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Have you noticed that now more and more of our lighting is using led lighting.What is LED? Compared to the traditional light bulbs, LEDs have lower power consumption, longer lifetime and higher energy efficiency. In the PCB industry,when we say LED PCB, it refers to the pcb used for LED lighting, if you are looking for a suitable LED PCB for your lighting system, this article may bring you something. WHAT ARE LEDS COMPOSED OF?LED is an initial light-emitting diode that produces light when an electric current passes through. LEDs typically have negative and positive electrodes, which generate light in the visible light region.The LEDS are glued to the PCB by soldering process and have electrical connections for lighting.Since light-emitting diodes dissipate a lot of heat when they are in use, when you are designing LED, the metal core is usually the best choice for LED PCB, it is because that it dissipates heat more faster. Among them, the metal material aluminum is the most widely used
1, plate: multi-layer board are using Shengyi /KB A-grade copper-clad plate /PP, Sun/Guangxin ink. As a recognized leading enterprise in the copper clad plate industry, Shengyi board products are used in a large number of cutting-edge PCB factories around the world, and multi-layer board guarantees the excellent performance of PCB finished products from the source. 2, hole copper :PCB production has always strictly followed the IPC secondary standard, the thinnest hole copper of the finished product is greater than 20um, beyond the IPC -- level standard! Due to good plating uniformity and strong deep plating ability,PCB dares to ensure smooth and uniform copper plating of the hole and hole wall, and there is no serious uneven copper plating similar to "10 um somewhere, 30 um somewhere" If the user finds the thinnest copper of the finished hole is less than 20um,PCB promises a full refund; 3, line width and line distance: according to the control of 20% of the soil shipment, but t
1, PCB board width ≤260mm(SIEMENS line) or ≤300mm(FUJI line); If automatic dispensing is required, PCB board width × length ≤125 mm×180 mm. 2, PCB board appearance as close as possible to the conventional graphics, it is recommended to use 2*5, 3*3 board, can be assembled according to the thickness of the board; 3. The outer frame of the PCB assembly should adopt a closed-loop design to ensure that the assembly is fixed on the fixture without deformation. 4. The center distance between the small plates is controlled between 75 mm and 145 mm. 5. There can be no large components next to the connection point between the panel shape and the PCB internal small board, small board and small board, and the edge of the components and board should have a space greater than 0.5mm. 6, four positioning holes are opened at the four corners of the outer frame of the plate, plus the Mark point, the aperture is 4mm(±0.01mm); The strength of the hole should be moderate to ensure that it will no
1. Substrate processing problems, for some thinner pcb substrates, due to poor rigidity of the substrate, it is not appropriate to use the brush machine to brush the board, and attention should be paid to control the solid production and processing, so as not to cause the poor bonding force between the substrate copper foil and chemical copper caused by the board bubbling. 2. The surface of the plate in the machining (drilling, laminating, milling, etc.) process caused by oil, or other liquids contaminated with dust pollution surface, will cause the surface foaming phenomenon. 3. The copper brush plate is bad, the grinding plate pressure is too large before copper sinking, resulting in hole deformation, so that the hole foaming phenomenon will be caused in the process of copper plating and tin-spraying welding. 4. Washing problem, due to copper plating to go through a large number of chemical solution treatment, all kinds of acid and alkali inorganic, organic and other drug solv
Cutting: According to the requirements of engineering data MI, on the large sheet plate that meets the requirements, cut into small pieces of production plate. Small sheet material that meets customer requirements. Process: Large plate material - cut plate according to MI requirements - curium plate - beer rounded or edging - out of the plate. Pressing: The pressing of the pcb four-layer board needs to go through two operations, first the inner two layers of the board after drilling, and then the outer layer and the inner layer are pressed again. Drilling: According to the engineering data (customer data), drill out the desired aperture at the corresponding position on the sheet material that meets the required size. Process: Stack pin -- top board -- drilling -- bottom board -- inspection/repair. Copper sinking: Copper sinking is the use of chemical methods on the insulation hole wall deposited on a thin layer of copper. Process: rough grinding -- hanging plate -- automatic coppe
1, the line width is wider than the fine line: because there is a fine line limit in the manufacturing process, the width is not limited. Adjusting the line width to adjust the impedance at a later stage and reach the limit can be cumbersome, which increases the cost or relaxes the impedance control. 2, there is an overall trend: there may be multiple impedance control targets in the design, so the overall size is too large or too small, and there is no need to be out of sync. 3, consider the residual copper rate and glue flow: when one or both sides of the prepreg are etched lines, during the pressing process, the glue will fill the etching gap, so the glue thickness time between the two layers is reduced. If the residual copper rate and glue flow rate are not calculated correctly, and the dielectric coefficient of the new material is not consistent with the nominal value, signal integrity problems may occur. 4, specify the glass cloth and glue content: different glue content o
