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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
Everyone knows that aluminum is a kind of metal and has conductivity. How can it be used as a PCB material? This is because the aluminum substrate is composed of three layers: copper foil, insulating layer and metal aluminum. Since there is an insulating layer, can the metal layer be made of other materials besides aluminum? Such as copper plate, stainless steel, iron plate, silicon steel plate and so on. What kind of material is used for the metal substrate, in addition to considering the heat dissipation performance, but also consider the thermal expansion coefficient, thermal conductivity, strength, hardness, weight, surface condition and cost of the metal substrate. Under normal circumstances, considering the cost and technical performance, aluminum plate is an ideal choice. Available aluminum plates are 6061, 5052, 1060, etc. If there are higher thermal conductivity, mechanical properties, electrical properties and other special performance requirements, copper plates, stain
Copper foil is a kind of negative electrolytic material, a thin, continuous metal foil deposited on the base layer of the circuit board, which acts as the conductor of the PCB. It easily adheres to the insulating layer, accepts the printed protective layer, and forms a circuit pattern after corrosion. What is the role of the copper foil of the aluminum substrate? The copper foil of the aluminum substrate is also called the circuit layer of the aluminum substrate. It is the conductor of the aluminum-based circuit board and also a kind of cathode electrolytic material, which is generally deposited on the base layer of the circuit board. Thin, continuous metal foil. Copper foil has low surface oxygen characteristics and can be attached to various substrates, such as metals, insulating materials, etc., and has a wide temperature range. The copper foil of the aluminum substrate is easily adhered to the insulating layer and accepts the printed protective layer. After corrosion, the patt
The good heat dissipation performance of the aluminum substrate makes it widely used. Let the aluminum substrate manufacturers introduce the aluminum substrate in detail below. 1. Features of aluminum substrate 1. Using surface mount technology (SMT); 2. In the circuit design scheme, the heat dissipation is extremely effective treatment; 3. Reduce the operating temperature of the product, improve the power density and reliability of the product, and extend the service life of the product; 4. Reduce product volume, reduce hardware and assembly costs; 5. Replace the fragile ceramic substrate to obtain the best mechanical durability. 2, the structure of the aluminum substrate Aluminum-based copper clad laminate is a metal circuit board material, composed of copper foil, thermally conductive insulating layer and metal substrate: Copper foil: the copper clad laminate equivalent to ordinary PCB, the thickness of the circuit copper foil is loz to 10oz. Thermally conductive insul
1. Enter the PCB design system and set relevant parameters Set the environmental parameters of the design system based on personal habits, such as the size and type of grid points, the size and type of cursors, etc. Generally, the default values of the system can be used. In addition, parameters such as the size and number of layers of the circuit board need to be set. 2. Generate Import Network Table The network table is a crucial bridge and link between circuit schematic design and printed circuit board design. Network tables can be generated from circuit schematics or extracted from existing electronic circuit board files. When introducing network tables, it is necessary to check and correct errors in the circuit schematic design. 3. Arrange the packaging positions of each component The automatic layout function of the system can be utilized, but it is not very complete and requires manual adjustment of the packaging position of each component. 4. Wiring the circuit board
1. There are many factors to consider when determining the stacking structure of multi-layer PCB boards. In terms of wiring, the more layers there are, the more advantageous it is for wiring, but the cost and difficulty of making boards will also increase accordingly. For manufacturers, the symmetry of the stacked structure is the focus of attention when manufacturing PCB boards, so the selection of the number of layers needs to consider various needs to achieve the best balance. For experienced designers, after completing the pre layout of components, they will focus on analyzing the wiring bottlenecks of PCBs. Analyze the wiring density of the circuit board with other EDA tools; Determine the number and type of signal layers by synthesizing the number and types of signal lines with special wiring requirements, such as differential lines and sensitive signal lines; And then based on Determine the number of internal electrical layers based on the type of power supply, isolation, a
Previously, I worked in a small electronics factory to manually attach PCB board components, which required hundreds of pieces to be attached in a day. The efficiency was very low and could not match that of a mounting machine. Because it is a small factory, there is not enough manpower, and basically every step has been done, so I have some understanding. Firstly, the engineer uses AD software to draw the PCB. After the layout is manually completed, the drawings are handed over to the manufacturer for sampling. Generally, the PCB board and its corresponding steel mesh can be sampled within 7 working days. Then, the device is purchased according to the circuit diagram provided by the engineer. Then, it is the production line. We scrape solder paste on the screen printing table. Align the silk screen of the PCB board with the steel mesh, then fix the steel mesh, and then scrape tin on the steel mesh. Apply the solder paste onto the silk screen on the surface of the PCB board, so tha
Pcb circuit board manufacturing refers to the trial production of printed circuit boards before mass production, mainly refers to the process that electronic engineers design circuits, complete PCB, and then carry out a small amount of trial production to the factory. This is the Chinese name for PCB, which is printed circuit board, also known as printed circuit board. It is an important electronic component, the support of electronic components, and the electrical connection provider of electronic components. It is called a "printed" circuit board because it is made using electronic printing technology. Pcb circuit board manufacturing refers to the trial production of printed circuit boards before mass production, mainly refers to the process that electronic engineers design circuits, complete PCB, and then carry out a small amount of trial production to the factory. This is the manufacturing of PCB circuit boards. The production quantity of PCB samples usually does not have a spe
