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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
Electromagnetic compatibility refers to the ability of electronic devices to work in a coordinated and effective manner in various electromagnetic environments. The purpose of electromagnetic compatibility design is to enable electronic devices to suppress various external interferences, enabling them to operate normally in specific electromagnetic environments, while also reducing the electromagnetic interference of electronic devices themselves on other electronic devices. Choose a reasonable wire width. The impact interference generated by transient current on printed lines is mainly caused by the inductance component of printed wires, so the inductance of printed wires should be minimized as much as possible. The inductance of printed wires is directly proportional to their length and inversely proportional to their width, so short and precise wires are beneficial for suppressing interference. The signal lines of clock leads, row drivers, or bus drivers often carry large trans
Correctly selecting single point grounding and multi-point grounding in low-frequency circuits, where the operating frequency of the signal is less than 1MHz, the wiring and inductance between devices have less impact, while the circulating current formed by the grounding circuit has a greater impact on interference. Therefore, single point grounding should be used. When the operating frequency of the signal is greater than 10MHz, the impedance of the ground wire becomes large. At this time, the impedance of the ground wire should be reduced as much as possible, and nearby multi-point grounding should be used. When the working frequency is between 1-10MHz, if a single point grounding is used, the length of the ground wire should not exceed 1/20 of the wavelength. Otherwise, the multi-point grounding method should be used. Separate digital circuits from analog circuits. If there are both high-speed logic circuits and linear circuits on the circuit board, they should be separated as
In the PCB process flow, the reservation of process edges is of great significance for subsequent SMT surface mount processing. The process edge is to assist in the production of plug-in boards, and the part where welding peaks are added on both sides or four sides of the PCB board, mainly to assist production. It is not a part of the PCB board and can be removed after production is completed. Due to the fact that process edges consume more PCB boards and increase the overall cost of PCBs, it is necessary to balance economy and feasibility when designing PCB process edges. For some special shaped PCB boards, the original PCB boards with 2 or 4 process edges can be cleverly simplified by splicing. When designing the splicing method in SMT mounting processing, it is necessary to fully consider the track width of the SMT mounting machine. For splicing exceeding 350mm in width, it is necessary to communicate with the SMT supplier's process engineer. The main reason for leaving proces
Laser processing technology is a technology that utilizes the characteristics of the interaction between laser beams and materials to cut, weld, surface treat, drill holes, micro process materials (including metals and non-metals), and use them as light sources to identify objects. The traditional application of laser processing technology is the largest field. Laser technology is a comprehensive technology that involves multiple disciplines such as optics, mechanics, electronics, materials, and detection. Traditionally, its research scope can generally be divided into: 1. Laser processing system. Including lasers, light guiding systems, machining machines, control systems, and detection systems. 2. Laser processing technology. Including various processing techniques such as cutting, welding, surface treatment, drilling, marking, marking, and fine tuning. Laser welding: Sealing devices such as thick and thin sheets of automotive body, automotive parts, lithium batteries, pacemak
Question 1: What is part packaging and what is the difference between it and parts? Answer: (1) Part packaging refers to the appearance and solder joint position indicated when the actual part is soldered onto the circuit board. (2) Part packaging is only the appearance and solder joint position of the part, and pure part packaging is only a concept of space, so different parts can share the same part packaging; On the other hand, the same type of part can also have different packaging, such as RES2 representing resistance, which has packaging forms such as AXAIL0.4, AXAIL0.3, AXAIL0.6, etc. Therefore, when using welded parts, it is not only necessary to know the part name but also the packaging of the part. (3) The packaging of parts can be specified during circuit design or when introducing network tables. When designing a circuit diagram, you can specify it in the Footprint settings in the Part Properties dialog box, or you can also specify the part packaging when importing a