Through hole (VIA), this is a common hole used for conducting or connecting copper foil lines between conductive patterns in different layers of the circuit board. Such as (e.g., blind holes, buried holes), but can not insert the component lead leg or other reinforcement material copper plated holes. Because the PCB is formed by the accumulation of many copper foil layers, each layer of copper foil will be covered with a layer of insulation layer, so that the copper foil layer can not communicate with each other, and the link of its signal depends on the through hole (via), so there is the title of the Chinese through hole. The characteristic is: in order to meet the needs of customers, the through hole of the circuit board must be strengthened, so that in changing the traditional aluminum plug process, the circuit board surface welding and plug hole are completed with white mesh, so that the production is stable, the quality is reliable, and the use is more perfect. The through h
The content of copper sulfate in each analysis in the production is low, originally divided once a week, and now in the case of excessive consumption, it is divided every day, and copper sulfate has decreased every day, originally controlled in 60-80g/L, but just added the day before, and the next day less 6-7G, I wonder why copper sulfate consumption is so large. Subsequently, according to the production volume to follow up, according to the production capacity of each shift is about 30 square meters, about 60 square meters a day, the copper consumption is about 21KG a day, a large slot of copper ball is about 1400KG, according to the production needs to consume 21KG a day, so, according to the theory, the copper ball must be added every week 147KG. After two weeks of observation, the copper ball was not replenished in time in production, and it must be replenished every week, but now it is only replenished once every two weeks. After analysis and observation, it is found that the
The so-called copper coating is to use the idle space on the PCB as the base level, and then fill with solid copper, these copper areas are also known as copper filling. The significance of copper coating is to reduce the ground impedance and improve the anti-interference ability. Reduce voltage drop, improve power efficiency; Connected with the ground wire, the loop area can also be reduced. Key words: Copper coating as an important part of PCB design, whether it is domestic Qingyufeng PCB design software, but also some foreign Protel, PowerPCB provides intelligent copper coating function, then how to apply copper, I will share some of my ideas with you, hope to bring benefits to peers. The so-called copper coating is to use the idle space on the PCB as the base level, and then fill with solid copper, these copper areas are also known as copper filling. The significance of copper coating is to reduce the ground impedance and improve the anti-interference ability. Reduce voltage
It has been said that there are only two types of electronics engineers in the world: those who have experienced electromagnetic interference and those who have not. With the increase of PCB routing, electromagnetic compatibility design is an issue that we electronic engineers have to consider. Faced with a design, there are five important attributes to consider when conducting an EMC analysis of a product and design: (1) Key device size: the physical size of the emitting device that produces radiation. The radio frequency (RF) current will generate an electromagnetic field, which will leak out of the housing through the housing. The line length on the PCB as a transmission path has a direct impact on the RF current. (2) Impedance matching: the impedance of the source and receiver, and the transmission impedance between the two. (3) The temporal nature of the interference signal: whether the problem is a continuous (periodic signal) event, or only exists in a specific operating
1, it is mentioned above that ordinary electrolytic copper foil is galvanized or copper-plated products, if the peak value of the wool foil production is abnormal, or galvanized/copper plating, the coating crystal branch is bad, resulting in the peel strength of the copper foil itself is not enough, the bad foil pressing board is made of PCB plug-in in the electronics factory, the copper wire will fall off by external impact. This kind of bad copper stripping copper wire to see the copper foil surface (that is, the contact surface with the substrate) will not be obvious side corrosion, but the peeling strength of the whole copper foil will be very poor. 2, poor adaptability of copper foil and resin: some special properties of laminates now used, such as HTg sheet, because the resin system is not the same, the curing agent used is generally PN resin, resin molecular chain structure is simple, the degree of cross-linking is low when curing, is bound to use special peak copper foil and
