Types of PCB materials.

PCB materials are many, such as fiberglass, paper, metal, and plastic, and there are many, as well as high-frequency PTFE, etc.

PCB types

A. Divided by material

a. Organic materials

Phenolic resin, fiberglass/epoxy resin, Polyimide, BT/Epoxy, etc. are all included.

b. Inorganic materials

Aluminum, Copper-invar-copper, ceramic, etc. are all included. Mainly for its heat dissipation function

B. Divided by the hardness and softness of the finished product

a. Rigid PCB

b. Flexible PCB See Figure 1.3

c. Rigid-Flex PCB See Figure 1.4

C. Divided by structure

D. Divided by use: communication/consumable electronics/military/computer/semiconductor/electrical test board..., see Figure 1.8 BGA.

There is also a three-dimensional PCB made by injection molding, which is rarely used and will not be introduced here.

What are the types of PCB materials?

94V-0 and 94V-2 belong to a class of flame retardant materials, and 94V-0 is the highest flame retardant material among these two.

PCB boards are generally divided into several colors, what are the functional differences?

Green is the most common, and there are black, red, blue, and yellow

Color has nothing to do with quality, it is just a personalized expression

PCB boards mainly consider material and thickness, and rarely consider color. You should be talking about the color of solder mask ink! Solder mask ink colors include white, yellow, black, red, blue, and a transparent ink. The most used is green ink. The solder mask ink used is different according to the precision requirements of the board. . .

What are the specifications of PCB board materials?

The grades are divided from low to high as follows:

94HB/94VO/22F/CEM-1/CEM-3/FR-4

Detailed introduction:

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

94V0: Flame retardant cardboard (die punching)

22F: Single-sided semi-fiberglass board (die punching)

CEM-1: Single-sided fiberglass board (must be computer drilled, can not be die punched)

CEM-3: Double-sided semi-fiberglass board (except double-sided cardboard, it is the lowest-end material for double-sided board. Simple double-sided board can use this material, which is 5~10 yuan/square meter cheaper than FR-4)

FR-4: Double-sided fiberglass board

Best answer

1.c The flame retardant properties can be divided into 94V-0/V-1/V-2, 94-HB

2. Prepreg: 1080=0.0712mm, 2116=0.1143mm, 7628=0.1778mm

3. FR4 CEM-3 are all board materials, fr4 is glass fiber board, cem3 is composite substrate

4. Halogen-free refers to a substrate that does not contain halogen (fluorine, bromine, iodine and other elements), because bromine will produce toxic gases when burned, environmental protection requirements.

6. Tg is the glass transition temperature, that is, the melting point.

The circuit board must be flame-resistant and cannot burn at a certain temperature, but can only soften. The temperature point at this time is called the glass transition temperature (Tg point), and this value is related to the dimensional stability of the PCB board.

What is a high Tg PCB circuit board and the advantages of using a high Tg PCB

When the temperature of a high Tg printed board rises to a certain area, the substrate will change from "glass state" to "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 maintains rigidity. That is to say, ordinary PCB substrate materials will not only soften, deform, melt, etc. at high temperatures, but also show a sharp decline in mechanical and electrical properties (I think everyone does not want to see this situation in their own products when looking at the classification of PCB boards). Please do not copy the content of this site

Generally, the Tg of the board is above 130 degrees, the high Tg is generally greater than 170 degrees, and the medium Tg is about greater than 150 degrees.

Usually, PCB printed boards with Tg ≥ 170℃ are called high Tg printed boards.

With the increase of the Tg of the substrate, the heat resistance, moisture resistance, chemical resistance, stability resistance and other characteristics of the printed board will be improved and improved. The higher the TG value, the better the temperature resistance of the board, especially in the lead-free process, high Tg is more widely used.

High Tg refers to high heat resistance. With the rapid development of the electronics industry, especially electronic products represented by computers, the development towards high functionality and high multi-layering requires higher heat resistance of PCB substrate materials as an important guarantee. The emergence and development of high-density mounting technologies represented by SMT and CMT have made PCBs increasingly dependent on the support of high heat resistance of substrates in terms of small apertures, fine circuits, and thinness.

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

In recent years, the number of customers who require the production of high-Tg printed circuit boards has increased year by year.

