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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) One point grounding Concentrate several grounding points of the same level unit circuit as much as possible to avoid the AC signal from other circuits from entering the same level or from the AC signal in the same level from entering other circuits. Suitable for low-frequency circuits with a working frequency of less than 1MHz. If a single point grounding is used when the working frequency is between 1-1OMHz, the length of the ground wire should not exceed 1/20 of the wavelength. In short, single point grounding is the basic principle for eliminating common impedance interference of the ground wire. (2) Multiple grounding points nearby There are a large number of common ground wires distributed at the edges of the PCB and present a semi closed circuit (anti magnetic field interference). All levels of circuits are grounded nearby to prevent the ground wires from being too long. Suitable for high-frequency circuits with signal operating frequencies greater than lOMHz. (3) Groun
Mechanical characteristics of PCB through holes When the PCB through-hole is large, our wiring space will be very small. Obviously, we want to use small PCB through-holes, but how small is appropriate? Even if the PCB plate making via is already very small and the PCB plate making via is smaller, more lines can be laid on the PCB to improve the wiring density. For products with limited product size, designers have to make the PCB through holes on the board smaller and smaller. The smaller the PCB through hole, the smaller the parasitic capacitance. This means that the smaller the PCB through hole, the better it will work in high-speed situations. In the fastest PCB design, small PCB through holes are mandatory. Of course, the cost of generating small PCB through holes is higher. In engineering design, it is inevitable that the higher the performance, the higher the cost, and PCB through holes are no exception. At present, we have three principles for PCB through holes: Small PCB th
PCB process PK: tin spraying vs gold plating vs gold deposition Gold plate and gilded plate are commonly used processes in the production of circuit boards nowadays, and many people are unable to correctly distinguish the differences between the two. Some even believe that there is no difference between the two, but in fact, they are not. Usually, when people choose gold plating, what is gold plating? When we refer to whole plate gold plating, we generally refer to "electroplated gold", "electroplated nickel gold plate", "electrolytic gold", "electroplated gold", "electroplated nickel gold plate". There is a distinction between soft gold and hard gold (usually hard gold is used for gold fingers), and the principle is to dissolve nickel and gold (commonly known as gold salt) in chemical solution, Immerse the circuit board in an electroplating cylinder and apply current to generate a nickel gold coating on the copper foil surface of the circuit board. Electroplated nickel gold is wide
The difference between PCB tin spraying and PCB tin plating The cost of PCB solder board is relatively low because it only sprays tin on the PCB on the solder pad, while tin plating includes tin on the circuit as well. PCB tin plating, as the name suggests, is the process of depositing a thin layer of tin at the PCB pad location using chemical methods, usually ranging from 10 to 30 microns. The main purpose is to prevent oxidation and better fuse SMT tin. In fact, the same purpose as gold plating and OSP requires additional tin plating during SMT. PCB tin spraying refers to the physical method of spraying a layer of tin, usually ranging from 50 to 150 microns in thickness, which is relatively thick. Do not apply tin during SMT, just melt the tin onto the component. The composition of the two types of tin must be different. PCB based tin uses a salt of tin, and the mixture is an acidic solution containing tin. But PCB tin spraying generally uses tin alloys, which are generally divide
Reasons and Preventive Measures for Poor PCB Surface Mount Welding 1、 Poor wetting Poor wetting refers to the welding process where the solder and PCB substrate welding area, after being soaked, do not generate metal to metal reactions, resulting in missed or missing solder faults. The reason for this is mostly due to the surface contamination of the welding area, or the adhesion of solder resist, or the formation of a metal compound layer on the surface of the joint, such as the presence of sulfides on the surface of silver and oxides on the surface of tin, which can cause poor wetting. In addition, when the residual aluminum, zinc, cadmium, etc. in the solder exceeds 0.005%, the wetting effect of the solder reduces the activity and can also lead to poor wetting. In wave soldering, if there is gas present on the surface of the PCB substrate, this fault is also prone to occur. Therefore, in addition to implementing appropriate welding processes, anti fouling measures should be take