For a newly designed circuit board, debugging often encounters some difficulties, especially when the PCB board is relatively large and there are many components, making it difficult to start. But if you master a reasonable set of debugging methods, debugging will be twice the result with half the effort. For newly retrieved PCB boards, we first need to roughly observe whether there are any problems on the PCB board, such as obvious cracks, short circuits, open circuits, etc. If necessary, check if the resistance between the power supply and the ground wire is large enough. Then it's time to install the components. It is best not to install all modules that are independent of each other when you are not confident in ensuring their normal operation. Instead, you should install them part by part (for smaller circuits, you can install them all at once), which can easily determine the scope of the fault and avoid being unable to start when encountering problems. Generally speaking, th
Hot air leveling is the process of immersing a printed circuit board into molten solder (63SN/37PB), and then using hot air to blow off excess solder from the surface and metalized holes of the printed circuit board, resulting in a smooth, uniform, and bright solder coating layer. The lead tin alloy coating on the surface of the printed circuit board after hot air leveling should be bright, uniform, and complete, with good solderability, no nodules or semi wetting, and the coating should be completely free of exposed copper. Copper exposure on the surface and metalized holes of the solder pad after hot air leveling is an important defect in finished product inspection, and is one of the common causes of hot air leveling rework. There are many reasons that can cause this problem, including the following. 1. Insufficient pre-treatment and poor coarsening. The quality of the pre-treatment process for PCB hot air leveling has a significant impact on the quality of hot air leveling. T
⑴ Differences in longitude and latitude directions cause changes in substrate size; Due to the lack of attention to fiber direction during shearing, shear stress remains in the substrate, and once released, it directly affects the shrinkage of the substrate size. The copper foil on the surface of the substrate is etched off, which limits the variation of the substrate and results in dimensional changes when stress is relieved. When brushing the board, excessive pressure is used, resulting in compressive and tensile stresses that cause deformation of the substrate. The resin in the substrate is not completely cured, resulting in size changes. Especially for multi-layer boards, poor storage conditions before lamination can cause moisture absorption on thin substrates or semi cured sheets, resulting in poor dimensional stability. When the multi-layer board is pressed, excessive glue flow causes deformation of the glass cloth. Solution: ⑴ Determine the variation pattern of longi
In the manufacturing process of printed circuit boards, there are many processes involved, and each process may have quality defects. These quality issues always involve many aspects, which can be difficult to solve. As the causes of problems are multifaceted, some belong to chemical, mechanical, sheet metal, optical, and other aspects. After decades of production practice, combined with practical experience in solving quality problems and relevant information on solving technical problems, the following summary is made: Defects, causes, and solutions in the manufacturing process of printed circuit boards Solution to the causes of defects in the process There are blisters on the facial mask layer of the film sticking board. The board surface is not clean. Check the wettability of the board surface, that is, the clean surface can keep the water even and the continuous water film lasts for up to 1 minute Low film temperature and pressure increase temperature and pressure The edg
A single panel is on the most basic PCB, with parts concentrated on one side and wires concentrated on the other side. Because wires only appear on one side, we call this type of PCB a single side. Because single panels have many strict limitations in designing circuits (because they are only on one side, wiring cannot cross and must follow separate paths), only early circuits used such boards; The wiring diagram of a single panel is mainly based on screen printing, which means printing a resist on the copper surface, etching it, then marking it with solder mask, and finally completing the part guide hole and shape through punching processing. In addition, some products produced in small quantities are photographed using photosensitive agents to form patterns. Double sided boards have wiring on both sides. However, to use wires on both sides, there must be appropriate circuit connections between the two sides. The bridge between these circuits is called a guide hole (via). A guid
