Keyword: pcb board, circuit board, PCB substrate materials
PCB board is introduced: according to the brand quality level from the bottom to the high classification is as follows: 94 hb - 94 vo - 22 f - CEM - 1 - CEM - 3 - FR - 4
Detailed parameters and USES are as follows:
94 hb: ordinary cardboard, do not fire (the most cheap material, punching mould, cannot do the power board)
94 where v0: flame retardant board (die punching)
22 f: single half glass fiber board (die punching)
CEM 1: single glass fiber board (must drill computer, not die)
CEM - 3: half a double-sided glass fiber board (except the double-sided board belongs to the bottom material double panel, simple double panel can use this kind of material, cheaper than FR - 4 will be 5 ~ 10 yuan/square meters)
FR - 4: double glass fiber board
Flame retardant properties of hierarchies can be divided into vo - 94 - V V - 1-2-94 hb
Half cure piece: = 0.0712 1080 mm, 1080 = 0.1143 mm, 7628 = 0.1778 mm
FR4 CEM - 3 are said plank, FR4 is glass fiber board, cem3 is composite substrate
Halogen free refers to do not contain halogen bromine, iodine, fluorine and other elements) of the base material, because of bromine in combustion would produce the toxic gas, environmental protection requirements.
Tg is the glass transition temperature, the melting point.
Circuit board must be fire resistant, couldn't burn at certain temperatures, can only be soften. When the temperature of the point is called the glassy state transformation temperature (Tg), the value is related to the durability of the size of the PCB.
What is the high Tg PCB circuit boards and the advantages of using high Tg PCB
High Tg printed circuit board when the temperature rises to a threshold substrate will by "glassy state" into "rubber", the temperature at this point is called the plate glass transition temperature (Tg). That is to say, the Tg is to maintain the rigidity of base material the highest temperature (℃). That is common PCB substrate material at high temperature, produce the phenomenon such as softening, deformation, melting, also reflected in the sharp decline in mechanical, electrical properties, like this will affect the service life of the product, generally Tg board for more than 130 ℃, high Tg generally greater than 170 ℃, medium Tg is greater than 150 ℃; Tg of 170 ℃ or more usually PCB, called high Tg PCB; Substrate of Tg raised, PCB heat resistance, moisture resistance, chemical resistance, resistance to stability characteristics will improve and improve. The higher the TG values, plate temperature resistant performance is good, especially in the lead-free process, high TG application more; High Tg refers to the high heat resistance. With the rapid development of electronic industry, especially the electronic products represented by computer, toward high function, high multiple stratification, need PCB substrate material of higher heat resistance as a prerequisite. Represented by SMT, CMT's emergence and development of high density installation technology, make the PCB in the small aperture, fine lines, thin, more and more inseparable from the support substrate, high heat resistance.
So the difference between the average FR - 4 and high Tg: high temperature, especially in the heat after moisture absorption, its material mechanical strength, dimensional stability, adhesion, water absorption, thermal decomposition, thermal expansion situations vary, such as high Tg products is significantly better than the ordinary PCB substrate materials.