PCB board knowledge and standards (2007/05/06 17:15)

At present, there are several types of copper-clad boards used in large quantities in my country. Their characteristics are shown in the following table: Types of copper-clad boards, copper-clad board knowledge

There are many ways to classify copper-clad boards. Generally, according to the different reinforcing materials of the board, it can be divided into five categories: paper base, glass fiber PCB board classification cloth base, composite base (CEM series), laminated multilayer board base and special material base (ceramic, metal core base, etc.). If the board is classified according to the different resin adhesives used, the common paper-based CCIs are: phenolic resin (XPc, XxxPC, FR-1, FR-2, etc.), epoxy resin (FE-3), polyester resin and other types. Common glass fiber cloth-based CCLs are epoxy resins (FR-4, FR-5), which are currently the most widely used glass fiber cloth-based types. In addition, there are other special resins (with glass fiber cloth, polyamide fiber, non-woven fabrics, etc. as additional materials): bismaleimide modified triazine resin (BT), polyimide resin (PI), diphenylene ether resin (PPO), maleic anhydride imide-styrene resin (MS), polycyanate resin, polyolefin resin, etc. According to the flame retardant properties of CCL, it can be divided into flame retardant types (UL94-VO, UL94- V1 grade) and non-flame retardant (UL94-HB grade). In the past one or two years, with more attention paid to environmental protection issues, a new type of CCL without bromine has been separated from the flame retardant CCL, which can be called "green flame retardant CCL". With the rapid development of electronic product technology, higher performance requirements are placed on CCL. Therefore, from the performance classification of CCL, it is divided into general performance CCL, low dielectric constant CCL, high heat resistance CCL (general board L is above 150℃), low thermal expansion coefficient CCL (generally used on packaging substrates) and other types. With the development and continuous progress of electronic technology, new requirements are constantly put forward for printed circuit board substrate materials, thereby promoting the continuous development of copper clad board standards. At present, the main standards for substrate materials are as follows.

①National standards At present, the national standards for the classification of substrate materials PCB boards in my country are GB/T4721-47221992 and GB4723-4725-1992. The copper clad board standard in Taiwan is the CNS standard, which is based on the Japanese JIS standard and was released in 1983. gfgfgfggdgeeeejhjj

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

Suppliers of original PCB design materials, the common and commonly used ones are: Shengyi\Jiantao\International, etc.

● Accepted files: protel autocad powerpcb orcad gerber or real board copy board, etc.

● Board type: CEM-1, CEM-3 FR4, high TG material;

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

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

● Maximum number of processing layers: 16Layers

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

2 pages in total:

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

● Molding size tolerance: Computer milling: 0.15mm(6mil) Mold punching: 0.10mm(4mil)

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

● Finished minimum drilling hole diameter: 0.25mm(10mil)

Finished product minimum punching hole diameter: 0.9mm(35mil)

Finished product hole diameter tolerance: PTH: +-0.075mm(3mil)

NPTH: +-0.05mm(2mil)

● Finished product hole wall copper thickness: 18-25um (0.71-0.99mil)

● Minimum SMT patch spacing: 0.15mm(6mil)

● Surface coating: chemical immersion gold, tin spraying, whole board nickel gold plating (water/soft gold), silk screen blue glue, etc.

● Thickness of solder mask on board: 10-30μm(0.4-1.2mil)

● Peel strength: 1.5N/mm (59N/mil)

● Solder mask hardness: ＞5H

● Solder mask plugging ability: 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 board warpage: < 0.7%

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

Circuit board panel specifications

1 Circuit board panel width ≤260mm (SIEMENS line) or ≤300mm (FUJI line); if automatic dispensing is required, PCB panel width × length ≤125 mm × 180 mm

2 The panel shape should be as close to a square as possible. It is recommended to use 2×2, 3×3, ... panels; but do not make yin and yang panels

3 Circuit board The outer frame (clamping edge) of the panel should adopt a closed-loop design to ensure that the PCB panel will not deform after being fixed on the fixture

4 The center distance between the small boards should be controlled between 75 mm and 145 mm

5 There should be no large or protruding devices near the connection points between the panel outer frame and the internal small boards, and between the small boards, and there should be a space of more than 0.5mm between the components and the edge of the PCB board to ensure the normal operation of the cutting tool

6 Four positioning holes are opened at the four corners of the panel outer frame, with a hole diameter of 4mm±0.01mm; the strength of the holes should be moderate to ensure that they will not break during the process of loading and unloading the boards; the hole diameter and position accuracy should be high, and the hole wall should be smooth and free of burrs

7 Each small board in the circuit board panel should have at least three positioning holes, 3≤hole diameter≤6 mm, and wiring or patching is not allowed within 1mm of the edge positioning hole

8 The reference symbol used for the whole board positioning of the circuit board and the positioning of fine-pitch devices. In principle, QFP with a spacing less than 0.65mm should be set at its diagonal position; for panel The positioning reference symbols of the circuit board should be used in pairs and arranged at the diagonal positions of the positioning elements.

9 When setting the reference positioning point, a non-resistance soldering area 1.5 mm larger than the positioning point is usually left around the positioning point.