+86 755 2794 4155 
sales@knownpcb.com
Circuit board plate grade and grade introduction According to the grade level from bottom to high divided as follows: 94HB/94VO/22F/CEM-1/CEM-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 (in addition to double-sided cardboard is the lowest end of the double-panel material, simple double-panel can be used with this material, than FR-4 will be cheaper 5~10 yuan/square meter) FR-4: double-sided fiberglass board
Introduction to aluminum substrate First, the characteristics of LED aluminum substrate 1. Use external mount technology (SMT); 2. Extremely useful treatment of thermal diffusion in circuit design schemes; 3. Reduce the operating temperature of the commodity, improve the power density and reliability of the commodity, and extend the service life of the commodity; 4. Reduce the volume of goods, reduce the hardware and installation costs; 5. Replace the fragile ceramic substrate to achieve very good mechanical durability. Second, the layout structure of LED aluminum substrate Aluminum clad copper plate is a metal circuit board data, composed of copper foil, thermal insulation layer and metal substrate, its layout is divided into three layers: Line layer: equivalent to the copper clad plate of the usual PCB, line copper foil thickness loz to 10oz. Insulation layer: Insulation layer is a layer of low thermal resistance thermal insulation material. BaseLayer substrate: A metal
According to the grade level from bottom to high divided as follows: 94HB/94VO/22F/CEM-1/CEM-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 (in addition to double-sided cardboard is the lowest end of the double-panel material, simple double-panel can be used with this material, than FR-4 will be cheaper 5~10 yuan/square meter) FR-4: double-sided fiberglass board
Introduction to aluminum substrate First, the characteristics of LED aluminum substrate 1. Use external mount technology (SMT); 2. Extremely useful treatment of thermal diffusion in circuit design schemes; 3. Reduce the operating temperature of the commodity, improve the power density and reliability of the commodity, and extend the service life of the commodity; 4. Reduce the volume of goods, reduce the hardware and installation costs; 5. Replace the fragile ceramic substrate to achieve very good mechanical durability. Second, the layout structure of LED aluminum substrate Aluminum clad copper plate is a metal circuit board data, composed of copper foil, thermal insulation layer and metal substrate, its layout is divided into three layers: Line layer: equivalent to the copper clad plate of the usual PCB, line copper foil thickness loz to 10oz. Insulation layer: Insulation layer is a layer of low thermal resistance thermal insulation material. BaseLayer substrate: A metal
Single panel features The single panel is on the most basic PCB, the parts are concentrated on one side, and the wires are concentrated on the other side. Because the wire only appears on one side, we call this PCB Single-sided. Because a single panel has many strict restrictions on the design circuit (because there is only one side, the wiring can not cross and must go around a separate path), only early circuits used such boards; The wiring diagram of the single panel is mainly Screen Printing, that is, the resistance is printed on the copper surface, and then the welding resistance is etched to prevent the mark, and finally the pilot hole and the shape of the part are completed by punching. In addition, some of the products produced in small quantities and in a variety of ways, the photographic method of pattern formation with photoresist is used.
Double-sided circuit board Double-Sided Boards have wiring on both sides. However, in order to use the wires on both sides, there must be a proper circuit connection between the two sides. This "bridge" between circuits is called a pilot hole (via). A pilot hole is a small hole filled with or coated with metal on the PCB, which can be connected with wires on both sides. Because the area of the dual panel is twice as large as that of the single panel, and because the wiring can be interlaced (can be wound around the other side), it is more suitable for use in more complex circuits than the single panel. Strictly speaking, double panel is a very important PCB board in the circuit board, its use is very simple to see whether a PCB board is double panel, I believe that friends' understanding of the single panel is completely able to grasp, double panel is an extension of the single panel, meaning that the single panel line is not enough to turn to the opposite, Another important featur
Due to the increase in the package density of integrated circuits, the interconnection is highly concentrated, which makes the use of multi-substrate necessary. In the layout of printed circuits, unforeseen design problems arise, such as noise, stray capacitance, crosstalk, etc. Therefore, the printed circuit board design must be committed to minimizing the length of the signal line and avoiding parallel routes. Obviously, in a single panel, or even a dual panel, none of these needs can be satisfactorily answered due to the limited number of intersections that can be achieved. In the case of a large number of interconnect and cross requirements, the board must be expanded to more than two layers in order to achieve a satisfactory performance, thus the emergence of multi-layer circuit boards. Therefore, the original intention of manufacturing multilayer circuit boards is to provide more freedom to choose the appropriate routing path for complex and/or noise-sensitive electronic ci
Flexible circuit board definition is also called flexible printed circuit board, or soft printed circuit board. According to IPC's definition, flexible printed circuit board is a product that is designed and made of circuit graphics on a flexible substrate in a printed manner. Flexible circuit board advantages Flexible printed circuit board is an important type of PCB. Its characteristics are: (1) FPC has small size and light weight. (2) FPC can move, bend and twist. (3) FPC has excellent electrical properties, dielectric properties and heat resistance. (4) FPC has high assembly reliability and assembly operability. (5) The FPC can be installed with a three-position connection. (6) FPC is beneficial to thermal diffusion. (7) Low cost. (8) Continuity of processing. Cause of silver layer of circuit board By analyzing the root cause of the defects, these defect rates can be minimized through a combination of process improvement and parameter optimization. The Giavani effec