The automotive electronics market is the third largest application field for PCBs after computers and communication. With the gradual evolution and development of automobiles from traditional mechanical products to intelligent, information-based, mechatronics high-tech products, electronic technology has been widely used in automobiles, and electronic products have been used without exception in engine systems, chassis systems, safety systems, information systems, vehicle Internal environment systems, etc. The automotive market has clearly become another highlight of the electronic consumer market, and the development of automotive electronics has naturally driven the development of automotive PCBs. Among the key application objects of PCB today, automotive PCBs occupy an important position. However, due to the special working environment, safety, and high current requirements of automobiles, they have high requirements for the reliability and environmental adaptability of PCBs, and
The ion transport caused by electrostatic force in electroplating solution is called ion migration. The migration rate is expressed as follows: u=zeoE/6 π r η Yes. Where u is the ion migration rate, z is the charge number of the ion, and eo is the charge amount of one electron (i.e. 1.61019CE is the potential, r is the radius of the hydrated ion η Is the viscosity of the electroplating solution. According to the calculation of the equation, it can be seen that under the action of the electric field. The greater the decrease in potential E, the smaller the viscosity of the electroplating solution, and the faster the rate of ion migration. When electroplating, according to the theory of electrodeposition. The PCB located on the cathode is a non ideal polarized electrode. Copper ions adsorbed on the surface of the cathode obtain electrons and are reduced to copper atoms, resulting in a decrease in the concentration of copper ions near the cathode. Therefore, a copper ion concentratio
Anime image measuring instrument is applicable to all application fields aiming at two-dimensional measurement, and is widely used in machinery, electronics, instruments, hardware, plastics and other industries. Anime image measuring instrument (also known as image mapping instrument) is based on CCD digital image, relying on computer screen measurement technology and powerful software capabilities of spatial geometry operation. After installing specialized control and graphic measurement software, the computer becomes the measurement brain with the soul of the software and is the main body of the entire device. It can quickly read the displacement value of the optical ruler, and through software module operations based on spatial geometry, instantly obtain the desired results and generate graphics on the screen for the operator to compare the images, thus intuitively distinguishing possible deviations in the measurement results. All of this is done in real-time in front of today
Symptom: There are blasting holes in the cold or solder joints. Inspection method: Conduct regular analysis of the holes before and after immersion welding to identify areas where copper is under stress. In addition, perform incoming inspection on raw materials. Possible reasons: 1. Explosion holes or cold solder joints are seen after soldering operations. In many cases, poor copper plating can lead to expansion during soldering operations, resulting in cavities or explosive holes on the wall of the metallized hole. If this is generated during the wet processing process, the absorbed volatilization The object is covered up by the coating and then driven out under the heating effect of immersion welding, which will create a nozzle or blasting hole. Solution: 1. Try to eliminate copper stress. The expansion of laminates in the z-axis or thickness direction is usually related to the material. It can promote the fracture of metallized pores. Dealing with laminate manufacturers to
1、 Bridging The causes of bridging are mostly due to excessive solder or severe edge collapse after solder printing, or excessive PCB substrate solder area size, SMD mounting offset, etc. During the refinement stage of SOP and QFP circuits, bridging can cause electrical short circuits and affect product use. 2、 Poor wetting Poor wetting refers to the welding process where the solder and PCB substrate welding area, after being soaked, do not generate metal to metal reactions, resulting in missed or missing solder faults. The reason for this is mostly due to the surface contamination of the welding area, or the adhesion of solder resist, or the formation of a metal compound layer on the surface of the joint, such as the presence of sulfides on the surface of silver and oxides on the surface of tin, which can cause poor wetting. In addition, when the residual aluminum, zinc, cadmium, etc. in the solder exceeds 0.005%, the wetting effect of the solder reduces the activity and can al