1. To prevent short circuits caused by tin penetrating through the component surface through the through hole during PCB wave soldering; Especially when we place the via hole on the BGA pad, we must first make a plug hole and then gild it to facilitate BGA welding. 2. After the surface mounting and component assembly of the electronic factory are completed, the PCB needs to be vacuumed on the testing machine to form negative pressure: 3. Prevent surface solder paste from flowing into the holes, causing false soldering and affecting the installation of PCB circuit boards; 4. Prevent solder beads from popping out during peak soldering, causing short circuits on the PCB circuit board; 5. Avoid flux residue in the through-hole
If a PCB circuit board is used in a humid environment, the air contains a large amount of moisture. When the moisture is too high, it will turn into water droplets and fall onto the PCB circuit board. After the water droplets scatter on the circuit board, they will attach to various pins or printed wires of electronic components. After the printed wire is soaked with water droplets, especially when the signal transmission line is relatively small and soaked for a period of time, there will be mold breakage of the printed wire, causing the circuit board to malfunction during the next operation. The causes of circuit board failures caused by moisture are classified into three categories: 1. Causing changes in circuit parameters in the PCB circuit board, leading to PCB circuit board failure; 2. Causing the circuit in the PCB circuit board to be in a short circuit state, causing the PCB circuit board to malfunction; 3. Causing open circuit in signal processing or transmission line
1、 Introduction: With the continuous improvement of human requirements for living environment, the environmental issues involved in PCB production process are particularly prominent. The topic of lead and bromine is currently the most popular; Lead-free and halogen-free technologies will affect the development of PCBs in many ways. Although at present, the changes in the surface treatment process of circuit boards are not significant and may seem distant, it should be noted that long-term slow changes will lead to significant changes. With the increasing demand for environmental protection, the surface treatment process of PCBs is bound to undergo significant changes in the future. 2、 The purpose of surface treatment is to ensure good weldability or electrical performance, which is the most basic purpose of surface treatment. Due to the tendency of copper in nature to exist in the form of oxides in the air, it is unlikely to remain the original copper for a long time, so other tr
The switch regulator used for voltage conversion uses inductance to store energy when it falls. These inductors are usually very large in size and must be positioned in the printed circuit board (PCB) planning of the switch regulator. This task is not difficult, as the current passing through the inductor may change, but it is not an instantaneous change. Changes can only be continuous and usually relatively slow. The switching regulator switches current back and forth between two different paths. This switching is very fast, and the detailed switching speed depends on the duration of the switching edge. The wiring through which switching current flows is called a thermal circuit or AC current path, which conducts current in one switching state and does not conduct current in another switching state. In PCB planning, the thermal circuit area should be small and the path should be short to minimize parasitic inductance in these wiring. Parasitic wiring inductance can generate useles
Printed circuit boards are the most active industry in the contemporary electronic component industry, and their industry growth rate is generally about 3 percentage points higher than that of the electronic component industry. It is expected to maintain rapid growth in 2006, with demand upgrading and industrial transfer being the basic driving forces for industry development, while varieties such as HDI boards, flexible boards, and IC packaging boards (BGA, CSP) will become the main growth points. In 2003, the output value of printed circuit boards in China was 50.069 billion yuan, a year-on-year increase of 333%, surpassing the second largest in the world, the United States, for the first time. In 2004 and 2005, China's PCB output value still maintained a growth rate of over 30%, estimated to reach 86.9 billion yuan in 2005, far exceeding the growth rate of the global industry. Flexible circuit boards are rapidly developing towards miniaturization in electronic devices represen
The suitability of PCB circuit boards in terms of system signal, connection distance, and capacitive load is considered before deciding whether to use transmission lines. What types of transmission lines are commonly used in PCB circuit boards? The main types of transmission lines for PCB circuit boards are: (1) Coaxial cables and twisted pair cables: They are often used for the connection between PCB circuit board transmission systems and systems. The characteristic impedance of coaxial cables is typically 50 Ω and 75 Ω, while twisted pair cables are typically 110 Ω. (2) Microstrip on PCB The Microstrip is a strip conductor (signal line). It is separated from the ground plane by a dielectric. If the thickness, width, and distance from the ground plane of a line are controllable, its characteristic impedance can also be controlled. (3) Strip lines in printed boards A strip line is a copper strip line placed between two conductive planes in the middle of a dielectric medium. I
