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PCB board different material difference

  • PCB
  • PCB board quality
2024-09-20

   The flammability of the material, also known as flame retardant, self-extinguishing fire resistance, flame resistance, fire resistance, flammability and other combustibility is to assess the ability of the material to resist combustion.

   The combustible material samples are ignited with a flame that meets the requirements, the flame is removed at a specified time, and the combustibility grade is assessed according to the degree of sample combustion. It is divided into three levels. The horizontal test method for the sample is divided into FH1,FH2 and FH3 levels; the vertical test method for the sample is divided into FV0,FV1 and VF2 levels.

Solid PCB plate has HB plate and V0 plate.


HB plate has low flame retardant and is mostly used for single panel.

VO plate has high flame retardancy and is mostly used for double panel and multi-layer board

This type of PCB board that meets the requirements of V-1 fire rating becomes FR-4 board.

V-0,V-1,V-2 are fire ratings.


   The circuit board must be flame resistant, can not burn at a certain temperature, can only be softened. At this time, the temperature point is called the glass transition temperature (Tg point), and this value is related to the size stability of the PCB board.


What are high Tg PCB boards and the advantages of using high Tg PCB?

   When the temperature of high Tg printed board rises to a certain area, the substrate will change from a "glass state" to a "rubber state", and the temperature at this time is called the glass transition temperature (Tg) of the board. In other words, Tg is the highest temperature at which the substrate remains rigid.


What are the specific types of PCB boards?

According to the grade level from bottom to high divided as follows:

94HB-94VO-22F-CIM-1-CIM-3-FR-4

The details are as follows:

94HB: ordinary cardboard, not fireproof (lowest grade material, die punching, can not be used as a power board)

94V0: Flame retardant board (die punching)

22F: Single side half glass fiber board (die punching)

Cim-1: Single glass fiber board (must be computer drilling, can not die punching)

Cim-3: double-sided half-glass fiber board (except double-sided cardboard is the lowest end of the double-panel material, simple

Double panel can use this material, than FR-4 will be cheaper 5~10 yuan/square meter)

FR-4: double-sided fiberglass board


   The circuit board must be flame resistant, can not burn at a certain temperature, can only be softened. At this time, the temperature point is called the glass transition temperature (Tg point), and this value is related to the size stability of the PCB board.

   What is a high Tg PCB board and the advantages of using a high Tg PCB High Tg printed board When the temperature rises to a certain area, the substrate will change from a "glass state" to a "rubber state", and the temperature at this time is called the glass transition temperature (Tg) of the board. In other words, Tg is the highest temperature (° C) at which the substrate remains rigid. That is to say, ordinary PCB substrate materials at high temperatures, not only produce softening, deformation, melting and other phenomena, but also show a sharp decline in mechanical and electrical characteristics (I think you do not want to see the classification of pcb board to see their own products appear in this situation).


The plate of general Tg is more than 130 degrees, the high Tg is generally greater than 170 degrees, and the medium Tg is about more than 150 degrees.

Usually Tg≥170℃ PCB printed board, called high Tg printed board.

   The Tg of the substrate is increased, and the heat resistance, moisture resistance, chemical resistance, and stability of the printed board will be improved and improved. The higher the TG value, the better the temperature resistance of the plate, especially in the lead-free process, high Tg is more applied.

   High Tg means high heat resistance. With the rapid development of the electronics industry, especially the electronic products represented by computers, towards the development of high function and high multilayer, the higher heat resistance of PCB substrate materials is required as an important guarantee. The emergence and development of high-density installation technology represented by SMT and CMT has made PCB more and more inseparable from the support of high heat resistance of the substrate in terms of small aperture, fine wiring and thin shape.

   Therefore, the difference between the general FR-4 and the high Tg FR-4 is that in the hot state, especially under heat after hygroscopic, the mechanical strength, dimensional stability, adhesion, water absorption, thermal decomposition, thermal expansion and other conditions of the material are different, and high Tg products are obviously better than ordinary PCB substrate materials.

   In recent years, the number of customers requiring the production of high Tg printed boards has increased year by year.


   With the development and continuous progress of electronic technology, new requirements are constantly put forward for printed board substrate materials, thus promoting the continuous development of copper clad foil board standards. At present, the main standards for substrate materials are as follows.

