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The direct cause of temperature rise in printed circuit boards is due to the presence of power consuming devices in the circuit. Electronic devices all have varying degrees of power consumption, and the heating intensity varies with the magnitude of power consumption. Two phenomena of temperature rise in printed circuit boards: (1) Local temperature rise or large-scale temperature rise; (2) Short term or long-term temperature rise. When analyzing PCB thermal power consumption, it is generally analyzed from the following aspects 1. Electrical power consumption (1) Analyze power consumption per unit area; (2) Analyze the distribution of power consumption on PCB circuit boards. 2. Structure of Printed Circuit Board (1) The size of the printed circuit board; (2) The material of the printed circuit board. 3. Installation method of printed circuit board (1) Installation method (such as vertical installation, horizontal installation); (2) Sealing condition and distance from t
1. Lack of planning As the saying goes, "If a person doesn't have a plan beforehand, they will find trouble and come knocking on their door." This also applies to PCB design. One of the many steps that make PCB design successful is to choose the appropriate tool. Today's PCB design engineers can find many powerful and easy-to-use electronic design automation (EDA) software suites on the market. Each model has its own unique capabilities, advantages, and limitations. Additionally, it should be noted that no software is foolproof, so issues such as mismatched component packaging are bound to occur. It is possible that there is no single tool that can meet all your needs. Nevertheless, you still need to put in effort to research in advance and strive to find the best product that best suits your needs. Some information on the internet can help you get started quickly. 2. Poor communication Although outsourcing PCB design to other manufacturers is becoming increasingly common and
1. Prevent burrs and scratches on the surface of the PCB board. 2. Plays a role in heat dissipation and cleaning the drill bit. 3. It can guide the drill bit to drill into the track of the PCB board to improve the accuracy of drilling. Aluminum sheets require a high thermal conductivity to quickly remove the heat generated during drilling and reduce the temperature of the drill bit. It is recommended to use aluminum sheets with a thickness of 0.15-0.2mm or aluminum alloy composite aluminum sheets with a thickness of 0.15-0.35mm to effectively prevent the drill bit from breaking due to poor chip removal caused by high temperatures during drilling. 3. The quality of copper-clad board material is that the fiberglass cloth of the board material is coarse, and the bonding force is not good, which can also have a significant impact on the broken drill bit. If the resin polymerization of the board is not complete, it is easy to produce a lot of adhesive residue on the hole wall, poor
Despite the cost factors mentioned above, the price of flexible assembly is decreasing and becoming closer to traditional rigid circuits. The main reason is the introduction of updated materials, improved production processes, and structural changes. The current structure enhances the thermal stability of the product, with few material mismatches. Some updated materials can produce more precise lines due to the thinner copper layer, making the components lighter and more suitable for fitting into small spaces. In the past, copper foil was adhered to a medium coated with adhesive using roller pressing technology. Nowadays, copper foil can be directly generated on the medium without using adhesive. These technologies can produce copper layers several micrometers thick, resulting in Precision lines with a width of 3m.1 or even narrower. After removing certain adhesives, flexible circuits have flame retardant properties. This can accelerate the uL certification process and further reduc
If the circuit design is relatively simple, the total volume is not large, and the space is suitable, traditional interconnection methods are mostly much cheaper. If the circuit is complex, processes many signals, or has special electrical or mechanical performance requirements, flexible circuits are a good design choice. When the size and performance of an application exceed the capacity of a rigid circuit, flexible assembly is the most economical method. A 12 mil solder pad with a 5 mil through-hole and a flexible circuit with 3 mil lines and spacing can be made on a thin film. Therefore, directly mounting chips on thin films is more reliable. Because it does not contain flame retardants that may be sources of ion drilling pollution. These films may have protective properties and cure at higher temperatures, resulting in higher glass transition temperatures. The reason why flexible materials save costs compared to rigid materials is that they eliminate the need for connectors. H
Introduction to PCB Warpage 1、 Standards and testing methods for warpage According to the American IPC-6012 (1996 edition) "Identification and Performance Specification for Rigid Printed Boards", the maximum allowable warpage and distortion for surface mounted printed boards is 0.75%, while other types of boards are allowed at 1.5%. This increases the requirement for surface mounted printed boards compared to IPC-RB-276 (1992 edition). At present, the allowable warpage for electronic assembly plants, whether it is double-layer or multi-layer boards, is 1.6mm thick, usually 0.70-0.75%. For many SMT and BGA boards, the requirement is 0.5%. Some factories are advocating to increase the warpage standard to 0.3%. The testing method for warpage follows GB4677, 5-84 or IPC-TM-6502422B. Place the board on a verified platform and insert the testing needle into the area with the maximum warpage. The warpage of the printed board can be calculated by dividing the diameter of the testing needle
What are the classifications of PCB board materials and ceramic high-frequency board series? Let's introduce them in detail below: RO3000 series: PTFE circuit materials based on ceramic filling, with models including RO3003, RO3006, RO3010, and RO3035 high-frequency laminates. RT6000 series: PTFE circuit material based on ceramic filling, designed for electronic and microwave circuits that require high dielectric constant. The models include RT6006 with a dielectric constant of 6.15 and RT6010 with a dielectric constant of 10.2. TMM series: composite materials based on ceramics, hydrocarbons, and thermosetting polymers, models: TMM3, TMM4, TMM6, TMM10, TMM10i, TMM13i. and so on