PCB wave soldering In order to ensure that the surface of the board and the surface of the lead are quickly and completely soaked by solder, the flux must be coated. Generally, rose-scented flux or water-soluble flux with a relative density of 0.81 ~ 0.87 is used. ② The PCB circuit board coated with flux should be preheated, which should generally be controlled at 90 ~ 110℃. A good grasp of the preheating temperature can reduce or avoid the occurrence of pointed and round solder joints. ③ In the welding process, the solder temperature should generally be controlled within the range of 250 ° C ±5 ° C, and whether the temperature is suitable for directly affecting the welding quality; The Angle of inclination of the welding fixture into the crest should be adjusted to 6. Around; The welding speed should be mastered at 1 ~ 1.6n/min; Solder groove tin surface crest height is about lOmm, the peak is generally controlled in the board thickness of 1/2 ~ 213, too large will lead to molten
PCB manual welding ① Check the insulation materials in advance before welding, and there should be no burns, scorches, deformation, cracks and other phenomena, and do not allow burns or damage to components during welding. The welding temperature should usually be controlled at about 260 ° C, not too high or too low, otherwise it will affect the welding quality. ③ The welding time is usually controlled within 3s. For welding parts with large heat capacity such as multi-layer plates, the entire welding process can be controlled within 5s; For the welds of integrated circuits and thermal components, the entire process should not exceed 2s. If it is not welded well within the specified time, it should be re-welded after the welding joint has cooled, and the quality standard of re-welding should be the same as that of the welding joint during a single welding. Obviously, due to the differences in the power of the soldering iron, the heat capacity of the solder joint and other factors,
Component layout principles in PCB design 1) General principle: If the circuit system has both digital circuits and analog circuits. As well as the high-current circuit, it must be arranged separately, so that the coupling between the systems reaches the minimum in the same type of circuit, according to the signal flow and function, the block, the partition of the components. 2) Input signal processing unit, output signal driver should be close to the board side, so that the input and output signal line as short as possible to reduce input and output interference. 3) Component placement direction: components can only be arranged in two directions: horizontal and vertical. Otherwise it is not good for the plug-in. 4) Component spacing. For medium density boards, small components such as low-power resistors, capacitors, Diodes, such as discrete components of each other and plug-in, welding process related, peak welding, component spacing can take 50-100MIL(1.27--2.54MM) manual can
PCB gold plate oxidation The oxidation of the submerged gold plate is the contamination of the gold surface by impurities, and the impurity attached to the gold surface changes color after oxidation, which leads to the gold surface oxidation that we often say. In fact, the gold surface oxidation statement is not accurate, gold is an inert metal, under normal conditions will not occur oxidation, and impurities attached to the gold surface such as copper ions, nickel ions, microorganisms in the normal environment is easy to oxidize to form gold surface oxides. Through observation, it is found that the oxidation of gold plate has the following characteristics: 1, improper operation causes pollutants to adhere to the gold surface, such as: with unclean gloves, finger cover contact with gold surface, gold plate and unclean table, pad contact pollution; Such oxidation area is large, may appear on multiple adjacent pads at the same time, and the appearance color is lighter and easier to
Thermal stability of PCB materials The content of nitrogen and phosphorus in halogen-free plate is higher than that of common halogen-based material, so the monomer molecular weight and Tg value are increased. In the case of heat, the molecular movement capacity will be lower than that of conventional epoxy resins, so the coefficient of thermal expansion of halogen-free materials is relatively small. Compared with halogen-free plate, halogen-free plate has more advantages, and halogen-free plate replaces halogen-free plate is also the trend of The Times. Five, the production of halogen-free PCB experience 1 ply Laminating parameters may vary from company to company. Take the above mentioned Sheng benefit substrate and PP multi-layer board, in order to ensure the full flow of resin, so that the binding force is good, the requirements of low plate heating rate (1.0-1.5℃ / min) and multi-stage pressure coordination, and in the high temperature stage requires a longer time, 180℃ to m
PCB halogen-free plate characteristics 1 Insulation of the material Due to the use of P or N to replace the halogen atoms, the polarity of the molecular bond segment of the epoxy resin is reduced to a certain extent, so as to improve the insulation resistance and resistance to penetration. 2 Water absorption of the material Because the N and P foxes in the nitrogen and phosphorus REDOX resin are less electron than the halogen, the probability of hydrogen bond formation with the hydrogen atom in water is lower than that of the halogen material, so the water absorption of the material is lower than that of the conventional halogen flame retardant material. For the plate, low water absorption has a certain impact on improving the reliability and stability of the material.