PCB printed circuit board drilling, the use of the upper and lower plate is to prevent the surface of the board and the bottom surface of the copper foil to produce burrs, so that the surface of the board drilling smooth improve the quality of the PCB printed circuit board, improve the yield. Due to the use of this auxiliary material has a certain cost, but due to the above reasons, it is in fact necessary to use, which can greatly improve the pass rate of the product and reduce the cost. The requirements for the board drilling are: there is a certain surface hardness to prevent burrs on the surface of the drilling. But not too hard to wear the drill. It is required that the resin composition of the upper and lower backing plate should not be too high, otherwise a molten resin ball will be formed when drilling and adhere to the hole wall. The larger the thermal conductivity, the better, so that the heat generated during drilling can be quickly taken away, reduce the temperature of
1, copper foil etching is excessive, the electrolytic copper foil used on the market is generally single-sided galvanized (commonly known as ashing foil) and single-sided plated copper (commonly known as reddened foil), the common copper is generally more than 70um galvanized copper foil, reddening foil and 18um below the ashing foil basically have not appeared batch copper. When the customer line design is better than the etching line, if the copper foil specifications are changed and the etching parameters are not changed, the residence time of the copper foil in the etching solution is too long. Because zinc is originally a active metal, when the copper wire on the PCB is soaked in the etching liquid for a long time, it will lead to excessive side corrosion of the line, causing some fine line backing zinc layer to be completely reacted off and separated from the substrate, that is, the copper wire falls off. There is also a case that there is no problem with PCB etching paramete
First, it is used as an electrical connection between the layers; The second is used as the fixing or positioning of the device. If you look at the process, these holes are generally divided into three categories, namely blind via, buried via and through via. Blind holes are located on the top and bottom surfaces of the printed circuit board and have a certain depth for the connection of the surface circuit and the inner circuit below, and the depth of the holes usually does not exceed a certain ratio (aperture). The buried hole refers to the connection hole located in the inner layer of the printed circuit board, which does not extend to the surface of the board. The above two types of holes are located in the inner layer of the circuit board, which is completed by the through hole molding process before lamination, and several inner layers may be overlapped during the formation of the through hole. The third type is called through-holes, which pass through the entire circuit boar
1, drilling parameters: the setting of drilling parameters is crucial, drilling speed is too fast back the drill bore force is too large and broken, drilling speed is too slow will reduce production efficiency. Because the PCB board thickness, copper thickness, plate structure and other conditions of the PCB board produced by the board manufacturer are not the same, the PCB needs to be set according to the specific situation. Through calculation and testing, the most suitable drilling parameters are selected. Generally, such as 0.3mm drill, the cutting speed should be 1.5-1.7m/min, and the drilling depth should be controlled between 0.5-0.8. 2, the cushion plate, aluminum drilling plate requirements moderate hardness, uniform thickness, flat, thickness difference should not exceed 0.076mm, such as the irregular distribution of the cushion plate is easy to jam the drill, the cushion plate is not smooth, will make the foot of the pressure is not strict, is the drill nozzle twisted bre
1. Prevent burrs and scratches on the surface of PCB board. 2, heat dissipation and drill cleaning function. 3, can guide the drill into the track of the PCB board to improve the accuracy of drilling. Aluminum sheet requires a large thermal conductivity, so that the heat generated during drilling can be quickly taken away, reduce the temperature of the drill, should try to use 0.15-0.2mm thick aluminum sheet or 0.15-0.35mm aluminum alloy composite aluminum sheet, effectively prevent drilling due to the high temperature caused by poor drilling chip removal and resulting in broken drill. 3, the quality of the copper clad sheet material, the glass fiber cloth of the sheet material is thick, the binding force is not good, and it will also have a greater impact on the drill break. If the resin polymerization of the plate is not complete, it is easy to produce more glue residue of the hole wall, poor chip discharge and broken drill. If there are holes in the substrate, the drill nozz
1) The diameter of the test pad specially used for detection should not be less than 0.9mm. 2) The space around the test pad should be greater than 0.6mm and less than 5mm. If the height of the component is greater than 6.7mm, the test pad shall be placed 5mm away from the component. 3) Do not place any components or test pads within 3mm of the edge of the printed circuit board. 4) The test pad should be placed in the center of a 2.5mm hole in a grid. If possible, allow the use of a standard probe and a more reliable fixture. 5) Do not rely on the edge of the connector pointer for pad testing. The gold-plated pointer is easily damaged by the test probe. 6) Avoid plating through holes - probes on both sides of the printed circuit board. Place the test tip through the hole on the non-component/weld side of the printed circuit board.