① National standards At present, China's national standards for the classification of pcb boards as substrate materials include GB/T4721-47221992 and GB4723-4725-1992. The standards for copper clad laminates in Taiwan, China, China, are CNS standards, which were formulated based on Japanese JIS standards and issued in 1983.

② Main standards of other national standards are: JIS standards in Japan, ASTM, NEMA, MIL, IPc, ANSI, UL standards in the United States, Bs standards in the United Kingdom, DIN, VDE standards in Germany, NFC and UTE standards in France, CSA standards in Canada, and AS standards in Australia. The FOCT standard of the former Soviet Union, the international IEC standard, etc.


   The suppliers of the original PCB design materials are common and commonly used: Shengyi \ Jiantao \ International and so on.

● Accepted documents: protel autocad powerpcb orcad gerber or solid board copy board, etc

● Plate type: CIM-1, CIM-3 FR4, high TG material;

● Maximum panel size: 600mm*700mm(24000mil*27500mil)

● Plate thickness: 0.4mm-4.0mm(15.75mil-157.5mil)

● Maximum number of processing layers: 16Layers

● Copper foil layer thickness: 0.5-4.0(oz)

● Finished plate thickness tolerance: +/-0.1mm(4mil)

● Dimensional tolerance: Computer milling: 0.15mm(6mil) Die punching: 0.10mm(4mil)

● Minimum line width/pitch: 0.1mm(4mil) Line width control: < + -20%

● Minimum borehole size: 0.25mm(10mil)

Minimum punch size: 0.9mm(35mil)

Finished aperture tolerance: PTH: +-0.075mm(3mil)

NPTH: +-0.05mm(2mil)

● Copper thickness of finished hole wall: 18-25um (0.71-0.99mil)

● Minimum SMT pitch: 0.15mm(6mil)

● Surface coating: chemical gold deposition, tin spray, whole plate nickel gold plating (water/soft gold), silk screen blue glue, etc

● Solder resistance film thickness: 10-30μm(0.4-1.2mil)

● Peeling strength: 1.5N/mm (59N/mil)

● Welding resistance film hardness: > 5H

● Solder resistance plug capacity: 0.3-0.8mm(12mil-30mil)

● Dielectric constant: ε= 2.1-10.0

● Insulation resistance: 10KΩ-20MΩ

● Characteristic impedance: 60 ohm± 10%

● Thermal shock: 288℃, 10 sec

● Finished plate warpage: < 0.7%

● Product application: communication equipment, automotive electronics, instrumentation, global positioning system, computer, MP4, power supply, home appliances, etc


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

1.phenolic PCB paper substrate

   Because this PCB board is composed of pulp wood pulp, etc., it is sometimes also become cardboard, V0 board, flame retardant board and 94HB, etc. Its main material is wood pulp fiber paper, pressurized by phenolic resin and synthesized a PCB board.

This paper substrate is characterized by no fire, can be punched processing, low cost, cheap price, relatively small density. Phenolic paper substrate we often see XPC, FR-1, FR-2, FE-3 and so on. And 94V0 belongs to flame retardant cardboard, is fireproof.


2.composite PCB substrate

   This also becomes a powder board, with wood pulp fiber paper or cotton pulp fiber paper as the reinforcement material, while supplemented by glass fiber cloth as the surface reinforcement material, both materials are made of flame retardant epoxy resin. There are single-side semi-glass fiber 22F, CIM-1 and double-side semi-glass fiber plate CIM-3, among which CIM-1 and CIM-3 are the most common composite base copper clad plates at present.


3. glass fiber PCB substrate

   Sometimes it is also known as epoxy board, glass fiber board, FR4, fiberboard, etc., which uses epoxy resin as a binder and glass fiber cloth as a reinforcing material. This circuit board has a high operating temperature, is little affected by the environment, and is often used in double-sided PCB, but the price is more expensive than the composite PCB substrate, and the common thickness is 1.6MM. The substrate is suitable for various power supply boards, high-rise circuit boards, and is widely used in computers and peripheral equipment, communication equipment and so on.


FR-4


4.Other substrates

In addition to the three commonly seen above, there are also metal substrates and laminated multilayer boards (BUM).




*Disclaimer: This article is from the Internet, if there is any dispute, pleasecontact customer service.

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