Smart bracelet PCB copy board should pay attention to what matters?

Smart bracelet, as a more popular form of product in the last two years, more and more attention from people, although it can not be accepted by all people, but its creation, it does make the electronic product market has produced some changes. Especially young people, the pursuit of fashion, but because the price is not pro-people. Although the smart bracelet hype is hot, but few people use it. To popularize the public, you also need to use PCB copy board reverse research technology.

　　A smart bracelet is usually composed of RF circuit unit, clock circuit unit, memory circuit unit, sensor circuit unit and main control MCU unit, etc., and the circuit PCB is usually concentrated in a smaller range, single-sided or double-sided SMD, circuit board copy board to 4 or 6 layers. We have to pay extra attention to the layout and wiring of the bracelet, and now summarize some notes for reference.

　　First, partition layout, pay attention to the alignment protection.

　　From the above PCB circuit board can be seen, the various parts of the smart bracelet circuit (marked by different color boxes) has a good partition: as the smart bracelet is a collection of digital circuit components together, in the PCB copy as long as the matching resistor and capacitor distribution, you can complete a certain function of the circuit module, which makes the PCB copy more concise and easy to find. Although some sensor circuit units use analog circuit technology for data acquisition, once the module is designed as a module, then the communication of data and the transfer of information can be completed through the corresponding connection interface.

　　In the layout of the circuit module, on the one hand, need to pay attention to the clock circuit and crystal circuit to go through the shortest path to reach the target tube teaching, on the other hand, in the clock alignment also pay attention to avoid data lines to prevent interference affect the stability of the system. In the alignment, the need for protection of key alignments, such as clock generation circuit, crystal circuit and so on whether the copper laying protection, whether the ring ground protection, etc., generally in the design will be protected, for the crystal part is required to dig copper processing.

　　Second, deal with the RF circuit.

　　Smart bracelet in use need to link with the phone, therefore, the radio frequency part is the key part, in this part of the design, must pay extra attention. Now the smart bracelet on the market is nothing more than wireless data transmission based on Bluetooth, so focus on the processing of Bluetooth RF. If the smart bracelet is only used for data transmission without the need for sound and music transmission, then low-power Bluetooth is the optimal choice, in the design, Bluetooth antenna shape, antenna layout, smart bracelet shell materials are important factors affecting the performance of the smart bracelet. In the smart bracelet PCB copy process, an excellent RF antenna engineer is particularly important.

　　Third, good ESD protection.

　　In previous articles I have also written some of the circuit ESD technology and knowledge, today it is important to say that the importance of ESD on smart bracelet products. Different countries and regions on different products or the same product ESD requirements have different standards, in order to make the product through the relevant testing, in the design of ESD protection design, after the design is completed, but also to carry out ESD testing to ensure that the product through the local market to adapt to the electronic testing.

　　Fourth, set aside system upgrade interface.

　　A smart bracelet is convenient to upgrade the function of the user or smart bracelet fanatic fans have an important significance. If a product at the appropriate time for software upgrades (may be pre-hardware design to certain functions and in order to catch up with the market software did not keep up, may also be to fix some software bugs), which indicates that the product is still in the process of non-stop research and development, which is a good psychological compensation for the user. Now there are usually two ways to upgrade the software of the smart bracelet: through the USB interface and wireless push method. As for which method to use, need to be in the pre-planning and hardware and software planning is to determine.

How to solve the technical problems in PCB copy board

If there is some micro short circuit in PCB copy. Short-circuit phenomenon of the finished PCB, using ordinary low-voltage computer board testing machine test can not ensure that it does not flow into the hands of customers to customers complaints. Usually pcb copy board manufacturers push this problem to the computer board testing machine suppliers, thus promoting the development of high voltage computer board testing machine. However, it is also impossible to guarantee 100% pass rate with high voltage board testing machine. Shenzhen RayMing how to solve this problem, through work experience we came up with the following methods for your study.

　　Sometimes the first time with low-voltage test line PCB board test all OK, the second time with 300V high-voltage test test has a short circuit. The third time and re-test with ordinary low-voltage, the second measurement of the short-circuit board is also measured as a short circuit. Using a multimeter resistance file to measure the short circuit point between the two lines solder plate point for short circuit, the average resistance value of 6.7 ohms. So it should be identified as a complete short circuit rather than a micro-short circuit. Then use a high magnification lens to check the short circuit phenomenon can not accurately check the short circuit point (should be the reason for the finished product has solder resist ink).