Strictly speaking, PCB double-sided board is a very important type of PCB board in the circuit board. It has a wide range of uses, and it is easy to check whether a PCB board is a double-sided board. I believe that friends can fully grasp the understanding of single panels. Double panels are the extension of single panels, which means that the circuit of single panels is not enough to turn to the opposite side. Another important feature of PCB double-sided boards is that they have conductive holes. Simply put, it means double-sided wiring, with lines on both sides! A summary is: A board with double-sided wiring is a double-sided board! Some friends may ask, for example, if a board has double-sided wiring but only one side has electronic components, is it a double-sided board or a single panel? The answer is obvious, such a board is a double-sided board, only parts are installed on the board of the double-sided board. The advantages of manufacturing PCB double-sided boards are tha
1、 Firstly, considering whether it is a customer design issue, check if there is a connection method between the solder pad and the copper sheet that may cause insufficient heating of the solder pad. 2、 Are there any issues with customer operations. If the welding method is incorrect, it will affect the insufficient heating power, temperature, and contact time. 3、 Improper storage issues. 1. Under normal circumstances, the tin sprayed surface will completely oxidize or even be shorter in about a week 2. The OSP surface treatment process can be stored for about 3 months 3. Long term preservation of sunken gold plates 4、 The issue with flux. 1. Insufficient activity to completely remove oxidation substances from PCB pads or SMD solder joints 2. Insufficient amount of solder paste at the solder joint and poor wetting performance of the flux in the solder paste 3. Part of the solder joints may not be fully filled with solder, which may result in insufficient mixing of the flux
1: The process flow of selective welding includes: flux spraying, circuit board preheating, immersion welding, and drag welding. The flux coating process plays an important role in selective welding. When welding is heated and completed, the flux should have sufficient activity to prevent bridging and oxidation of the circuit board. The flux spraying is carried by an X/Y robotic arm above the flux nozzle on the circuit board, Spray flux onto the soldering position of the double-sided circuit board. 2: The most important aspect of microwave peak selection welding after reflow soldering is accurate flux spraying. Micro hole spraying will never contaminate the area outside the solder joint. Micro point spraying has a minimum flux point pattern diameter greater than 2mm, so the precision of the flux position deposited on the circuit board is ± 0.5mm to ensure that the flux always covers the soldered area. 3: The process characteristics of selective soldering can be understood by comp
Among them, the most common four layer PCB board thickness in Tongling is 1.6mm, and four layer boards above 3.0mm are relatively rare. Customized 0.6-3.5mm thick PCB boards are supported. The four layer board lamination diagram shows that for a 1.6mm thick PCB, the top layer is 1 ounce of copper, followed by a (0.2mm-0.5oz) thick PP sheet, followed by a second signal layer with a copper foil thickness of only 0.5 ounces, followed by a (1.2mm-0.5OZ) thick core layer, and the bottom layer is a 0.2mm thick PP sheet, Finally, there is a 1 ounce bottom layer. The 6-layer board is similar. PP sheet and core board: Prepregs are thin insulation materials for PCBs. Prepregs, also known as pre impregnated materials, are mainly used as adhesive and insulating materials for the inner conductive patterns of multi-layer printed boards before being laminated. After being laminated, the semi cured epoxy resin is squeezed out, begins to flow and solidify, bonding the multi-layer circuit boards to
The so-called ceramic circuit board is a type of thermal conductive organic ceramic circuit board prepared using thermal conductive ceramic powder and organic adhesive, with a thermal conductivity coefficient of 9-20W/m.k under conditions below 250 ℃. Ceramic circuit boards are mainly used in areas such as high voltage, high insulation, high frequency, high temperature, high reliability, and small volume electronic products. 1. High precision clock oscillator, voltage controlled oscillator, temperature compensated oscillator ceramic circuit board. 2. Metallization of ceramic substrates for refrigerators. 3. Metallization of ceramic substrates for surface mounted inductors. Metallization of Inductive Magnetic Core Electrodes. 4. High insulation and high voltage ceramic circuit board for power electronic control modules. 5. Ceramic circuit boards for high-temperature circuits in oil wells. 6. Solid state relay ceramic circuit board. 7. DC-DC module power supply ceramic circui