Poor solderability of circuit board holes will result in virtual soldering defects, affecting the parameters of components in the circuit, leading to unstable conduction of multi-layer board components and inner wires, and causing the entire circuit function to fail. The so-called weldability refers to the property of the metal surface being wetted by molten solder, that is, the formation of a relatively uniform and continuous smooth attached film on the metal surface where the solder is located. The main factors affecting the solderability of printed circuit boards are: (1) the composition of the solder and the properties of the soldered material. Solder is an important component of the welding chemical treatment process, which is composed of chemical materials containing flux. The commonly used low melting point eutectic metals are Sn-Pb or Sn-Pb-Ag. The impurity content should be controlled in a certain proportion to prevent the oxide generated by impurities from being dissolve
In terms of layout, when the circuit board size is too large, although welding is easier to control, the printed lines are longer, the impedance increases, the noise resistance decreases, and the cost increases; If it is too small, the heat dissipation will decrease, and welding will be difficult to control, making it easy for adjacent lines to interfere with each other, such as electromagnetic interference from circuit boards. Therefore, it is necessary to optimize the PCB board design: (1) Shorten the connection between high-frequency components and reduce EMI interference. (2) Components with heavy weight (such as exceeding 20g) should be fixed with brackets and then welded. (3) Heating elements should consider heat dissipation issues to prevent significant surface damage to the components Δ Defects and rework caused by T should keep the thermistor away from the heat source.
(1) Adapting to a wide range of dimensions, without the need for manual hanging, achieving full automation of operations, is extremely beneficial for improving and ensuring that the operation process does not damage the surface of the substrate, and for achieving large-scale production. (2) In the process review, there is no need to leave a clamping position, which increases the practical area and greatly saves the loss of raw materials. (3) Horizontal electroplating adopts full process computer control to ensure the uniformity of the surface and hole coating of each printed circuit board under the same conditions. (4) From a management perspective, electroplating tanks can be fully automated in terms of cleaning, adding and replacing plating solution, without causing management issues to spiral out of control due to human errors. (5) As can be measured from actual production, the use of multi-stage horizontal cleaning in horizontal electroplating greatly saves the amount of cl
Excessive micro etching can cause substrate leakage at the pore opening, resulting in foaming around the pore opening; Insufficient micro etching can also cause insufficient bonding force, leading to foaming phenomenon; Therefore, it is necessary to strengthen the control of micro erosion; The micro etching depth for general copper deposition pre-treatment is 1.5-2 microns, and the micro etching depth for pattern electroplating pre-treatment is 0.3-1 microns. If conditions permit, it is best to control the micro etching thickness or rate through chemical analysis and simple experimental weighing methods; In general, the color of the slightly corroded board surface is bright, uniform pink, and without reflection; If the color is uneven or there is reflection, it indicates that there is a quality hazard in the pre-treatment of the process; Pay attention to strengthening inspections; In addition, the copper content of the micro etching tank, the temperature of the tank liquid, the loa
On automated surface mount lines, if the circuit board is uneven, it can cause inaccurate positioning, prevent components from being inserted or attached to the holes and surface mount pads of the board, and even damage the automatic insertion machine. The circuit board with installed components bends after soldering, making it difficult to trim the component pins flat and tidy. The board cannot be installed on the chassis or socket inside the machine, so it is also very troublesome for the assembly plant to encounter board warping. At present, surface mount technology is developing towards high precision, high speed, and intelligence, which puts higher requirements on the flatness of PCB boards, which are home to various components. The IPC standard specifically states that the maximum allowable deformation for PCB boards with surface mount devices is 0.75%, while the maximum allowable deformation for PCB boards without surface mount devices is 1.5%. In fact, in order to meet the
As the name suggests, a multi-layer circuit board can only be called multi-layer if it has two or more layers, such as four, six, eight, and so on. Of course, some designs have three or five layer circuits, also known as multi-layer PCB circuit boards. A conductive wiring diagram larger than a two-layer board, with insulating substrates separating the layers. After each layer of wiring is printed, it is then pressed together to overlap each layer of wiring. Afterwards, drilling holes will be carried out to achieve conductivity between each layer of the line. The advantage of multi-layer PCB circuit boards is that the circuits can be distributed and wired within multiple layers, allowing for the design of more precise products. Or smaller products can be achieved through multi-layer boards. For example, products with larger volumes such as mobile phone circuit boards, mini projectors, and recording pens. In addition, multiple layers can increase the flexibility of the design, allowi