When copper plating, the low current area of the circuit board surface appears "dull" phenomenon, and the chlorine concentration is low; Generally, after adding hydrochloric acid, the "dull" phenomenon of the coating in the low current density area of the plate can disappear, the chloride ion concentration in the plating solution can reach the normal range, and the plate coating is bright. If a large amount of hydrochloric acid is added to solve the "dull" phenomenon of the coating in the low current density area, it is not necessarily caused by too low chloride ion concentration, and the real reason needs to be analyzed. If you take to add a large amount of hydrochloric acid: one, may have other consequences, two to increase production costs, is not conducive to enterprise competition. Correct analysis of "low current density area coating luster" reasons: By adding a large amount of hydrochloric acid to eliminate the "low current density area coating is not bright" phenomenon, i
Vacuum laminating machine, reduce the pressure to reduce the flow of glue, try to maintain more resin amount, because the resin affects εr, resin preservation more, εr will be lower. Control laminate thickness tolerances. Because the thickness of the PCB board is not uniform, it indicates that the change in the thickness of the medium will affect Z0. Strictly according to the customer requirements of the PCB board plate type, the model is wrong, εr is wrong, the board thickness is wrong, the manufacturing process of PCB is all right, and the same is scrapped. Because Z0 is greatly affected by εr, the finished multilayer board should try to avoid water absorption, because the εr of water = 75, which will bring a great drop and instability effect on Z0. The solder resistance of the PCB board surface will reduce the Z0 value of the signal line by 1 to 3Ω, and theoretically the solder resistance thickness should not be too thick, in fact, the impact is not very large. The surface of
The design of dynamic circuits is aimed at the repeated bending that occurs throughout the entire lifecycle of a product, such as cables for printed machines and disk drives. In order to achieve the longest bending life cycle of the dynamic circuit, the relevant parts should be designed as a single-sided circuit with copper on the central axis. The central axis refers to a theoretical plane located at the central layer of the material that makes up the circuit. By using the same thickness of substrate film and lamination on both sides of copper, the copper foil will be accurately positioned in the center and subjected to minimal pressure during bending or bending. The design of multi-layer complexity that requires high dynamic bending cycles and high density can now be achieved by using anisotropic (z-axis) adhesives to connect double-sided or multi-layer circuits to single-sided circuits. Bending only occurs in the area of single-sided assembly, and outside the dynamic bending ar
There are two different structures for circuit boards: core structure and foil structure. In the core structure, all conductive layers in the circuit board are laid on the core material; In the foil structure, only the internal conductive layer of the circuit board is applied to the core material, and the external conductive layer is made of a foil dielectric plate. All conductive layers are bonded together through a multi-layer lamination process using a medium. Nuclear materials are double-sided foil plates used in factories. Because each core has two faces, when fully utilized, the number of conductive layers on the PCB is even. Why not use foil on one side and nuclear structure on the other? The main reason is the cost of PCB and the curvature of PCB.
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