　　From the test process and its resistance value can be identified as: etching side etching generated by the edge, and then by the process of grinding the board so that the edge breaks down in the formation of bridging between the wires, and then printed on the green oil to make its bridge is not a complete short circuit bridging. So the first test for low voltage naturally can not measure the bridging short circuit. The second time for high-voltage first measured its micro-short circuit, and then high-voltage breakdown welding (because the copper wire is very small so do not need a lot of power to do the welding to form a short circuit. (If the test machine manufacturers can improve its short-circuit test current of the allowed power to burn off the bridge, we will be difficult to see this phenomenon). So the third low-voltage computer test board machine will be able to test the short-circuit point, and its resistance value is only an average of 6.7 ohms.

　　As mentioned before, the 300V high-voltage board testing machine also has complaints about short-circuit phenomenon, check the return of bad short circuit board to see the third measurement of bad short circuit board is the same reason. Because resist soldering (green oil) screen printing will make the lifting copper wire insulation aggravated, resulting in the use of high-voltage computer board testing machine also can not be measured, and in the handling, assembly, wave soldering and semi-finished products in the test process to make its bridge to form a short circuit. Sometimes we use low-voltage board testing machine to measure this short circuit board with bending and tapping sometimes the short circuit will disappear. In the absence of a high-voltage computer board testing machine, due to the uneasy, measured OK board and then re-tested there is a short circuit bad board. Most of the problems are in the etching side etching and graphics production and solder resist ink pretreatment line, to solve this aspect of the problem of the first two processes to solve the more difficult, mainly in the production of graphics to ensure the line width and line distance to prevent part of the line too close, etching to ensure the quality of the side etching. Reduce the phenomenon of micro-short circuit during high-voltage testing.

　　The simplest and most economical method is to purchase a new mill or improve the existing mill, using a swinging brush and volcanic ash brush or low mesh nylon brush, and then rinse with high pressure, especially the water wash section is best to have a filtering device to prevent foreign objects that can cause a short circuit to pollute the board again, the mill can remove the side of the formation of copper wire and abrupt edge (sticky dust machine also has a certain role in removing). At the same time, the new purchase of computer test machine should be selected for high pressure machine, can reduce the copy board micro-short circuit and short circuit occurred. This short-circuit phenomenon Y is also very ordinary in the single panel and high-density pcb copy board.

How to meet the challenges of PCB copy board design in the age of intelligence

Under the influence of the national policy of the two sessions to support entrepreneurship and innovation, the local electronics industry has accelerated the transformation and the opening of the intelligent era. In this great intelligent era, the upgrade of PCB copy board design technology is essential. With the expansion of the smartphone and tablet PC market, the debut of portable terminals, the development of emerging markets such as vehicle, medical and access devices, products want to achieve thinner and lighter, want to improve communication speed, want to achieve various communications at the same time, want to achieve a long time battery drive, but also faster than competitors to put products on the market, all of these require higher requirements for PCB copy, design and manufacturing, in order to To meet the challenges of the smart age of a thousand changes.

　　The new requirements of PCB copy board design in the smart era

　　The advent of the smart era not only brings convenience to the life of ordinary people, but also has a profound impact on various industries. In order to make the PCB has high reliability, it is inevitable to put forward higher requirements for PCB copy and design. For example, the requirements of intelligent products on the quality of devices, the requirements of density heat dissipation, the requirements of the ubiquitous Internet of Things communication, and the requirements of intelligent production of flexible equipment, the requirements of intelligent machinery, the requirements of complex environments, and so on. These factors should be taken into account in PCB copy board design, and professional PCB copy board companies should also continuously improve technical services such as precision PCB copy board, flexible circuit board copy board, EMC design, and SI high-speed design.

　　The role of PCB copy board software in the era of intelligence

　　What is the role of PCB copy board software in the design of intelligent product copy board? Is it a tool for reverse PCB file extraction? Is it a container for reverse schematic? How will PCB copy software comply with the trend of the times and help the new generation of intelligent product copy design in the rapidly changing technology innovation?” From 2D design to 3D PCB design, from simple double-sided copy board to high-density multilayer board copy board…these simple changes can’t fully represent the future of PCB copy board design.” Ltd. said, “to solve the current PCB copy software is the real “pain” is to achieve full customization services, and constantly improve the efficiency of research and development.”