After the final product inspection, the PCB board can be vacuum packaged and stored for shipment. So why do PCB boards need vacuum packaging? How to store after vacuum packaging? How long is its shelf life? Why do PCB boards need vacuum packaging? Although this issue is small, it is a matter that many circuit board manufacturers attach great importance to. Because once the PCB board is not sealed properly, its surface gold deposition, tin spraying, and solder pad areas will oxidize and affect welding, which is not conducive to production. So, how should PCB boards be stored? A circuit board, unlike other products, cannot come into contact with air and water. Firstly, the vacuum of the PCB board cannot be damaged. When packing, a layer of bubble film needs to be wrapped around the edge of the box. The water absorption of the bubble film is relatively good, which plays a good role in moisture-proof. Of course, moisture-proof beads cannot be missing. Then classify and label the emis
In the process of PCB gold plating, what aspects and measures can we take to reduce the consumption of gold salts and achieve maximum product benefits? The gold layer has characteristics such as corrosion resistance, high conductivity, good weldability, low and stable contact resistance, high temperature resistance, soft texture, and wear resistance. Meanwhile, after alloying with other metals such as carbon and iron, gold has higher hardness and better wear resistance. With the rise of market gold prices, the cost of gold plating has also become a key concern for enterprises. The consumption of gold salt in electroplating gold wire mainly includes two aspects: the consumption of graphic gold layer on printed circuit board and the consumption of bath solution taken out. Excessive thickness of the gold plating layer or excessive amount of liquid carried out from the tank can lead to waste of gold salt and result in ineffective gold salt consumption costs. In addition, the current
The first thing that comes to mind when measuring the technological level of a circuit board manufacturer is the number of layers for producing and processing circuit boards. Therefore, multi-layer circuit boards have strict process requirements in the production process, and multi-layer circuit boards need to sink copper into the holes to make the through holes have copper, becoming through holes. However, during the production process, occasional inspections may reveal that there is no copper or copper is unsaturated in the hole after copper deposition. What is the reason for the lack of copper in the hole? What methods can be improved? 1. Drill dust plugs or holes that are coarse. 2. When depositing copper, there are bubbles in the solution and no copper has settled in the hole 3. There is circuit ink inside the hole, no protective layer is applied, and there is no copper in the hole after etching. 4. If the acid and alkali solution inside the hole is not cleaned thoroughly
With the rapid development of mobile phones, electronics, communication industries, and other industries, the PCB circuit board industry is also constantly growing and growing rapidly. The requirements for the number of layers, weight, precision, materials, line width, line spacing, reliability, and other aspects of circuit boards are becoming increasingly high. 1 Selection criteria for printed wire width: The minimum width of printed wire is related to the current flowing through the wire. If the wire width is too small, the resistance of the newly printed wire will be high, and the voltage drop on the wire will also be large, affecting the performance of the circuit. If the wire width is too wide, the wiring density will not be high, and the board area will increase. In addition to increasing costs, it is also not conducive to miniaturization If the current load is calculated at 20A/square millimeter, when the thickness of the copper foil is 0.5MM (usually so much), the current
Flexibility and reliability of FPC flexible circuit boards At present, there are four types of FPC: single-sided, double-sided, multi-layer flexible board, and rigid flexible board. ① Single sided flexible board is the lowest cost printed board when it does not require high electrical performance. When wiring on one side, a single-sided flexible board should be selected. It has a layer of chemically etched conductive patterns, and the conductive pattern layer on the flexible insulation substrate surface is rolled copper foil. The insulation substrate can be polyimide, polyethylene terephthalate, aramid fiber ester, and polyvinyl chloride. ② Double sided flexible board is a conductive pattern made by etching one layer on each side of the insulating substrate film. Metallized holes connect the patterns on both sides of the insulating material to form a conductive path, in order to meet the design and functional requirements of flexibility. And the covering film can protect single an
The rapid development of industries such as mobile phones, electronics, and communication has also led to the continuous growth and expansion of the PCB circuit board industry. People have increasingly high requirements for the number of layers, weight, precision, materials, color, reliability, and other aspects of electronic components. But due to With the rapid development of industries such as mobile phones, electronics, and communication, as well as the continuous growth and expansion of the PCB circuit board industry, people have increasingly high requirements for the number of layers, weight, precision, materials, color, reliability, and other aspects of electronic components. However, due to fierce market price competition, the cost of PCB board materials is also on the rise, and more and more manufacturers are monopolizing the market with low prices in order to enhance their core competitiveness. However, behind these ultra-low prices, they are obtained by reducing materi
Introduction to PCB surface treatment tin spraying process PCB tin spraying, also known as hot air leveling, is an important process treatment in the production of PCB circuit boards. PCB circuit board tin spraying mainly includes lead-free tin spraying and lead tin spraying, which are also commonly used and widely used in circuit board manufacturers PCB tin spraying, also known as "hot air leveling", is an important process treatment in the production of PCB circuit boards. There are two main types of PCB tin spraying: lead-free tin spraying and lead tin spraying, which are also commonly used and widely used in PCB manufacturers. The quality of tin spraying directly affects the quality of subsequent customer welding, so tin spraying has become a key focus of quality control for PCB manufacturers. Below, we will introduce the characteristics and related basic knowledge of PCB tin spraying types. PCB surface treatment tin spraying characteristics: Tin spraying is the most commonly
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