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Many customers are looking for PCB circuit board manufacturers and don't know how to choose. They accidentally choose small processing factories or workshops. As discussed earlier, they can switch orders to other strong manufacturers for sample production in the next second, which leads to a lot of wasted opportunities. When looking for a printed circuit board manufacturer, it is important to conduct a survey at the factory in order to effectively assess the manufacturer's strength. How to identify the strength of PCB circuit board manufacturers? Today, Weifu Circuit Board will teach you how to identify manufacturers with strong capabilities, prevent such incidents from happening, and save your time and costs? Before choosing a PCB circuit board manufacturer, you need to understand their company's situation, such as whether the processing technology is mature, whether the company's scale system is comprehensive, whether the company's equipment is second-hand, whether it has UL certification, and the company's cultural and service system. These are all things that we must first understand. After understanding all of these, you can choose to go to the factory for survey. This can be said to be very stable, which can save you time and costs, and also avoid the possibility of choosing some small factories. Yes, this is what you said you need to know before choosing a double sided PCB manufacturer. Don't just think that the price is cheap and nothing is important. The hidden dangers that this will bring to you are unpredictable. Our Weifu circuit board has been recognized by so many manufacturers because all of our above conditions are qualified, so customers can rest assured to cooperate with us. If you have any needs, you can call us for consultation, and we are dedicated to developing a reasonable PCB circuit board solution for you. By reading the above content, I believe everyone has an understanding of how to identify the strength of PCB circuit board manufacturers. Weifu Circuit Board has shared this with you. If you want to learn more related information, you can consult our customer service personnel online or search on the website of Dongguan Weifu Electric Road Technology Co., Ltd. We will be happy to provide you with reasonable solutions.

Today we bring you a complete version of the production process for circuit boards, hoping to give you a deeper understanding of circuit board production! Cutting materials Purpose: According to the requirements of the engineering data MI, cut into small pieces of production boards on large sheets that meet the requirements. Small pieces of boards that meet customer requirements Process: Large plate material → Cutting according to MI requirements → Curing plate → Rounding corner/grinding edge → Plate discharge Drilling Purpose: Based on engineering data, drill the required hole diameter at the corresponding position on the sheet metal that meets the required dimensions Process: Stacked board pins → Upper board → Drilling → Lower board → Inspection/repair Sinking copper Purpose: Copper deposition is the use of chemical methods to deposit a thin layer of copper on the wall of insulating holes Process: Rough grinding → Hanging plate → Automatic copper sinking line → Bottom plate → Immersion of% dilute H2SO4 → Thickening copper Graph transfer Purpose: Image transfer refers to the transfer of images from the production film to the board Process: (Blue oil process): Grinding the plate → Printing the first side → Drying → Printing the second side → Drying → Blowing out → Film development → Inspection; (Dry film process): hemp board → pressing → standing → alignment → exposure → standing → developing → inspection Graphic electroplating Purpose: Graphic electroplating is the electroplating of a copper layer with the required thickness and a gold nickel or tin layer with the required thickness on the exposed copper skin or hole wall of the circuit pattern Process: Upper plate → Oil removal → Secondary water washing → Micro corrosion → Water washing → Acid washing → Copper plating → Water washing → Acid immersion → Tin plating → Water washing → Lower plate Debonding Purpose: To remove the anti electroplating coating layer with NaOH solution and expose the non circuit copper layer Process: Water film: Insert frame → Soak in alkali → Rinse → Scrub → Passing machine; Dry film: release board → pass machine Etching Purpose: Etching is the use of chemical reaction methods to corrode the copper layer on non circuit parts Green oil Purpose: Green oil is to transfer the graphics of the green oil film onto the board, playing a role in protecting the circuit and preventing tin on the circuit when welding parts Process: Grinding plate → Printing photosensitive green oil → Curing plate → Exposure → Development; Grinding board → Printing the first side → Drying board → Printing the second side → Drying board Characters Purpose: Characters are provided as easily recognizable markers Process: After green oil is finally cured, cool and stand still, adjust the screen, print characters, and finally cure Gold-plated fingers Purpose: To coat the plug finger with a nickel/gold layer of required thickness, making it more durable and wear-resistant Process: Board loading → Oil removal → Water washing twice → Micro etching → Water washing twice → Acid washing → Copper plating → Water washing → Nickel plating → Water washing → Gold plating Tin plate (a parallel process) Purpose: Tin spraying is to spray a layer of lead tin on the exposed copper surface that is not covered with solder mask to protect the copper surface from corrosion and oxidation, ensuring good welding performance Process: Micro etching → Air drying → Preheating → Rosin coating → Solder coating → Hot air leveling → Air cooling → Washing and air drying Forming Purpose: To create the desired shape for customers through mold stamping or CNC gongs, including organic gongs, beer boards, hand gongs, and hand cutting Explanation: The accuracy of the data gong machine board and the beer board is relatively high, followed by the hand gong. The lowest tool for hand cutting boards can only make some simple shapes Testing Purpose: Through electronic 100% testing, detect defects that affect functionality such as open circuits and short circuits that are difficult to detect visually Process: Upper mold → Board placement → Testing → Qualified → FQC visual inspection → Unqualified → Repair → Retest → OK → REJ → Scrap Final inspection Purpose: Through 100% visual inspection of the appearance defects of the board, and repairing minor defects, to avoid problems and defective boards from flowing out Specific workflow: incoming materials → viewing materials → visual inspection → qualified → FQA spot check → qualified → packaging → unqualified → handling → inspection OK

