level is mainly used for ordinary computers, instruments, advanced household appliances and general electronic products. This series of copper clad laminates are widely used, and each performance index can meet the needs of general industrial electronic products.

Fr-4a3: This grade of copper clad laminate is a FR-4 product specially developed and produced for home appliance industry, computer peripheral products and ordinary electronic products (such as toys, calculators, game machines, etc.). Its characteristic is that the price is very competitive on the premise that the performance meets the requirements.

Fr-4ab grade: This grade plate is a unique low-grade product. However, the performance indicators can still meet the needs of ordinary household appliances, computers and general electronic products. Its price is the most competitive, and the performance price ratio is also quite excellent.

Fr-4b grade: the board of this grade belongs to the inferior product board, the quality stability is poor, it is not suitable for the circuit board products with large area, generally applicable to the products with size of 100mmx200mm. Its price is the lowest, but customers should pay attention to the choice of use.

CEM-3 series: this kind of product has three kinds of substrate color, namely white, black and natural color. It is mainly used in computer, LED industry, clocks, general household appliances and ordinary electronic products (such as VCD, DVD, toys, game machines, etc.). Its main feature is good punching performance, suitable for large quantities of PCB products which need stamping process forming. This series of products have A1, A2, A3 three quality levels of products, a variety of different requirements of customers, can choose to use.

According to the PCB board reinforcement materials are generally divided into the following:

1. Phenolic PCB paper substrate

Because this kind of PCB is composed of pulp, wood pulp, etc., it sometimes becomes paperboard, V0 board, flame retardant board and 94hb, etc. its main material is wood pulp fiber paper, which is pressed and synthesized by phenolic resin.

This paper substrate is not fireproof, can be punched, low cost, low price, low relative density. Phenolic paper substrate we often see XPC, FR-1, FR-2, Fe-3 and so on. And 94v0 belongs to flame retardant paperboard, which is fireproof.

2. Composite PCB substrate

This kind of powder board is also made of wood pulp fiber paper or cotton pulp fiber paper as reinforcement material and glass fiber cloth as surface reinforcement material. The two materials are made of flame retardant epoxy resin. There are single-sided semi glass fiber 22F, CEM-1 and double-sided semi glass fiber board CEM-3, among which CEM-1 and CEM-3 are the most common composite matrix copper clad laminates.

3. Fiberglass PCB substrate

Sometimes it is also called epoxy board, glass fiber board, FR4, fiberboard, etc. it uses epoxy resin as adhesive and glass fiber cloth as reinforcement material. This kind of circuit board has high working temperature and little environmental impact. It is often used in double-sided PCB, but its price is higher than that of composite PCB substrate. The common thickness is 1.6mm. This kind of substrate is suitable for all kinds of power supply boards and high-rise circuit boards, and is widely used in computers, peripherals and communication equipment.

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