1. Pad design (1) When designing plug-in component pads, the pad size should be designed appropriately. If the solder pad is too large, the solder spreading area is large, and the formed solder joints are not full, while the surface tension of the smaller solder pad copper foil is too small, and the formed solder joints are non wetting solder joints. The fit gap between the aperture and the component lead is too large, which is prone to false soldering. When the aperture is 0.05-0.2mm wider than the lead and the diameter of the solder pad is 2-2.5 times the aperture, it is an ideal welding condition. (2) When designing solder pads for SMD components, the following points should be considered: in order to eliminate the "shadow effect" as much as possible, the solder end or pin of SMD should be facing the direction of the tin flow to facilitate contact with the tin flow and reduce false soldering and solder leakage. For smaller components, they should not be placed behind larger co
Sometimes, PCB circuit board substrates can cause open circuits, which are mainly caused by: 1. There are scratches on the copper clad plate before entering the warehouse; 2. The copper clad plate was scratched during the cutting process; 3. The copper clad plate was scratched by the drilling nozzle during drilling; 4. The copper clad plate was scratched during transportation; 5. The surface copper foil was damaged due to improper operation during the stacking of boards after copper deposition; 6. The copper foil on the surface of the production board was scratched when passing through the leveling machine. Improvement methods: 1. Before entering the warehouse, the IQC must conduct spot checks on the copper clad PCB circuit board substrate to check if there are scratches or exposed substrate on the board surface. If there are any, the supplier should be contacted in a timely manner to make appropriate treatment based on the actual situation. 2. The PCB circuit board substr
After decades of development, the PCB circuit board industry has become extremely mature in terms of technology. Key technologies such as drilling, copper deposition, exposure, development, and etching have been well controlled by automation equipment, making PCB circuit board factories an equipment and fixed asset intensive industry. Business owners have to come up with low price strategies in the fierce market competition. Therefore, the market will be full of the phenomenon of Gresham's law. How to stand out from fierce market competition? It is worth every manager's deep thinking.The rise of any industry is first about creativity, then about the market, and finally about quality. At the beginning, insightful individuals will first identify potential market opportunities, enter the market first, and quickly gain profits. Then more and more people will discover such business opportunities and enter the market competition. Finally, when the industry is saturated, end customers can fre
The competition of enterprises is diversified, from the previous short Plate theory theory to the current long Plate theory theory. Faced with fierce market competition, limited resources of enterprises can only be concentrated on a certain board, making it bigger and stronger. This has led many electronic product companies to only focus on research and development and sales, outsourcing PCBA electronic manufacturing to professional companies, and no longer trying out material procurement, outsourcing processing, supply chain management, and so on that they are not good at. The benefit of doing so is to reduce manpower investment and management costs, as well as the risk losses caused by one's lack of expertise. Careful people will find that in recent years, more and more companies have begun to seek professional PCBA electronic manufacturing resources.Another driving factor is the country's advocacy for mass entrepreneurship and innovation, which has led to an increasing number of sma
(1) Although the wiring spacing and wiring width are consistent, the spacing of Coupon Test point is fixed at 2.54mm (to meet the spacing of test probes), and the spacing of the end of the actual wiring in the board (i.e., the golden finger) is variable. With the emergence of QFP, PLCC, and BGA packages, the pin spacing of some chips is far less than 2.54mm (i.e., the spacing of Coupon Test point).(2) Coupon wiring is an ideal straight line, while the actual wiring on the board is often designed and produced according to actual needs. PCB designers and production personnel can easily idealize Coupon's wiring, but the actual wiring on the PCB board may undergo irregular changes due to practical needs.(3) The positions of Coupon and the actual wiring inside the board are different on the entire PCB board. Coupons are located in the middle or edge of the PCB board and are often removed by the manufacturer when the PCB board leaves the factory. The actual positions of the wiring inside the
(1) The distance between the Test point of Coupon is different from that of the cabling of Coupon, which will cause impedance discontinuity between the Test point and the cabling. This will result in different impedance test results.(2) The impedance changes reflected by curved wiring and ideal wiring are inconsistent. The characteristic impedance at the bending and turning point of the wiring is often discontinuous, while Coupon's idealized wiring cannot reflect the impedance discontinuity caused by the bending of the wiring.(3) Coupon and real wiring have different positions on the PCB board. Currently, PCB boards are designed with multi-layer wiring and require pressing during production. When a PCB board is pressed, the pressure on different positions of the board cannot be consistent, and the thickness of the dielectric layer at different positions will also vary. As a result, the dielectric constant of the PCB board made from this method often varies at different positions, and t
(1) Visual inspection PCB boards generally undergo electrical testing before leaving the factory. We inspect the appearance of PCB boards through visual inspection methods upon receipt, including warping, scratches, flying wires, broken wires, ink blockage, unclear screen printing, solder pad oxidation, uneven solder pads, blocked vias, and burrs on the board edges (2) Dimensional measurement Use a micrometer to measure the thickness, shape, dimensions, and V-CUT of the PCB board to ensure compliance with the Gerber file design. (3) Furnace temperature test Many PCB boards, due to poor process control, experience yellowing and warping when subjected to high temperatures such as reflow soldering. When outsourcing processing, it is essential to require the PCB board to undergo furnace temperature testing first to avoid mass welding defects or affecting the future reliability and durability of the product. Especially for PCB boards with high TG design, this inspection is particular
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