Assuming that the frequency of a digital logic circuit reaches or exceeds 45MHz~50MHz, and the circuit operating above this frequency occupies a certain proportion of the entire electronic system (such as 1/3), it is usually called a high-frequency circuit (multi-layer circuit board). High frequency circuit board planning is a very chaotic planning process, and its wiring is crucial to the entire planning! First move, wiring of high and multi-layer circuit boards High frequency circuits often have high integration and high wiring density. Choosing multi-layer circuit boards is not only necessary for wiring, but also a useful means to reduce interference. In the PCBLayout stage, selecting a certain number of layers of printed circuit board scale reasonably can make full use of intermediate layers to set shielding, better achieve nearby grounding, effectively reduce parasitic inductance and shorten signal transmission length, and also significantly reduce signal interference. All of these methods are beneficial for the reliability of high-frequency circuits. There are materials showing that when using the same material, the noise of a four layer board (multi-layer circuit board) is 20dB lower than that of a double-sided board. However, there is also a problem together. The higher the number of half layers of a circuit board, the more chaotic the manufacturing process, and the higher the unit cost. This requires us to not only choose the appropriate number of layers of circuit boards when terminating PCBLayout, but also to stop reasonable equipment planning and choose the correct wiring rules to complete the planning. The second trick is to minimize the bending of the leads between the pins of high-speed electronic equipment, as much as possible It is best to choose a straight lead for high-frequency circuit wiring, which needs to be colored. A 45 degree broken line or circular arc can be used for coloring. This requirement is only used for the fixation strength of the copper foil in low-frequency circuits, but in high-frequency circuits, meeting this requirement can reduce the external emission and mutual coupling of high-frequency signals. The third trick is to replace the lead wires between the pins of high-frequency circuit equipment as little as possible The so-called "less interlayer replacement of leads is better" refers to the use of fewer vias (Via) in the process of component connection. According to the side, a PCB through-hole can bring about a scattered capacitance of about 0.5pF, reducing the number of through-holes can significantly increase speed and reduce the possibility of data errors.

What inspections are needed during the production process of printed circuit board to reassure customers? Many customers worry about quality issues when selecting suppliers. Today, the editor of Weifu PCB circuit board will share with you how we inspect circuit board at every stage of the entire production process? Interested friends, don't miss out! Firstly, incoming inspection: acceptance inspection of raw materials, auxiliary materials, outsourced parts, and purchased parts before entering the factory for storage. Ensure that unqualified materials are not stored or used. Secondly, there is process inspection: also known as process inspection, which inspects the work in progress during the production process at the production site. Not only does it prevent unqualified products from flowing into the next process, but it also avoids the abnormal occurrence of large quantities of unqualified products in the production process. Final inspection: also known as product inspection, the inspection of completed products before storage and delivery. This inspection is conducted in full accordance with the customer's contract and relevant regulatory requirements to ensure customer acceptance. That's all for the introduction of the entire quality inspection of the circuit board/circuit board factory above. The control system of the double sided Pcb factory also follows this process.

At present, there are two ways for us to electroplate PCB circuit board: full plate arc plating and graphic plating. Graphic electroplating is a process in which a printed circuit board undergoes graphic transfer to protect the copper part of the conductor that does not require copper plating with a dry film. The wires and connecting plates that require copper plating are then selectively electroplated with copper, followed by electroplating with Sn (or Sn/Pb) corrosion inhibitors. After electroplating, the PCBA Circuit Board can be coated, etched, and the anti-corrosion agent removed to obtain the outer circuit. The overall process of electroplating technology 1. Pickling → Copper plating on the entire board → Pattern transfer → Acid degreasing → Secondary countercurrent rinsing → Micro etching → Secondary → Pickling → Tin plating → Secondary countercurrent rinsing 2. Countercurrent rinsing → pickling → graphic copper plating → secondary countercurrent rinsing → nickel plating → secondary water washing → citric acid immersion → gold plating → recycling → 2-3 levels of pure water washing → drying Important steps in graphic electroplating Inspection: The circuit board factory (Shenzhen circuit board) mainly checks whether there is excess dry film, whether the lines are complete, and whether there are dry film residues in the holes during inspection. Oil removal: During the image transfer process, after film application, exposure, development, inspection, and other operations, there may be fingerprints, dust, oil stains, and residual film on the board. If not handled properly, it can cause weak bonding between the copper coating and the substrate copper. During the operation, we suggest that the operator wear gloves with their full name. Similarly, printed circuit boards are made of dry film and bare copper. To remove oil, it is necessary to remove oil stains from the copper surface without damaging the organic dry film. Therefore, acidic oil removal is chosen. The main components of the degreasing solution are sulfuric acid and phosphoric acid. Our circuit board manufacturers are particularly careful and cautious during wake-up operations, as they involve chemical substances. Micro etching: Remove the copper oxide layer in the circuit and hole, increase surface roughness, and thus improve the bonding between the coating and the substrate copper. There are two commonly used types of micro etching solutions: persulfate type and sulfuric acid hydrogen peroxide type, with sodium persulfate and ammonium persulfate as the main types. Ammonium persulfate micro etching solution is prone to decomposition, and the decomposed ammonia gas affects the environment and is not conducive to environmental protection. At the same time, the micro etching rate is also unstable. Sodium persulfate micro etching solution is stable, easy to control, and has a longer service life. The sulfuric acid hydrogen peroxide system is unstable, prone to decomposition and volatilization, and has a large fluctuation in micro etching rate. However, its wastewater is easy to treat, which is beneficial for environmental protection. Acid leaching: Circuit board factories (Shenzhen circuit boards) generally conduct copper plating or tin plating in acidic environments. In order to prevent water from entering, acid leaching treatment is required before electroplating.

