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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
One, circuit board factory tin surface quality defects So what are the factors that cause the bad tin surface of the tin surface? According to the analysis of the editor, there are the following points 1. The operation is not in accordance with the operating specifications when shipping The circuit industry has extremely strict requirements on the workshop environment and the standard operation of employees, especially the chemical reaction environment is required in the circuit board production process, so the infiltration of impurities is not allowed. After the board spraying process is completed, the subsequent one All series require employees to wear anti-static gloves to operate, because finger sweat or stains directly contact the surface, which will cause surface oxidation. If it causes defects, it is extremely difficult to find, and it is irregular, and it is difficult to be exposed in testing and tinning experiments. 2. The tin furnace for spraying tin is not cleaned on
The transmission rate of high-speed PCB design wiring systems is constantly accelerating with the passage of time, but this also brings a new challenge - the anti-interference ability is becoming weaker and weaker. All of this stems from the fact that the higher the frequency of information transmission, the more sensitive the signal, and the weaker the energy, making the wiring system increasingly susceptible to interference. In some common electronic devices, such as computer screens, mobile phones, motors, radio broadcasting equipment, etc., cables and devices can interfere with other components or be severely interfered by other interference sources. Today, let me introduce a shielding method in high-frequency PCB design to you, let's take a look together! Especially when using high-speed data networks, the time required to intercept a large amount of information is significantly lower than the time required to intercept low-speed data transmission. The twisted pair in data twis
High frequency PCB circuit board is a special type of circuit board with high electromagnetic frequency. Generally speaking, high frequency can be defined as a frequency above 1GHz. Its various physical properties, accuracy, and technical parameters require very high requirements, and are commonly used in fields such as automotive collision prevention systems, satellite systems, and radio systems. Wireless infrastructure needs to provide sufficiently low insertion loss in order to effectively improve energy utilization efficiency. With the arrival of 4G services, RF products need to provide wider bandwidth and be compatible with 3G and 2G services. PCB sample manufacturers believe that at the same time, base stations are becoming smaller and lighter, and are installed on top of towers, which is also promoting the development of miniaturization of circuit boards. Many manufacturers are seeking materials that can miniaturize antennas in handheld devices such as tablets. Optimistic
Q: How to conduct pilot testing on PCB circuit boards? Answer: Today, electronic products are becoming thinner and shorter, and the preset wiring of PCBs is becoming more complex and difficult. In addition to balancing functionality and safety, it is also necessary to be producible and testable. We hereby provide a rule for the reference of the preset wiring engineer regarding the need for measurability. Kunshan circuit board sampling manufacturers believe that if they pay attention to it, it will save your company considerable tooling production costs and promote the reliability of testing and the service life of fixtures. Although there is a double-sided fixture, it is preferable to place the measured point on a unified surface. The important consideration is to be able to perform single-sided testing. If there is difficulty, the TOP SIZE needle points should be less than the BOTTON SIZE. 2. Priority of measurement points: I Test pad II Component lead III Via hole -->but not
Key components require preset test points on the PCB circuit board. The solder pads used for welding appearance assembly components are not allowed to be used as inspection points. A dedicated test solder pad must be pre-set to ensure smooth solder joint inspection and production debugging. The solder pads used for testing should be arranged on the unified side of the PCB circuit board as much as possible, which is beneficial for testing and reduces the cost of testing. The following circuit board sample manufacturer will tell you its process preset requirements: (1) The distance between test points and the edge of the PCB circuit board should be greater than 5mm; (2) The test point should not be covered by solder mask or text ink; (3) The testing point should be preferably coated with solder or selected with a soft, easy to penetrate, and non oxidizing metal to ensure reliable grounding and extend the service life of the probe (4) The testing point should be placed 1mm away fr