　　Intelligent era PCB copy board design requires DRC check

　　Good PCB copyboard design begins with adequate DRC checks in the layout tool. Today’s smart era of PCB design is becoming more and more complex, DRC check is also becoming more and more complex, and there is usually a huge gap between layout designers and copy engineers, they have different design expertise, use different tools, use different units of measure, and ERC / SRC (electrical rules / simulation rules) verification to fill the gap between the two.

　　In short, the intelligent era, the complexity of PCB design will continue to improve, simple PCB copy cloning has been difficult to meet the design requirements, PCB copy is reversing the study of one-stop service system has become the trend, PCB copy should be integrated into the entire industry chain, close to customer needs, to achieve full customization services and so on.

The importance of circuit board copy for medical aspects

The important role of medical-grade circuit board copy board, medical-grade circuit board copy board is important because it can connect doctors, patients and other multiple medical subjects, to promote the parties to achieve a win-win situation; these important roles need to play a more powerful group of doctors expert support, more medical principle support and technical service support, the addition of professional-level medical team can make ordinary circuit board copy board like a tiger with wings and more features.

Circuit board copy board is generally very important to patient convenience and humanized industrial design, patient convenience aims to create excellent patient service experience, allowing patients to use the device more efficiently, and humanized industrial design to make the device more aesthetic and operable, the two can not be wasted; medical grade circuit board copy board on top of these two, more emphasis on professional medical support, more detailed requirements for diagnosis.

The reason why many of the current electronic equipment is reduced to a game tool, social tools and play tools, because of its lack of effective medical professional resources support, without the intervention of excellent professional doctors, circuit board copy board is unable to perform medical functions, more unable to obtain the profound recognition of patients, which requires circuit board pay more attention to the joint medical experts, strengthen its medical support, program design and technical support for circuit board copy board preparation, to enhance its medical application value. Enhance its medical application value.

　　Throughout the domestic circuit board copy board, it tends to pay attention to the appearance of industrial design, not much attention to medical-level applications, less professional medical personnel in the R & D team, the product into the medical concept, the available medical data can be collected, are less, which also affects the rigor of the patient’s medical diagnosis, scientific, resulting in the medical application of the circuit board copy board is relatively small, which is the need to focus on strengthening the circuit board aspects . Line board copy board needs to brighten the value of the patient’s medical diagnosis, so that the data really reflects its role, so that doctors can put forward preliminary treatment advice through remote diagnosis, the organic combination of remote diagnosis and line board copy board, its will have a more rapid development.

What is a double panel?

Double-Sided Boards This type of board has wiring on both sides, but in order to use the wires on both sides, there must be a proper circuit connection between the two sides. This circuit between the “bridge” is called a guide hole (via).

Guide holes are in the PCB, filled or coated with metal holes, which can be connected to the two sides of the wire. Because the double-sided panel is twice as large as the single-sided panel, the double-sided panel solves the difficulty of interlacing the wiring in the single-sided panel (you can pass through the hole to the other side), it is more suitable for use in more complex circuits than the single-sided panel.

What is multilayer board?

Multi-Layer Boards In order to increase the area that can be wired, multi-layer boards use more single- or double-sided wiring boards. Using a double-sided as the inner layer, two single-sided as the outer layer or two double-sided as the inner layer, two single-sided as the outer layer of the printed circuit board, through the positioning system and insulation bonding material alternately together and the conductive pattern according to the design requirements of the interconnection of the printed circuit board will become a four-layer, six-layer printed circuit boards, also known as multilayer printed circuit boards.

The number of layers of the board does not mean that there are several separate wiring layers, in special cases will add empty layers to control the thickness of the board, usually the number of layers are even, and includes the outermost two layers. Most mainframe boards are 4 to 8-layer structure, although technically it is possible to do nearly 100 layers of PCBs in theory.

Most large supercomputers use quite a few layers of motherboards, although because such computers can already be replaced by many clusters of ordinary computers, ultra-layer boards have gradually fallen out of use. Because the layers in the PCB are tightly integrated, it is generally less easy to see the actual number, but if you look closely at the motherboard, you can still see.