With the development of the electrical era, there are more and more electromagnetic wave sources in human living environments, such as radio broadcasting, television, microwave communication, household appliances, power frequency electromagnetic fields of transmission lines, high-frequency electromagnetic fields, etc. When the field strength of these electromagnetic fields exceeds a certain limit and the action time is long enough, it may endanger human health; It will also interfere with other electronic devices and communication. Protection is required for this. In the development, production, and use of electronic products, concepts such as electromagnetic interference and shielding are often proposed. The core of electronic products during normal operation is a coordinated working process between the PCB board and the components, components, etc. installed on it. It is very important to improve the performance indicators of electronic products and reduce the impact of electromagnetic interference. 1. PCB board design Printed Circuit Board (PCB) is the support component for circuit components and devices in electronic products. It provides electrical connections between circuit components and devices, and is the most basic component of various electronic devices. The performance of PCB board directly affects the quality and performance of electronic devices. With the development of integrated circuits, SMT technology, and micro assembly technology, there are more and more high-density and multifunctional electronic products, resulting in complex wire layout, numerous parts and components, and dense installation on multi layer PCB, which inevitably leads to increasingly serious interference between them. Therefore, suppressing electromagnetic interference has become the key to whether an electronic system can work normally. Similarly, with the development of electrical technology, the density of PCBs is increasing, and the quality of PCB board design has a significant impact on the interference and anti-interference ability of circuits. To achieve optimal performance in electronic circuits, in addition to component selection and circuit design, a good PCB board design is also a very important factor in electromagnetic compatibility (EMC). 1.1 Reasonable PCB board layer design Based on the complexity of the circuit, selecting the appropriate number of PCB layers can effectively reduce electromagnetic interference, significantly reduce the volume of the PCB, the length of current circuits and branch lines, and significantly reduce cross interference between signals. Experiments have shown that for the same material, the noise of a four layer board is 20dB lower than that of a double-layer board. However, the higher the number of layers, the more complex the manufacturing process and the higher the manufacturing cost. In multi-layer PCB board wiring, it is best to use a "well" shaped mesh wiring structure between adjacent layers, that is, the directions of the adjacent layers are perpendicular to each other. For example, the upper side of a PCB board is horizontally wired, the lower side is vertically wired, and connected through holes. 1.2 Reasonable PCB board size design When the PCB board size is too large, it will lead to the growth of printed wires, an increase in impedance, a decrease in noise resistance, and a corresponding increase in equipment volume and cost. If the size is too small, the heat dissipation is poor and adjacent lines are easily disturbed. Overall, in the mechanical layer, the physical border, i.e. the overall dimensions of the PCB board, is determined, while the keepout layer determines the effective area for layout and routing. Generally, based on the number of functional units in a circuit, all components of the circuit are assembled and the optimal shape and size of the PCB circuit board are determined. Usually, rectangles are chosen with a aspect ratio of 3:2. When the size of the circuit board surface is greater than 150mm * 200mm, the mechanical strength of the PCB board should be considered. 2. Layout of PCB board In PCB board design, electronic engineers may only focus on increasing density, reducing space occupation, making it simple, or pursuing aesthetics and uniform layout, ignoring the impact of circuit layout on electromagnetic compatibility (EMC), causing a large amount of signal radiation to interfere with each other in space. A poor PCB wiring can lead to more electromagnetic compatibility (EMC) issues rather than eliminating them. The component layout and wiring of digital circuits, analog circuits, and power circuits in electronic devices have different characteristics, and the interference they generate and the methods of suppressing interference are different. Due to different frequencies, high-frequency and low-frequency circuits have different interference and suppression methods. So when laying out components, digital circuits, analog circuits, and power circuits should be placed separately, and high-frequency circuits should be separated from low-frequency circuits. If conditions permit, they should be isolated or made into a separate PCB board. Special attention should also be paid to the distribution of strong and weak signal components and the direction and path of signal transmission in the layout. 2.1 Component layout of PCB board The layout of PCB components is similar to other logic circuits, and related components should be placed as close as possible to achieve better noise resistance. The placement of components on the PCB board should fully consider the issue of electromagnetic interference resistance. One principle is to minimize the lead wires between components. In terms of layout, the analog signal section, high-speed digital circuit section, and noise source section (such as relays, high current switches, etc.) should be reasonably separated to minimize signal coupling between them. The clock inputs of clock generators, crystal oscillators, and CPUs are prone to noise and should be placed closer to each other. Devices, low current circuits, high current circuits, etc. that are prone to generating noise should be kept as far away from logic circuits as possible. If possible, it is very important to make a separate PCB board. General layout requirements for PCB components: The layout of circuit components and signal paths must minimize the mutual coupling of useless signals. 1) Low level signal channels cannot be close to high-level signal channels and unfiltered power lines, including circuits that can generate transient processes. 2) Separate low-level analog circuits from digital circuits to avoid common impedance coupling between analog circuits, digital circuits, and power supply common circuits. 3) High, medium, and low-speed logic circuits require different areas on the PCB board. 4) When arranging the circuit, the length of the signal line should be minimized. 5) Ensure that there are no excessively long parallel signal lines between adjacent boards, between adjacent layers of the same board, or between adjacent wiring on the same layer. 6) Electromagnetic interference (EMI) filters should be placed as close as possible to the electromagnetic interference source and on the same circuit board. 7) DC/DC converters, switching elements, and rectifiers should be placed as close as possible to the transformer to minimize their wire length. 8) Place voltage regulating elements and filtering capacitors as close as possible to the rectifier diode. 9) PCB boards are divided according to frequency and current switching characteristics, and the distance between noisy and non noisy components should be further away. 10) Noise sensitive wiring should not be parallel to high current or high-speed switching lines. 11) Special attention should be paid to heat dissipation in component layout. For high-power circuits, heating elements such as power tubes and transformers should be placed as far apart as possible to facilitate heat dissipation. They should not be concentrated in one place, and high capacitance should not be too close to prevent premature aging of the electrolyte. 2.2 PCB board wiring The composition of a PCB board is a multi-layer structure that uses a series of laminations, wiring, and pre impregnation treatments on vertical layers. In multi-layer PCB boards, for the convenience of debugging, signal lines are arranged on the outermost layer. In high-frequency situations, the wiring, vias, resistors, capacitors, and distributed inductance and capacitance of connectors on the PCB board cannot be ignored. Resistance generates reflection and absorption of high-frequency signals. The distributed capacitance of the wiring also plays a role. When the length of the wiring is greater than 1/20 of the corresponding wavelength of the noise frequency, an antenna effect is generated, and noise is emitted outward through the wiring. The wire connections on PCB boards are mostly completed through through-holes. A through-hole can bring about a distributed capacitance of about 0.5pF, and reducing the number of through-holes can significantly improve speed. The packaging material of an integrated circuit itself introduces a 2-6 pF capacitor. A connector on a PCB board with a distributed inductance of 520nH. A 24 pin integrated circuit socket with dual inline insertion, introducing a distributed inductance of 4-18nH. General requirements to be followed to avoid the influence of PCB board wiring distribution parameters: 1) Increase the spacing of the wiring to reduce crosstalk caused by capacitive coupling. 2) When wiring with dual panels, the wires on both sides should be perpendicular, diagonally crossed, or bent to avoid being parallel and reduce parasitic coupling; Printed wires used as inputs and outputs for circuits should be avoided as much as possible from being adjacent and parallel to avoid feedback. It is best to add a grounding wire between these wires. 3) Lay sensitive high-frequency lines away from high noise power lines to reduce mutual coupling; High frequency digital circuits should have thinner and shorter wiring. 4) Widen the power and ground wires to reduce their impedance. 5) Try to use 45 ° line instead of 90 ° line wiring to reduce the external transmission and coupling of high-frequency signals. 6) The difference in the length of the address or data cable should not be too large, otherwise the short part should be compensated for by manually bending the cable. 7) Attention should be paid to isolation between high current signals, high voltage signals, and small signals (the isolation distance is related to the withstand voltage to be borne. Generally, the distance on the board should be 2mm when it is 2kV, and it should be increased proportionally above this. For example, if it is to withstand a withstand voltage test of 3kV, the distance between high and low voltage lines should be above 3.5mm. In many cases, to avoid creepage, slots are also opened between high and low voltage on the PCB board). 3. Circuit design in PCB boards When designing electronic circuits, more consideration is given to the actual performance of the product, rather than the electromagnetic compatibility (EMC) and electromagnetic interference (EMI) suppression and electromagnetic anti-interference characteristics of the product. When using circuit diagrams for PCB layout, necessary measures must be taken to achieve electromagnetic compatibility, that is, adding necessary additional circuits on the basis of the circuit diagram to improve the electromagnetic compatibility performance of the product. In actual PCB design, the following circuit measures can be adopted: 1) A resistor can be connected in series on the PCB wiring to reduce the speed of the control signal at both the online and offline edges. 2) Try to provide some form of damping for relays, etc. (high-frequency capacitors, reverse diodes, etc.). 3) The signal entering the PCB board should be filtered, and the signal from the high noise area to the low noise area should also be filtered. At the same time, a series terminal resistor method should be used to reduce signal reflection. 4) The useless end of MCU should be connected to the power or ground through corresponding matching resistors, or defined as the output end. The power and ground terminals on the integrated circuit should be connected and not suspended. 5) The input end of the unused gate circuit should not be suspended, but should be connected to the power or ground through corresponding matching resistors. The idle operational amplifier has a positive input terminal grounded and a negative input terminal connected to the output terminal. 6) Install a high-frequency decoupling capacitor for each integrated circuit. A small high-frequency bypass capacitor should be added to the edge of each electrolytic capacitor. 7) Use large capacity tantalum capacitors or polyester capacitors instead of electrolytic capacitors as charging and discharging energy storage capacitors on PCB boards. When using tubular capacitors, the casing should be grounded.