With the continuous updating and upgrading of electronic products, new products have entered thousands of households. However, many friends are not very clear about the production process of PCB sampling factories when they first start planning PCBs, and do not know what line width is more suitable. Below, the editor will based on Professional PCB manufacturers are constantly updating and upgrading their electronic products, and new products have entered millions of households. However, many friends are not very clear about the production process capability of PCB manufacturers when they first plan their PCBs, and do not know what line width is suitable. Below, the editor will provide specific explanations based on the factory's production capability. 1. The width of the primary PCB power line should be above 40 mils, and the width should also be above 25 mils if conditions permit; 2. Other considerations also include practical current. Generally, 10mil can withstand a large curre
1. Board thickness: 0.8, 1.0, 1.2, 1.6, 2.0 are commonly used standards. If there are no special requirements, choose a board thickness of 1.6mm. 2. Copper foil thickness: 0.5, 1.0, 2.0 are commonly used standards. If the power is not particularly high, it is not necessary to choose a board. Manufacturers usually use a board with a power of 0.5oz. If the power is around 100W, a board with a power of 1.0 or higher will be used. 3. The colors for solder mask: green, black, red, and white are commonly used. If there are no specific requirements, green should be used. If you are using it for your own experiment, green should be used even more, as this color is the clearest for circuit boards. 4. Solder pad treatment: sinking gold, anti oxidation, tin spraying (divided into lead and lead-free), generally using the latter two can be used, and the storage time of tin spraying will be longer. 5. Screen printing colors: White and black are commonly used colors. If it is green oil, white
Generally, the thickness of copper foil (covered with copper) for single and double-sided PCB boards is about 35um (1.4mil), while another specification is 50um and 70um. The thickness of the surface layer of the multi-layer board is generally 35um=1oz (1.4mil), and the inner layer is 17.5um (0.7mil). 70% of circuit boards are used to achieve a copper foil thickness of 35um, which mainly depends on the use of the PCB and the size of the signal voltage and current; In addition, for PCBs that require excessive current, some may use 70um copper thickness, 105um copper thickness, and very rarely 140um copper thickness, etc. The thickness of copper foil is usually expressed in oz (ounces), which refers to the thickness of copper uniformly covered by 1oz of copper on an area of 1 square foot, which is approximately 1.4 mils. It is expressed in terms of weight per unit area to indicate the uniform thickness of copper foil. Use a formula to indicate that 1oz=28.35g/FT2 (FT2 is square feet
With the continuous updating and replacement of electronic products, from single panel to double-sided board, it can be said that the development is rapid. PCB is known as the "mother of electronic products", and almost all electronic products cannot do without PCB. There are also more and more new products. With the continuous updating and replacement of electronic products, from single panel to double-sided board, it can be said that the development is rapid. PCB is known as the "mother of electronic products", and almost all electronic products cannot do without PCB. There are also more and more new products, and more new products represent There is a constant demand for testing samples, but some cases are quite urgent. When making samples, we will choose urgent ones. So, what is the price of 24-hour urgent PCB sampling? Let me explain in detail below. Common Sense of 24-hour Urgent PCB Sample Prices for Direct Sales by Manufacturers In this era of money, it is the right cho
PCB sampling manufacturers generally refer to electronic products being sent to the circuit board manufacturer for processing into circuit boards for inspection after the engineer completes the PCB layout design. Due to being a newly developed product, many functions are still incomplete, and there are still many functional requirements for debugging. Only after debugging is qualified can batch production be carried out. If debugging is not qualified, it is necessary to modify, sample, and debug again, reducing many unnecessary troubles in the later stage. With the increasingly fierce market competition, price issues have become a concern for buyers. The characteristic of PCB sample prices is that they change according to the quantity and delivery time of the samples. Generally speaking, a typical single and double-sided board is not urgent, with a quantity of less than 10 pieces and a standard process within 100 * 100mm. Generally, it only costs 50 yuan. However, if your quantity i
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