Rare metals often need to be plated on board edge connectors, protruding contacts or gold fingers to provide lower contact resistance and higher wear resistance. This technology is called finger plating or protruding part plating. Gold is often plated on the protruding contacts of nickel plated plate edge connectors. The protruding parts of the gold finger or plate edge are manually or automatically plated. Currently, the gold plating on the contact plug or gold finger has been replaced by plating, lead plating, and button plating. The process is as follows: 1) Peel off the coating to remove tin or tin lead coating from protruding contacts 2) Rinse with cleaning water 3) Scrub with abrasive 4) Activated diffusion in 10% sulfuric acid 5) Nickel plating thickness on protruding contacts is 4-5 μ M 6) Cleaning to remove mineral water 7) Gold permeation solution treatment 8) Gilding 9) Cleaning 10) Drying
Whether the quality of PCB ink is excellent or not cannot be separated from the combination of the above major components in principle. Excellent ink quality is the comprehensive embodiment of scientific formula, progressiveness and environmental protection. This is reflected in: Viscosity is the abbreviation for dynamic viscosity. It is generally expressed in viscosity, that is, the shear stress of fluid flow divided by the Velocity gradient in the direction of the flow layer, and the International unit is Pa/s or mPa/s. In PCB production, it refers to the fluidity of ink generated by external forces. Conversion relationship of viscosity units: 1Pa. S=10P=1000mPa. S=1000CP=10dpa. s Plasticity refers to the ability of ink to maintain its pre deformation properties after being deformed by external forces. The plasticity of ink is beneficial for improving printing accuracy; Thixotropy ink is gelatinous when standing, but its viscosity changes when being touched, also known as sh
(1) Heat the waste liquid containing gold to 80-90 ℃, slowly add Iron(II) chloride solution under constant stirring, and the reaction is as follows:; Au3++3Fe2+=3Fe3++Au ↓ As the gold ions are continuously reduced, the color of the solution gradually changes from yellow to crimson, and the gold powder settles at the bottom. Continue to add excess Iron(II) oxide solution and let stand for several hours. Take two drops of static stratification solution and add two drops of 1% red blood salt. The color turns blue, indicating that the gold has been completely reduced. Pour out the upper clear liquid and filter it by vacuum method, while the lower part is precipitated with yellow gold powder. (2) Acid washing and water washing: Add a 1:2.5 hydrochloric acid solution to the gold powder and boil it, stir for 5 minutes, pour out the upper solution, and repeat this process 3-5 times until no yellow color appears. Rinse the gold powder multiple times with distilled water until the pH valu
1、 Unclear definition of processing level The single panel design is on the TOP layer, and if it is not specified, it may be difficult to assemble components on the board without proper explanation. 2、 Large area copper foil too close to the outer frame The distance between the large area copper foil and the outer frame should be at least 0.2mm, as milling onto the copper foil during contour milling can easily cause the copper foil to warp and cause the solder resist to fall off. 3、 Draw solder pads with filler blocks Drawing solder pads with filler blocks can pass DRC inspection during circuit design, but it is not feasible for machining. Therefore, this type of solder pad cannot directly generate solder mask data. When applying solder mask, the filler block area will be covered by solder mask, causing difficulty in device soldering. 4、 The electrical layer is both a solder pad and a connecting wire Because the power supply is designed as a patterned solder pad, the ground
Because there are dozens of types of CAD software popular on the market, the management of CAD processes must be first started from the organization, and good organizations will achieve more effort. Since the GERBER data format has become the standard for the optical painting industry, GERBER data should be processed in the entire optical painting process. If CAD data is used as an object, the following problems will bring. (1) There are too many types of CAD software. If all kinds of process requirements must be completed in CAD software, each operator is required to be proficient in the operation of each CAD software. This will require a long training period to make the operator a skilled worker and meet the actual production requirements. This is not cost -effective from time and economic perspective. (2) Due to the large number of process requirements, some requirements cannot be achieved for certain CAD software. Because CAD software is used for design, it is impossible to m