1. Composite printed circuit board substrate Composite substrate is also called [powder board]. The most common composite substrate copper-clad laminates currently on the market include single and double sided CEM-1, CEM-3 semi glass fiber board, 22F, etc., with wood pulp fiber paper or cotton pulp fiber paper as the reinforcing material. At the same time, fiberglass cloth is used as surface reinforcement material, and the two materials are made of flame retardant epoxy resin. 2. Phenolic PCB circuit board paper substrate Phenolic substrate is also called [flame retardant board]. The most common ones include V0 board, cardboard, FR-1, FR-2, FE-3, 94HB, XPC, etc., because its main material is wood pulp fiber paper, which has been A PCB board that is pressurized and synthesized. Its main features are low cost, low price, and relatively low density. The disadvantage is that it is not fireproof. It is mainly used in children's consumer electronics. 3. Glass fiber PCB substrate Fiberglass board is also called [epoxy board, fiber board]. It is mainly made of epoxy resin as adhesive and fiberglass cloth as reinforcement material. PCB boards made of this kind of board have strong fire resistance, height resistance and are not affected by the environment. Small, the most commonly used substrates are double sided PCB and multi layer PCB. Conventional processes: lead free tin spray, green oil folding, 1.6 thick plate, suitable for various power boards, control boards, communications, instruments It is widely used in instrumentation, automobile and computer industries. 4. LED circuit board aluminum substrate LED board is quite special. It is a metal based copper clad laminate with good heat dissipation function. Generally, a single panel consists of a three layer structure, which are circuit layer (copper foil), insulation layer and metal base layer. For high end use, there are also double sided designs with a structure of circuit layer, insulation layer, aluminum base, insulation layer, and circuit layer. A very few applications are multi layer boards, which can be made of ordinary multi layer boards laminated with insulation layers and aluminum bases. 5. Other substrates In addition to the three commonly seen above, there are also metal substrates and build up multilayer boards (BUM). It is worth noting that we often see the letters KB printed on the circuit board. This is the PCB of Kingboard Company. Plate abbreviations include, in addition to Kingboard, Shengyi SL, Taiyao TUC, Guoji GDM, Changchun L, Changxing EC, Hitachi H, etc. In addition to the above types of substrates, there are also built up multi layer boards and metal substrates. Many times we will see the two English letters KB on the finished PCB. It is the abbreviation of Kingboard board. In addition to Kingboard, there are also Shengyi SL, Taiyao TUC, Guoji GDM, Changchun L, Changxing EC, Hitachi H, etc. Boards like this can guarantee the performance of the product from the source. Of course, the management of the production line and the experience of the staff are also very important.

1. As mentioned above, generally electrolytic copper foil is a product processed by wool foil electroplating or copper plating. If the peak value during the wool foil production process is abnormal, perhaps the crystallization branching of the coating during the galvanizing/copper plating process is poor, and the peeling strength of the copper foil itself is insufficient. When bad foil is pressed into a thin sheet to form a printed circuit board, copper wires can fall under the impact of external forces as they penetrate the electronics factory. When the rough surface of the copper foil (that is, the contact surface with the substrate) is peeled off, this poor copper extrusion will not cause significant side corrosion, but the peeling strength of the entire copper foil will be very poor. 2. Copper foil has poor adaptability to resin: Due to different resin systems, the curing agent used in some special functional laminates (such as HTg sheets) is generally PN resin. The molecular chain structure of the resin is simple and the degree of cross linking during the curing process is low. Therefore, it is inevitable to use copper foil with special peaks to match it. When producing laminates, the copper foil used does not match the resin system, resulting in a lack of peel strength of the metal foil covered by the metal sheet, and poor peeling of the copper wire when inserted. 2. Reasons for making multi layer PCB and PCB circuit board laminates: Under normal circumstances, as long as the hot pressed high temperature part of the laminate lasts for more than 30 minutes, the copper foil and prepreg are basically completely bonded, so the adhesion between the copper foil and the substrate in the laminate is generally not affected. However, during the lamination process of stacking, if the polypropylene is contaminated or the surface of the copper foil is damaged, the bonding force between the laminated copper foil and the base material will be lacking, resulting in positioning (only applicable to large boards) or scattered Copper wire falls. However, near the offline measurement, there was no abnormality in the peel strength of the copper foil.