PCBA test stand is a device used to test PCBA finished products. When making PCBA test racks, PCBA processing plants usually need to provide Gerber files and PCBA samples to facilitate the production of test racks. For the current PCBA test bench, only a few pressure plate buckles are installed on the test bench, and the PCBA is fixed by a thimble and pressure plate buckle. During the PCBA function test, press the PCBA into the pressure plate buckle with both hands. Due to uneven force or insufficient compression, PCBA can easily cause poor contact between the testing needle and PCBA, seriously affecting testing efficiency and accuracy; If too much force is applied, it is easy to deform or damage the PCBA when pressing down, and it is also easy to damage the test needle of the testing frame, causing significant losses. 1、 Material preparation After determining the plan based on the information, it is necessary to prepare hardware materials (electronic components), relevant additi
Aluminum substrate is a unique metal based copper clad plate with good thermal conductivity, electrical insulation performance, and mechanical processing performance. Let the aluminum substrate manufacturer provide you with a detailed explanation of the aluminum substrate. 1、 Characteristics of aluminum substrate 1. Adopting Surface Mount Technology (SMT); 2. Effectively handle thermal diffusion in circuit design schemes; 3. Reduce product operating temperature, improve product power density and reliability, and extend product service life; 4. Reduce product volume, reduce hardware and assembly costs; 5. Replace fragile ceramic substrates for better mechanical durability. 2、 Structure of aluminum substrate Aluminum based copper clad plate is a metal circuit board material composed of copper foil, thermal insulation layer, and metal substrate: Copper foil: equivalent to a copper clad board of a regular PCB, with a copper foil thickness of loz to 10oz for the circuit. Therm
1. If the PCB has a large amount of ground, such as SGND, AGND, GND, etc., it is necessary to use the most important "ground" as the reference for independent copper coating based on the different positions of the PCB surface. Separate the digital and analog power lines for copper coating, and before copper coating, thicken the corresponding power lines: 5.0V, 3.3V, etc. 2. For single point connections to different locations, the method is to connect through a 0 ohm resistor, magnetic bead, or inductor. 3. The crystal oscillator in the circuit is a high-frequency emission source. For the copper coating near the crystal oscillator, the method is to surround the crystal oscillator with copper coating, and then ground the outer shell of the crystal oscillator separately. 4. If the problem of islands (dead zones) is significant, then define a place and add it through a hole. 5. When starting wiring, the ground wire should be treated equally. When wiring, the ground wire should be pro
During the production process of PCB circuit boards, it is common to encounter poor copper wire detachment, also known as copper throwing, which affects product quality. So, what are the common reasons for PCB circuit board copper throwing? 1、 PCB process factors: 1. Copper foil is excessively etched, and the electrolytic copper foil used in the market is generally single-sided galvanized (commonly known as ashed foil) and single-sided copper plating (commonly known as reddened foil). The common copper throwing is generally ashed foil above 70um, while reddened foil and ashed foil below 18um have not undergone bulk copper throwing. 2. Local collisions occurred during the PCB process, causing the copper wire to detach from the substrate due to external mechanical forces. This defect manifests as poor positioning or directionality, where the detached copper wire will have obvious twisting or scratches/impact marks in the same direction. 3. Unreasonable PCB circuit design, using t
The so-called copper coating of PCB circuit boards refers to using the idle space on the PCB as a reference plane, and then filling it with solid copper. These copper areas are also known as copper filling. The significance of copper coating is to reduce the impedance of the ground wire and improve its anti-interference ability; Reduce voltage drop and improve power efficiency; Connecting to the ground wire can also reduce the loop area. There are generally two methods of copper coating, namely large-scale copper coating and grid copper coating. Large area copper coating has the dual functions of increasing current and shielding, but if the copper coating is applied on a large area, the board may curl up and even bubble during wave soldering. Therefore, when covering a large area with copper, several grooves are usually opened to alleviate blistering on the copper foil. Grid copper coating, from the perspective of heat dissipation, reduces the heating surface of copper and plays a