Computer -assisted manufacturing (CAM) is processed according to the final process. The requirements of the process mentioned earlier must make necessary preparations before light painting. For example, the problems of mirroring, welding expansion, craft lines, craft frames, line width adjustment, central holes, and appearance lines must be completed in the CAM process. In particular, it is important to note that there must be a corresponding process in the intermediate distance between the user file and must be processed accordingly. Because the process and technical level of each factory are different, to meet the ultimate requirements of the user, the necessary adjustments must be made in the production process to meet the requirements of the user's relevant accuracy. Therefore, CAM processing is an indispensable process in the manufacturing of modern printing circuits. ① Fix the size of the pad, combat D code. ② Correct the width of the line, combat D code. ③ Check the mini
1. Several temperature parameters in temperature and layer pressure are more important. That is, the melting temperature of the resin, the curing temperature of the resin, the temperature of the heat disk setting, the actual temperature of the material, and the speed of the heating. The resin starts to melt when the temperature of the melting temperature rises to 70 ° C. It is precisely because of the further increase of temperature that resin is further melted and flows. During the period of temperature of 70-140 ° C, resin is easy to fluid. It is precisely because of the popularity of the resin that it ensures that the resin fills and humidity. As the temperature gradually increases, the liquidity of the resin has gone through a small change from small to large, then small, and finally when the temperature reaches 160-170 ° C, the fluidity of the resin is 0. At this time, the temperature is called the curing temperature. In order to enable the resin to fill the glue and humidity
When the multi -layer layer is pressed, the inner core plate is required. The treatment process of the inner plate has black oxidation treatment and brown treatment process. The oxidation treatment process is to form a black oxide film on the inner copper foil, and the thickness of the black oxide film is 0.25-4). 50mg / cm2. The brown treatment process (horizontal brownization) forms a layer of organic membrane on the inner copper foil. The inner plate processing process is: 1. Increase the surface of the inner copper foil and resin to enhance the combination between the two. 2. Increase the effective and moistness of copper foil when the melting resin flows, so that the flowing resin has sufficient ability to extend the oxidation film, and show a strong grip after solidification. 3. Stop the impact of the decomposition of anemia in the liquid resin at high temperature at high temperature. 4. Make multi -layer boards improve acid resistance and prevent pink circle in the wet p
PCB line board price analysis PCB price consists of the following factors: 1. The materials used in PCB line boards are different Taking ordinary double panels as an example, plate materials generally include FR-4, CEM-3, etc., the thickness of the board ranges from 0.6mm to 3.0mm, and the copper thickness is different from ½OZ to 3 OZ. In terms of welding ink, there is a certain price difference in ordinary thermal solid oil and light sensitive green oil. 2. PCB uses different production processes Different production processes will cause different costs. For example, the gold -plated board and tin spray plate, making the gong (milling) board and beer (punch) board, the use of silk print lines and dry membrane lines will form different costs. Third, the PCB line board itself is difficult to be different Even if the materials are the same and the craftsmanship, the difficulty of PCB itself will cause different costs. For example, there are 1,000 holes on both line boards, and
PCB copper -covering board grade division 1. FR-4 A1 Copper Copy Copper Board This class is mainly used in electronic products such as military industry, communication, computers, digital circuits, industrial instruments, automotive circuits and other electronic products. The quality of this series of products has completely reached the world -class level, and it is the company with the highest grade and best performance. 2. FR-4 A2 Copper Cover Copper Plate. This level is mainly used for ordinary computers, instrumentations, senior home appliances and general electronic products. This series of copper -covering plates are widely used, and various performance indicators can meet the needs of general industrial electronic products. There is a good price performance ratio. Can enable customers to effectively improve price competitiveness. 3. FR-4 A3 Copper Crystal Copper Copper is a FR-4 product developed and produced for the company's home appliance industry, computer peripheral pr
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