Regarding the production of multi layer circuit boards, you must first draw the circuit schematic diagram according to the functions that the electronic product needs to realize. There are special drawing tools, which are like understanding each component with wires. The PCB circuit board design software will generate a physical connection file based on the circuit schematic diagram and connect all the components. During actual production, the connection places are very thin copper sheets that can conduct electricity. In this way, a Printed Circuit Board is ready, and then the completed files are sent to a specialized multi-layer circuit board manufacturer for production, and the actual circuit board is made. But the multi-layer circuit board produced by the circuit board manufacturer has no components, it is just the connection of some lines. Just like an electrician wiring, leave out all the electrical appliances that need to be connected and connect all the wires. The last thing we have to do is install these components. We solder the required components to the designated positions. At this time, the entire multi-layer circuit board forms an actual working circuit, and the desired function can be realized.PCBA Circuit Board

In recent years, the rapid increase in smartphone production has driven the demand for PCB circuit boards. Especially this year, my country has become a leader in 5G. 5G mobile phones will usher in large-scale widespread replacement applications, thus bringing new growth demand to the PCB circuit board market. There are many printed circuit board manufacturers in mainland China, most of which are located in the Pearl River Delta and Jiangsu and Zhejiang regions. There are many manufacturers. Because various consumer electronic products such as mobile phones, PDAs, digital cameras, etc. are developing in the direction of thinner, smaller and multi-functional, FPC soft boards can be flexibly bent and have ever-changing shapes due to their softness, thinness and high pin density. It combines a variety of advantages and caters to the trend of thinner and more sensitive electronic products. It gradually replaces the closed ends of hard boards in some aspects and becomes the main connection accessory in electronic equipment. Today's electronic products are pursuing lightness, thinness, shortness and small size, and the FPC soft board market has broad prospects. In recent years, the rapid development of wearable devices, Internet of Things and other fields has put forward new requirements for the FPC soft board industry, and the demand for FPC series products has increased significantly. Weifu Circuit Board is a professional PCBA circuit board manufacturer. We have entered and developed in digital cameras, automotive satellite positioning equipment, LCD TVs, laptops, medical instruments, intelligent robots, mobile phones and other communication fields. We are very grateful to many customers. We support Weifu and are willing to work together with us, and welcome more customers to discuss cooperation.

With the application of PCB circuit boards in various major electronic products, PCB circuit board repair has also become a popular industry. Today, Brother Xiaojie will briefly share his views on the current PCB circuit board maintenance. At present, there are various industries that use circuit boards in our country. In the early stages of production, the production process and raw materials will be determined according to their own use needs. However, as the frequency of use of finished products increases, circuit board failures will occur more or less. In the past, there will be circuit board failures. Many people will directly replace the circuit board, but the high cost of replacing the PCB circuit board (ranging from a few thousand yuan to tens of thousands or hundreds of thousands of yuan) has also become a very headache for various companies. However, these damaged circuit boards can be repaired in China, and the repair costs are relatively affordable, accounting for only 20%-30% of new boards. For some high precision equipment that requires international ordering of boards, circuit board repairs will be more expensive. Fast. The first step: circuit board inspection At present, many users of finished equipment basically do not have the design drawings of the circuit board in their hands after a circuit board failure occurs. Many people are skeptical about PCB circuit board repair. Although various circuit boards are different, one thing remains unchanged. PCB circuit boards are composed of various integrated blocks, resistors, capacitors and other components, so damage to the PCB circuit board must be caused by damage to one or some of the components. The idea of printed circuit board repair is based on the above factors. Get up. Maintenance staff will first inspect the circuit board, find out the source of the problem step by step, and replace parts. Step Two: Parts Replacement After finding the source of the circuit board failure, the maintenance engineer will recommend corresponding replacement parts based on the performance of the original parts based on the usage conditions of the entire circuit board. Users can choose to replace them according to their own needs. The process of replacing parts is simple here. Too much explanation. Step 3: On machine testing On machine inspection of the circuit board after repair is the key to judging the success of the repair. Here, Xiao Jiege recommends that maintenance engineers gradually accumulate experience and continuously improve their level during the maintenance, testing and overhaul of PCB circuit boards. . General electronic equipment is composed of thousands of components. During maintenance and repair, it will be very time consuming and difficult to implement if you directly test and inspect every component in the PCBA circuit board one by one to find problems. very difficult. Then the correct maintenance method from the fault phenomenon to the cause of the fault is an important maintenance method. As long as the problem with the PCB circuit board is detected, repair will be easy.