Electrical principles and mechanical structure design, determining the size and structural shape of the PCB based on the overall structure of the machine. Draw a process diagram of the SMT printed circuit board, indicating the length, width, and thickness of the PCB, the position and size of structural components and assembly holes, and leaving edge dimensions, so that circuit designers can carry out wiring design within an effective range. The choice of assembly form depends on the type of components in the circuit, the size of the circuit board, and the equipment conditions of the production line. PCB board sampling shares with you the principles for selecting the assembly form of printed boards: following the principles of optimizing processes, reducing costs, and improving product quality, first determine the overall goals of electronic product functions, performance indicators, costs, and overall dimensions of the entire machine. When developing and designing new products, th
Pre impregnated material is a sheet-like material composed of resin and carrier. Among them, the resin is in the B-stage, under the action of temperature and pressure, it has fluidity and can quickly cure and complete the bonding process, and together with the carrier, forms an insulation layer. Commonly known as semi cured sheet or adhesive sheet. To ensure the high reliability and quality stability of multi-layer printed circuit boards, it is necessary to conduct quality testing on the characteristics of semi-solid chips (test layer pressing method). The characteristics of electroplating semi cured chips on circuit boards include two parts: pre lamination characteristics and post lamination characteristics. The characteristics before lamination mainly refer to: resin content%, fluidity%, volatile content% and gel time (S). The circuit board prototype manufacturer will share with you the characteristics after lamination, including electrical performance, thermal shock performance,
1. Process half of the hole with a double V-shaped cutting tool. 2. Second drill adds support holes at the edge of the hole, removes copper skin in advance, reduces burrs, and uses slot cutters to produce the drill, optimizing the speed and falling speed. 3. Copper plating is applied to the substrate by depositing a layer of copper on the hole wall of the circular holes on the edge of the board. 4. After laminating, exposing, and developing the outer circuit, the substrate is subjected to secondary copper plating and tin plating to thicken the copper layer on the hole wall of the circular hole at the edge of the board and cover it with a tin layer with anti-corrosion properties; 5. Half hole forming involves cutting the circular holes on the edge of the board in half to form a half hole; 6. Remove the anti electroplating film pressed during the process of film removal and pressing; 7. Etching is performed on the substrate to remove the exposed copper on the outer layer of the
a) Ma Keng: Ma Keng is the result of organic pollution. A large pit usually indicates oil pollution. If the stirring is poor, the bubbles cannot be expelled, which will form pits. Wetting agents can be used to reduce its impact. We usually refer to small pitting as pinholes. Poor pre-treatment, metallic impurities, low boric acid content, and low plating temperature can all cause pinholes. Maintenance and process control of the plating solution are crucial, and anti pinhole agents should be used as process stabilizers to supplement. b) Roughness and burrs: Roughness indicates that the solution is dirty, which can be corrected by sufficient filtration (high pH can easily form hydroxide precipitates and should be controlled). If the current density is too high, impurities are brought in by impure anode mud and added water, and in severe cases, roughness and burrs will be produced. c) Low adhesion: If the copper coating is not fully oxidized, the coating will peel off and the adhesi
1、 Dry film mask with perforation Many customers believe that after a hole is broken, the film temperature and pressure should be increased to enhance its adhesion. However, this view is not correct because the solvent in the corrosion resistant layer evaporates excessively when the temperature and pressure are too high, making the dry film brittle and thin, making it easy to break through during development. We always need to maintain the toughness of the dry film. Therefore, after a hole is broken, we can improve it from the following points: 1. Reduce film temperature and pressure 2. Improve drilling edge 3. Increase exposure energy 4. Reduce development pressure 5. After applying the film, the parking time should not be too long to avoid causing the semi fluid like drug film at the corner to diffuse and thin under pressure 6. During the film application process, do not tension the dry film too tightly 2、 Penetration occurs during dry film electroplating The reason for