Why should PCB ban halogen Halogen: Halogen elements in the periodic table of chemical elements, including fluorine (F), chlorine (Cl), bromine (Br), iodine (I). At present, flame retardant substrates, FR4, CIM-3, etc., and flame retardants are mostly brominated epoxy resins. Studies by relevant institutions have shown that halogene-containing flame retardant materials (polymerized polybrominated biphenyls PBB: Polybrominated diphenyl ether PBDE (PBDE), when discarded and burned, will release dioxin Dioxin TCDD, Benzfuran (Benzfuran), etc., large smoke, odor, highly toxic gas, carcinogenic, can not be discharged after human intake, seriously affecting health. Therefore, the EU law prohibits the use of six substances such as PBB and PBDE. The same document of China's Ministry of Information Industry requires that electronic information products put on the market cannot contain lead, mercury, hexvalent chromium, polybrominated biphenyls or polybrominated diphenylethers and other subst
The most commonly used dual-head laser drilling system is the hybrid laser drilling system, which consists of an ultraviolet laser head and a CO2 laser head. This integrated hybrid laser drilling method can be used to drill copper and dielectric simultaneously. Using ultraviolet light, copper is drilled to generate the size and shape of the desired hole, followed by an open dielectric drilled with a CO2 laser. The drilling process is done by drilling a 2in X 2in block called a domain. CO2 lasers effectively remove dielectrics, even non-uniform glass-reinforced dielectrics. However, a single CO2 laser cannot make small holes (less than 75μm) and remove copper, with a few exceptions, it can remove pre-treated thin copper foils below 5μm (lustino, 2002). The UV laser is capable of making very small holes and can remove all ordinary copper street (3-36μm, 1oz, even electroplated copper foil). The ultraviolet laser can also remove the dielectric material alone, but at a slower rate. Mo
Problems related to holes in circuit board design 1, from the two aspects of cost and signal quality, choose a reasonable size of the hole size. For example, for 6-10 layers of memory module PCB, it is better to choose 10/20Mil (drill/pad) through holes, and for some high-density small-size boards, you can also try to use 8/18Mil through holes. Under current technical conditions, it is difficult to use a smaller size of the hole. For the power supply or ground wire hole, you can consider using a larger size to reduce the impedance. 2, the use of a thinner PCB board is conducive to reducing the two parasitic parameters of the hole. 3, the signal on the circuit board as far as possible not to change the layer, that is to say, try not to use unnecessary holes. 4. The pins of the power supply and the ground should be punched in the nearest hole, and the shorter the lead between the hole and the pin, the better, because they will lead to an increase in inductance. At the same time, th
High frequency circuit board in the wiring design should pay attention to matters 1) Reasonable selection of the number of layers in the PCB design of the high-frequency circuit board wiring, the use of the middle inner layer plane as a power supply and ground layer, can play a shielding role, effectively reduce the parasitic inductance, shorten the length of the signal line, reduce the cross interference between signals, under normal circumstances, the four-layer board than the two-layer board noise is 20dB lower. 2) Wiring mode When wiring the high-frequency circuit board in the PCB design, the wiring must be turned in accordance with a 45° Angle, which can reduce the transmission of high-frequency signals and the coupling between each other. 3) Line length When routing high-frequency circuit boards in PCB design, the shorter the line length, the better, and the shorter the parallel distance between two lines, the better. 4) The number of holes in the PCB design of the high-fre
PCB production process PCB production process is more complex, it involves a wide range of processes, from simple machining to complex machining, there are ordinary chemical reactions and photochemical electrochemical thermochemistry and other processes, computer-aided design CAM and other aspects of knowledge. Moreover, in the production process, there are many process problems and new problems will be encountered from time to time, and some problems will disappear without finding out the cause. Because the production process is a non-continuous form of assembly line, any problem in any link will cause the whole line to stop production or a large number of scrapped consequences. If the printed circuit board is scrapped, it can not be recycled. The job of process engineer is stressful, so many engineers leave the industry to work in sales and technical services for PCB equipment or materials manufacturers. The substrate of the board itself is made of an insulating, non-bendable mat
Soft board FPCB material characteristics The product characteristics of soft board FPCB, in addition to the soft material, in fact, there is a light texture, the configuration is very thin/very light structure, the material can be bent several times without breaking the insulation material of hard PCB, and the soft plastic substrate and wire layout of the soft board, so that the soft board can not cope with too high conduction current and voltage. Therefore, in high-power electronic circuit applications, you can hardly see the soft board design, but in small current, small power consumer electronic products, the use of soft board is quite large. Because the cost of the soft board is still subject to the key material PI, the unit cost is high, so in the product design, usually not to use the soft board as the main carrier board, but locally apply the key design that requires "soft" characteristics, such as the soft board application of the electronic zoom lens of the digital camera,
About Us Product Center Capabilities&Applications Quality Assurance News Contact Us flexible printed circuit board
ISO 9001:2008 registered © 2022 Shenzhen Knownpcb Technology Co., Ltd. All Rights
Reserved ICP: 粤ICP备08036040
Inquiry Now
EN
CN
中文
Home > 