In PCB circuit design, there will be times when IC needs to be replaced. Let`s share the tips when replacing IC to help designers become more perfect in PCB circuit design. 1. Direct substitution Direct substitution refers to directly replacing the original IC with other IC without any modification. The main performance and indicators of the machine will not be affected after the substitution. The principle of substitution is: the function, performance index, packaging form, pin usage, pin number and spacing of the replacement IC are the same. The same function of the IC not only means the same function, but also the same logic polarity, that is, the output and input level polarity, voltage, and current amplitude must be the same. Performance indicators refer to the IC's main electrical parameters (or main characteristic curves), maximum power dissipation, maximum operating voltage, frequency range, and various signal input and output impedance parameters that should be similar to the original IC. Substitute parts with low power need to enlarge the heat sink. 1. Replacement of the same model IC Replacement of the same type of IC is generally reliable. When installing the integrated PCB circuit, be careful not to get it in the wrong direction. Otherwise, the integrated printed circuit board circuit is likely to be burned when power is turned on. Some single in line power amplifier ICs have the same model, function, and characteristics, but the direction of the pin arrangement is different. For example, the two channel power amplifier ICLA4507 has "positive" and "reverse" pins, and its starting pin markings (color dots or pits) are in different directions: no suffix and "R" suffix, IC, etc., for example M5115P and M5115RP. 2. Substitution of ICs with the same model prefix letters and different numbers This kind of substitution can also be directly substituted with each other as long as the pin functions are exactly the same and the internal PCB circuit and electrical parameters are slightly different. For example: ICLA1363 and LA1365 are placed in the audio. The latter has a Zener diode inside IC pin 5 than the former, but everything else is exactly the same. Generally speaking, the prefix letters indicate the manufacturer and the type of PCBA circuit board. The numbers after the prefix letters are the same, and most of them can be directly replaced. But there are a few exceptions where although the numbers are the same, the functions are completely different. For example, HA1364 is a sound IC, while uPC1364 is a color decoding IC; the number is 4558, the 8-pin one is the operational amplifier NJM4558, and the 14-pin one is the CD4558 digital PCB circuit; therefore, the two cannot be replaced at all. So you must also look at the pin function. Some manufacturers introduce unpackaged IC chips and then process them into products named after their own manufacturers, as well as products improved to improve certain parameters. These products are often named with different models or distinguished by model suffixes. For example, AN380 and uPC1380 can be directly replaced, and AN5620, TEA5620, DG5620, etc. can be directly replaced. 2. Indirect substitution Indirect substitution refers to the method of slightly modifying the peripheral PCB circuit of an IC that cannot be directly replaced, changing the original pin arrangement or adding or subtracting individual components, etc., to make it a replaceable IC. Principle of substitution: The IC used for substitution can have different pin functions and shapes from the original IC, but the functions must be the same and the characteristics must be similar; the performance of the original machine should not be affected after substitution. 1. Substitution of different package ICs IC chips of the same type but with different package shapes. When replacing, just reshape the pins of the new device according to the shape and arrangement of the pins of the original device. For example, the AFTPCB circuit CA3064 and CA3064E, the former is a circular package with radial pins; the latter is a dual in line plastic package. The internal characteristics of the two are exactly the same, and they can be connected according to the pin function. The packaging forms of dual row ICAN7114, AN7115 and LA4100, LA4102 are basically the same, and the pins and heat sinks are exactly 180 degrees different. The aforementioned AN5620 dual in line 16 pin package with heat sink and TEA5620 dual in line 18 pin package have pins 9 and 10 located on the right side of the integrated PCB circuit, which are equivalent to the heat sink of the AN5620. The other pins of the two are arranged the same. Just connect pins 9 and 10 to ground. 2. PCB circuit function is the same but individual pin functions are different IC replacement Replacement can be carried out according to the specific parameters and instructions of each model of IC. For example, the AGC and video signal outputs in TVs have positive and negative polarities, which can be replaced by adding an inverter to the output end. 3. Substitution of ICs with the same plastic but different pin functions This kind of substitution requires changing the peripheral PCB circuit and pin arrangement, so it requires certain theoretical knowledge, complete information and rich practical experience and skills. 4. Some empty feet should not be grounded without permission Some pins in the internal equivalent PCB circuit and application PCB circuit are not marked. When encountering empty pins, you should not ground them without authorization. These pins are replacement or spare pins, and sometimes they are also used as internal connections. 5. Combination substitution Combination replacement is a method of recombining the undamaged PCB circuit parts of multiple ICs of the same model into a complete IC to replace malfunctioning ICs. It is very suitable for situations where the original IC cannot be purchased. However, it is required that the intact PCB circuit inside the IC used must have interface pins. The key to indirect substitution is to find out the basic electrical parameters of the two interchangeable ICs, the internal equivalent PCB circuit, the functions of each pin, and the connection relationship between the IC components. Please pay attention during actual operation. (1) The numbering sequence of the integrated PCB circuit pins must not be connected incorrectly; (2) In order to adapt to the characteristics of the replaced IC, the components of the peripheral PCB circuit connected to it must be changed accordingly; (3) The power supply voltage must be consistent with the replaced IC. If the power supply voltage in the original PCB circuit is high, try to reduce the voltage; if the voltage is low, it depends on whether the replacement IC can work; (4) After replacement, the static operating current of the IC must be measured. If the current is much greater than the normal value, it means that the PCB circuit may be self excited, and decoupling and adjustment must be carried out. If the gain is different from the original, the feedback resistor value can be adjusted; (5) The input and output impedance of the IC after replacement must match the original PCB circuit; check its driving capability; (6) When making changes, make full use of the pin holes and leads on the original PCB circuit board. The external leads must be neat and tidy to avoid crossing before and after, so as to check and prevent PCB circuit self excitation, especially to prevent high frequency self excitation; (7) Before powering on, it is best to connect a DC ammeter in series to the power supply Vcc loop, and observe whether the change in the total current of the integrated PCB circuit is normal from large to small with the resistance of the voltage reducing resistor. 6. Replace IC with discrete components Sometimes discrete components can be used to replace damaged parts of the IC to restore functionality. Before replacement, you should understand the internal functional principles of the IC, the normal voltage of each pin, the waveform diagram, and the working principle of the PCB circuit composed of peripheral components. Also consider: (1) Can the signal be taken out from the IC and connected to the input end of the peripheral PCB circuit: (2) Whether the signal processed by the peripheral PCB circuit can be connected to the next level inside the integrated PCB circuit for reprocessing (signal matching during connection should not affect its main parameters and performance). If the mid amplifier IC is damaged, judging from the typical application PCB circuit and internal PCB circuit, it consists of audio mid amplifier, frequency identification and frequency amplification stages. The signal input method can be used to find the damaged part. If the audio amplification part is damaged, discrete components can be used replace.

In the process of designing high speed PCB circuit board, seemingly simple via holes that leave no sound are likely to bring significant negative effects to the circuit board. Today, Weifu Precision Manufacturer will talk to you about how to reduce the adverse effects of parasitic effects in through-hole design in high speed PCB circuit board: 1. The pins of the power supply and ground should be perforated nearby, and the shorter the lead between the vias and pins, the better, as they can lead to an increase in inductance. At the same time, the leads of the power and ground should be as thick as possible to reduce impedance. 2. The signal routing on the PCB circuit board should be minimized by not changing layers, which means unnecessary through holes should be avoided as much as possible. 3. The use of thinner PCB circuit board is beneficial for reducing the two parasitic parameters of via. 4. Considering both cost and signal quality, choose a reasonable size for the through-hole. For example, for the design of 6-10 layer memory module PCB circuit board, it is better to use 10/20Mil (drilled/soldered) through holes. For some high density small-sized boards, 8/18Mil through holes can also be used. Under current technological conditions, it is difficult to use smaller through-holes. For the via of the power or ground wire, larger sizes can be considered to reduce impedance. 5. Place some grounded vias near the vias of the signal switching layer to provide the nearest circuit for the signal. Even a large number of extra grounding vias can be placed on the multi layer PCB. Of course, flexibility and versatility are also required during design. The through-hole model discussed earlier refers to the situation where each layer has solder pads, and sometimes we can reduce or even remove the solder pads of certain layers. Especially in cases where the through-hole density is very high, it may lead to the formation of a groove in the copper layer that separates the circuit. To solve this problem, besides moving the position of the through-hole, we can also consider reducing the size of the solder pad in the copper layer. By reading the above content, I believe everyone has gained some understanding of through-hole design in high-speed printed circuit board. Weifu Precision has shared this with you. If you want to learn more related information, you can consult our customer service personnel online or visit Weifu's official website