PCB board knowledge and standard at present, the extensive use of coated copper has the following several types, its features are as follows: apply copper plate type, apply the knowledge of copper, the copper-clad plate has a variety of classification method. To press plate reinforced material, can be divided into: base paper, glass fiber cloth, composite base (CEM), laminated sandwich plate and special materials (ceramics, metal core, etc.) the five classes. If adopted by the press plate to categorize different resin adhesives, common paper-based CCI. Are: phenolic resin (XPc, XxxPC, FR - 1, 2, etc.) FR a, epoxy resin (FE 3), polyester resin and other types. A common glass fiber cloth CCL has an epoxy resin (FR a 4, FR - 5), it is currently the most widely used type of glass fiber cloth base. Other speciality resin (with glass fiber cloth, nylon, non-woven, etc to increase the material) : double maleic imide (BT), polyimide resin modified triazine resin (PI), diphenylene ether resin (PPO), maleic anhydride imide - styrene resin (MS), poly (cyanate ester resin, polyolefin resin, etc. According to CCL flame retardant performance classification, can be divided into flame retardant (UL94 a VO, UL94 V1) and non flame retardant (UL94 HB level) two types of boards. Nearly two years, with the increased attention given to environmental issues, in the flame retardant CCL and gives a new kind of doesn't contain bromine varieties of CCL class content, can be referred to as the "green flame retardant CCL". With the rapid development of electronics technology, the cCL have higher performance requirements. From the performance of the CCL classification, therefore, is divided into general performance CCL CCL, low dielectric constant, high heat resistance of CCL (general plate L at above 150 ℃), low thermal expansion coefficient of CCL (generally used to encapsulate the substrate), and other types. With the development of electronic technology and continuous improvement, substrate material continuously put forward new requirements for printed circuit board, thereby, to promote the continuous development of copper-clad plate standards. At present, the substrate material of the main standards as follows.
(1) national standards on substrate materials in China national standard GB/T4721-47221992 and GB4723-4725-4725, the Chinese Taiwan area of copper-clad plate for CNS standard, is Japan's JIs standard is drawn up a blueprint, released in 1983. gfgfgfggdgeeeejhjj
(2) international standard: Japan JIS standards, American ASTM, NEMA, MIL, IPc, ANSI, UL, British Bs standard, the German DIN, VDE standards, France's NFC, UTE standards, Canadian CSA standard, Australia AS the standard, the former Soviet union FOCT standards and international IEC standards, etc.; Supplier of PCB design material, common and common to have: profit, build out, such as international
Low accept files: protel autocad powerpcb orcad gerber or solid board copy board, etc
Low plate type: CEM 1, CEM - 3 FR4, high TG material;
Low biggest panel size: 600 mm * 700 mm (24000 mil * 27500 mil)
Low processing plate thickness: 0.4 mm to 0.4 mm (15.75 mil) 15.75 mil -
Low top processing layer: 16 the layers
Low copper foil thickness: 0.5 4.0 (oz)
Low finished product thickness tolerance: + / - 0.1 mm (4 mil)
Low molding size tolerance: computer milling: 0.15 mm (6 mil) mold impact: 0.10 mm (4 mil)
Low minimum line width/span: 0.1 mm (4 mil) control of line width: < + - 20%
Low finished product minimum borehole diameter: 0.25 mm (10 mil)
Low finished product minimum punching diameter: 0.9 mm (35 mil)
Low finished product size tolerance, PTH: + 0.075 mm (3 mil)
Low NPTH: + 0.05 mm (2 mil)
When finished hole wall copper thickness: 18 to 25 um (0.71 0.99 mil)
Low minimum SMT spacing: 0.15 mm (6 mil)
Low surface coating, chemical heavy gold, tin, the whole plate nickel plating gold (water/soft gold), silk-screen printing LanJiao, etc
Low on resistance welding plate film thickness: 10 to 30 microns (0.4 1.2 mil)
Low peel strength: 1.5 N/mm N/mil (59)
Low resistance welding film hardness: > 5 h
Low resistance welding plug hole capacity: 0.3 to 0.8 mm (12 mil - 30 mil)
Low dielectric constant: epsilon = 2.1 to 10.0
Low insulation resistance: 10 k Ω Ω - 20 m
Low characteristic impedance: 60 ohm + / - 10%
Low thermal shock: 288 ℃, 10 SEC
Low finished product board warp degrees: < 0.7%
Low product application: communication equipment, automotive electronics, instrumentation, global positioning system (GPS), MP4, computer, power supply, home appliance, etc
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WEIKU PCB is shenzhen huaqiang group provides professional circuit board sample, clapper talk and batch production of high-tech enterprises.
The company is committed to the high precision of single, double side, multi-layer circuit board manufacturing, for the domestic and foreign high-tech enterprises, scientific research units and electronic products provide high quality products and services.
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