In terms of electrical performance, it includes dielectric constant and loss angle, ① dielectric constant or dielectric coefficient, and the surface is a coefficient of insulation capacity characteristics, measured in units of ε In actual production, the dielectric constant is not an absolute value, but expressed in the form of relative dielectric constant The loss angle, also known as the "loss factor" or "damping factor", is the tangent of the phase difference angle between the strain and stress cycles of a material in the residual alternating field, which is also equal to the ratio of the loss film amount of the material to the stored energy modulus. Thermal performance method: It is necessary to have a certain understanding of the relevant characteristic parameters. Below, we will introduce the definition manual of thermal performance parameters for two different sheet materials: ① From the perspective of board types alone, it can be mainly divided into Tg value, Td value, CT
① Inner layer production: Multilayer circuit boards are made by pressing two or more double-sided boards. For some high-frequency multi-layer boards, the inner layer holes may be blind holes, and the inner layer boards need to be drilled and then pressed together. ② Drilling: Based on the production capacity of the factory, verify the data. If the line width moment or aperture is less than the manufacturing capacity, the engineering department should improve communication with the customer and reach a consensus to compensate for a certain stroke of the line width moment or aperture. Generally, the drilling roughness is controlled at ≤ 25.4um. ③ Copper plating: Usually, during transportation or production, there may be scratches on the substrate copper foil, causing it to be exposed to the surface. It is necessary to go through processes such as copper plating to ensure that the thickness of the PCB board copper foil meets the customer's order requirements. Secondly, according to
1. IPC/EIA/JEDECJ-STD-003A: Solderability testing for customized circuit boards. 2. IPC-6018A: Manufacturing inspection and testing of microwave finished circuit boards, including manufacturing performance and qualification requirements for high-frequency circuit boards. 3. IPC-M-103: Surface Mount Assembly Manual Standard, which includes all 21 IPC documents related to PCB surface mount. 4. IPC-M-I04: PCB Manufacturing and Assembly Manual Standard, which includes the 10 most widely used documents related to circuit board manufacturing and assembly. 5. IPC-DRM-53: Introduction to Electronic PCB Assembly Desktop Reference Manual, with illustrations and photos describing through-hole installation and surface mount assembly techniques. 6. IPC-Ca-821: General requirements for thermal conductive adhesives, including requirements and testing methods for thermal conductive dielectrics that bond components to appropriate positions. 7. IPC-3406: Guidelines for Conductive Surface Coati
During the production process of PCB circuit boards, it is common to encounter poor copper wire detachment, also known as copper throwing, which affects product quality. So, what are the common reasons for PCB circuit board copper throwing? 1、 PCB process factors: 1. Copper foil is excessively etched, and the electrolytic copper foil used in the market is generally single-sided galvanized (commonly known as ashed foil) and single-sided copper plating (commonly known as reddened foil). The common copper throwing is generally ashed foil above 70um, while reddened foil and ashed foil below 18um have not undergone bulk copper throwing. 2. Local collisions occurred during the PCB process, causing the copper wire to detach from the substrate due to external mechanical forces. This defect manifests as poor positioning or directionality, where the detached copper wire will have obvious twisting or scratches/impact marks in the same direction. 3. Unreasonable PCB circuit design, using t
Aluminum substrate is a unique metal based copper clad plate with good thermal conductivity, electrical insulation performance, and mechanical processing performance. Let the aluminum substrate manufacturer provide you with a detailed explanation of the aluminum substrate. 1、 Characteristics of aluminum substrate 1. Adopting Surface Mount Technology (SMT); 2. Effectively handle thermal diffusion in circuit design schemes; 3. Reduce product operating temperature, improve product power density and reliability, and extend product service life; 4. Reduce product volume, reduce hardware and assembly costs; 5. Replace fragile ceramic substrates for better mechanical durability. 2、 Structure of aluminum substrate Aluminum based copper clad plate is a metal circuit board material composed of copper foil, thermal insulation layer, and metal substrate: Copper foil: equivalent to a copper clad board of a regular PCB, with a copper foil thickness of loz to 10oz for the circuit. Therm
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