The design of a Printed Circuit Board is a complex and meticulous process that requires consideration of multiple factors to ensure the effectiveness, reliability, and performance of the design. Choose appropriate materials for the combination of soft and hard boards according to the application requirements. Consider the electrical, mechanical, thermal, and processing properties of the materials to ensure that the selected materials meet the design requirements. Layer planning requires a reasonable planning of multi layer PCB based on circuit complexity and signal transmission requirements. Ensure reliable electrical connections between layers, while also considering heat dissipation and wiring space. When wiring, try to minimize the length and intersection of the wiring to reduce noise and interference. Pay attention to the rationality of wiring width and spacing to meet the requirements of electrical performance and mechanical strength. Reasonable grounding design is crucial for suppressing electromagnetic interference and improving signal quality. Ensure that the grounding wire width is sufficient, the grounding path is short and direct, and avoid forming a loop. Consider the heat generated during the operation of the Printed Circuit Board Assembly, and ensure that the components work within the allowable temperature range through reasonable thermal design and heat dissipation layout.

The circuit layer in a double-sided aluminum substrate is mainly composed of copper foil, which is mainly used for conductivity. This layer is the transmission path of electronic signals, responsible for connecting electronic components together to form a complete circuit system. Through the circuit layer, current can flow throughout the entire printed circuit board, thereby achieving the normal operation of the equipment. Due to the wiring on both sides of the double-sided aluminum substrate, it is necessary to use appropriate wiring connection techniques, such as hole conduction technology, to connect the circuit layers on both sides to ensure smooth current flow. The layout and connection of circuit layers are crucial in the design and manufacturing process of Double Sided PCB, as they directly affect the performance and reliability of aluminum substrates. So when designing and manufacturing double sided PCB, it is necessary to carefully design and optimize the circuit layers to ensure that they can meet the needs of the equipment and have good conductivity.

Whether it is the layout of the devices on the PCB board or alignment and so on have specific requirements. For example, the input and output lines should try to avoid parallel, so as not to generate interference. Two signal lines parallel alignment is necessary to add ground isolation, two adjacent layers of wiring to try to perpendicular to each other, parallel easy to produce parasitic coupling. Power and ground should be divided as far as possible in two layers perpendicular to each other. Line width, the digital circuit PCB available wide ground line to make a circuit, that is, to form a ground network (analog circuits can not be used in this way), with a large area of copper laying. The following is a description of the principles and some details that need to be taken into account in the design of the microcontroller control board. 1.Component layout In terms of the layout of components, the components related to each other should be placed as close as possible, for example, the clock generator, crystal, CPU clock input are prone to noise, they should be placed closer to some. For those devices prone to noise, small current circuits, high current circuit switching circuits, etc., should be as far away as possible from the logic control circuit and storage circuit of the microcontroller (ROM, RAM), if possible, these circuits can be made into a separate circuit board, which is conducive to anti-interference, improve the reliability of the circuit work. 2.Decoupling Capacitor Try to install decoupling capacitors next to key components, such as ROM, RAM and other chips. In fact, PCB board alignments, pin connections and wiring may contain large inductive effects. Large inductors may cause severe switching noise spikes on the Vcc alignment. The only way to prevent switching noise spikes on the Vcc alignment is to place a 0.1uF electronic decoupling capacitor between VCC and power ground. If a surface mount component is used on the PCB, a chip capacitor can be used directly adjacent to the component and fixed on the Vcc pin. It is best to use porcelain chip capacitors, this is because this capacitor has a low electrostatic loss (ESL) and high frequency impedance, in addition to the dielectric stability of this capacitor over temperature and time is also very good. Try not to use tantalum capacitors because of its high impedance at high frequencies. The following points need to be noted when placing decoupling capacitors. (1) Connect an electrolytic capacitor of about 100uF across the power input of the PCB, or better yet, a larger capacitance if size allows. (2) In principle, a 0.01uF ceramic chip capacitor needs to be placed next to each IC chip. If the board gap is too small to fit, a tantalum capacitor of 1~10 can be placed every 10 chips or so. (3) For components with weak immunity to interference and large current changes when turned off, and storage components such as RAM and ROM, a decoupling capacitor should be connected between the power line (Vcc) and ground. (4) The leads of the capacitors should not be too long, especially the high-frequency bypass capacitors should not come with leads. The following points need to be noted when placing decoupling capacitors. 3. Ground design In microcontroller control systems, there are many types of grounds, including system ground, shield ground, logic ground, analog ground, etc. Whether the ground is laid out properly will determine the board's immunity to interference. When designing grounds and grounding points, the following issues should be considered. (1) Logical and analog grounds should be wired separately and not combined, connecting their respective grounds to the corresponding power ground. The analog ground should be as thick as possible during design, and the grounding area of the lead end should be as large as possible. In general, for the input and output analog signals, it is best to isolate them from the microcontroller circuitry via optocouplers. (2) In the design of the printed circuit version of the logic circuit, the ground should form a closed-loop form to improve the circuit's immunity to interference. (3)(3) The ground wire should be as thick as possible. If the ground wire is very thin, the ground resistance will be larger, causing the ground potential to change with the current, resulting in an unstable signal level and leading to a decrease in the circuit's immunity to interference. In the case of wiring space allows, to ensure that the width of the main ground line at least 2 ~ 3mm or more, the ground line on the component pins should be about 1.5mm. (4)Pay attention to the choice of grounding point. When the signal frequency on the board is lower than 1MHz, the influence of electromagnetic induction between the wiring and components is very small, and the loop current formed by the grounding circuit has a greater impact on the interference, so a point of grounding should be used so that it does not form a loop. When the signal frequency on the board is higher than 10MHz, the ground impedance becomes large due to the obvious inductive effect of the wiring, and the loop current formed by the grounding circuit is no longer a major problem at this time. Therefore, multiple points of grounding should be used to minimize the ground impedance. 4. Other (1) The layout of the power cord in addition to the size of the current to try to thicken the width of the alignment, in wiring should also make the power cord, ground line alignment direction and data line alignment body in line with the wiring work at the end of the ground line will be the bottom of the board without the alignment of the pavement, these methods help to enhance the anti-interference ability of the circuit. (2) The width of the data lines should be as wide as possible to minimize impedance. The width of the data lines should be at least 0.3mm (12mil), and it would be better if 0.46~0.5mm (18mil~20mil) is used. (3) Since one vias of the board will bring about 10pF of capacitive effect, which will introduce too much interference for high frequency circuits, the number of vias should be reduced as much as possible when wiring. Then again, too many vias can cause the mechanical strength of the board to be reduced.

Single-sided circuit board inspection defect definition. 1, PT surface: soldering surface. 2, MT surface: parts assembly surface. 3, light defects: because of its poor quality, may make the performance of the printed wiring board has been reduced, life has been shortened. 4, minor defects: due to its poor quality may reduce the value of goods, but does not affect the performance and life of the printed wiring board, etc.. 5, conical hole: due to the stamping model of the upper type perforation and the lower type of the hole gap is too large, stamping perforated parts, such as the shape of the hole section to the assembly side of the parts open horn shape. 6, heavy defects: due to its poor quality so that the printed circuit board can not be used for the intended purpose. 7, conical hole: due to stamping model of the upper type of perforation and the lower type of hole gap is too large, stamping perforated parts, such as the hole cross-sectional shape to the assembly side of the parts open horn shape.

Many customers looking for PCB circuit board manufacturers , do not know how to choose, not a careful selection of small processing plants, small workshops, talk in front of a good, the next second turn hand to place orders to other manufacturers of strength for prototype production, so that a lot of wasted time. When looking for PCB circuit board manufacturers, be sure to go to the factory for a survey, so that you can actually identify the strength of the manufacturer. How to identify the strength of PCB circuit board manufacturers? Today Wei Fu circuit board to teach you how to identify the strength of the manufacturer, to eliminate such things to save your time and costs? First of all, before choosing a PCB board manufacturer, you have to understand their company's situation, such as whether the processing process is mature, whether the company's scale system is very comprehensive, whether the company's equipment is used equipment, whether there is a UL certificate and the company's cultural words service system, these are the first thing we must be clear, which has a clear understanding of these after you can choose to go to the factory survey, so you can say is This can be said to be nine out of ten, both to save your time costs, but also for you to avoid the possibility of choosing some small factory. Yes, this is your choice of a PCB circuit board manufacturer in the early said to understand things, do not just think that the price is cheap what is not important, so that you bring the hidden danger is unpredictable, we Wei Fu circuit board can be so many manufacturers say recognized, are because we are qualified in all the above conditions, so customers are assured that down-to-earth cooperation with us, if you have the need to call us for advice, we We will be happy to develop a reasonable PCB board solution for you. By reading the above, I think we all have an understanding of how to identify PCB circuit board strength manufacturers, Bao Wei Fu circuit board for you to share this, if you want to know more information, you can consult our customer service staff online, or enter the Dongguan Wei Fu Circuit Technology Co.

In the process of designing high-speed PCB circuit boards, the seemingly simple over-hole, a silent is likely to bring a great negative effect on the circuit board. Today WeiFu circuit board manufacturers to tell you how to over-hole design in the high-speed PCB circuit board, to reduce the adverse effects of the parasitic effect of the over-hole:. 1, the power supply and ground pins to be close to the over-hole, the shorter the lead between the over-hole and the pin, the better, because they can lead to an increase in inductance. At the same time, the power supply and ground leads should be as thick as possible to reduce impedance. 2, PCB circuit boards on the signal alignment as far as possible without changing layers, that is, try not to use unnecessary holes. 3, the use of thinner PCB circuit boards to help reduce the two parasitic parameters of the vias. 4, from both the cost and signal quality considerations, choose a reasonable size of the hole size. For example, for the 6-10 layer memory module PCB circuit board design, the choice of 10/20Mil (drill / pad) over-hole better, for some high-density small size of the board, you can also try to use 8/18Mil over-hole. Under the current technical conditions, it is difficult to use smaller size vias. For the power supply or ground vias can be considered to use larger sizes to reduce impedance. 5, in the signal to change the layer near the vias placed some ground vias, in order to provide the nearest circuit for the signal. You can even place a large number of redundant ground vias on the PCB board. Of course, in the design also needs to be flexible and versatile. The previously discussed vias model is the case of each layer has pads, there are times when we can reduce or even remove the pads of some layers. Especially in the case of a very high density of vias, which may lead to the formation of a circuit break in the copper layer, to solve such problems in addition to moving the location of the vias, we can also consider reducing the size of the vias in the copper layer of the pads. By reading the above, I think we all have an understanding of the high-speed PCB circuit board in the over-hole design, Wei Fu circuit board to share this, if you want to know more about the information, you can consult our customer service staff online, or enter the Wei Fu official website Oh!

In recent years, the rapid increase in the production of smart phones has driven the demand for PCB Circuit Boards. Especially this year, China has become the leader of 5G, 5G cell phones will usher in a large-scale throughout the replacement of the use, thus bringing a new increase in demand for PCB circuit board shopping malls. In mainland China, there are many PCB circuit board manufacturers, most of which are located in the Pearl River Delta region and Jiangsu and Zhejiang regions. We have a lot of manufacturers in Shenzhen. Because cell phones, PDA, digital cameras and other consumer electronics products are thinner, smaller and multi-functional direction, FPC soft board because of soft, thin, high pin density, can be sensitive to zigzag, the shape of a variety of advantages in one, in line with the trend of thin and sensitive electronic products, and gradually replace the hard board in some aspects of the closed end, become the main articulation accessories in electronic equipment. Today's electronic products are looking for light, thin, short, small planning, FPC soft board market prospects. In recent years, wearable devices, the Internet of Things and other areas of rapid development, the FPC soft board industry to put forward new requirements, FPC series products demand increased significantly. WeiFu circuit board as a professional PCB circuit board manufacturer, we have entered and developed in digital cameras, automotive satellite directional positioning equipment, LCD TVs, notebook computers, medical instruments, intelligent robots, cell phones and other communication categories, thank you very much for the support of many customers to Hengcheng and, willing to work with us, welcome more customers to discuss collaboration.