What kind of terminal blocks are generally used for PCBs

PCB will generally use which kind of terminal blocks which depends on whether it is according to the material to divide or style to divide, if according to the material, should be more copper terminal blocks; according to the style to divide, PCB terminals are divided into plug-in terminal blocks, direct welding terminal blocks, spring-type terminal blocks, fence type terminal blocks, should be plug-in terminal blocks and spring-type terminal blocks more.

　　Spring-type terminal block is the use of spring device of the new terminal block, has been widely used in the world of electrical and electronic engineering industry: lighting, elevator lift control, instrumentation, power, chemical and automotive power. Spring type series terminal block metal parts are spring device design, plastic body are used PA66 insulation material. Spring-type series terminal blocks are easy to operate, free maintenance and with gas-tight contact device system, that is durable and reliable and cost-effective.

　　Plug-in series terminal blocks PTB by two parts plug-in connection, part of the line will be pressed, and then inserted into the other part, which is soldered to the PCB board. This connection bottom mechanical principle, this anti-vibration design to ensure the long-term airtight connection of the product and the reliability of the use of the finished product. The assembly lugs can be added to both ends of the socket, which largely protect the tabs and prevent poor alignment of the tabs, while the socket design ensures that the socket can be inserted correctly into the female body. The sockets can also have assembly and locking fasteners. The assembly fasteners provide a more secure attachment to the PCB board, while the locking fasteners lock the female and the socket after installation. A variety of socket designs are available with different insertion methods for the masters, such as horizontal, vertical or angled towards the PCB, depending on the customer’s requirements. Both metric and standard wire gauges can be selected.

PCB open and short circuit causes and improvement methods

PCB line open, short circuit is the PCB manufacturers almost every day encounter the problem, has been plagued by production, quality management personnel, it caused by the number of insufficient shipments and replenishment, delivery delays, customer complaints, is more difficult to solve the problem of the industry. Ltd. has many years of practice in production, quality, technology and cost control, for PCB open, short circuit problems have accumulated some experience in improving the text is formed to summarize, I hope that we can discuss for your reference.

　　First of all, we will cause the main reasons for the PCB open circuit summary categorized as follows:

　 Causes of the above phenomenon analysis and improvement methods are categorized as follows:

A. Open circuit caused by the exposed substrate:

　　1、Copper clad board is scratched before it goes into storage;

　　2, copper clad board in the process of opening material was scratched;

　　3, copper clad board in the drilling process was scratched by the drill nozzle;

　　4, copper clad board in the transfer process was scratched;

　　5、The surface copper foil is touched due to improper operation when stacking the board after sinking copper;

　　6、The surface copper foil of the production board is scratched when it passes through the horizontal machine.

Improvement methods:

　　1, copper clad board in the warehouse before the IQC must carry out random inspection, check whether the board surface is scratched to reveal the base material phenomenon, if there should be timely contact with the supplier, according to the actual situation, to make the appropriate treatment.

　　2, copper laminate in the process of opening material is scratched, the main reason is the presence of hard sharps on the table of the open machine, open material when the copper laminate and sharps abrasion caused by copper foil scratches formed by the phenomenon of open base material, so the material must be carefully cleaned before the table, to ensure that the table is smooth and no hard sharps.

　　3, copper clad board in drilling by the drill nozzle scratch, the main reason is the spindle clamp nozzle is worn, or clamping nozzle within the debris is not clean, grasping the drill nozzle when the grip is not firm, the drill nozzle did not go up to the top, slightly longer than the length of the set drill nozzle, drilling when lifting the height is not enough, the machine moves when the tip of the drill nozzle scratches copper foil to form the phenomenon of exposed base material.

　　a. The chucking nozzle can be replaced by the number of times recorded by grasping the tool or according to the degree of wear of the chucking nozzle;

　　b. Clean the chucking nozzle regularly according to the operation procedures to ensure that there is no debris in the chucking nozzle.

　　4、The plate is scratched during the transfer process:

　　a, handling personnel lifting the board at one time too much, the weight is too large, the board in the handling is not lifted, but dragged up, causing the board corner and the board surface friction and scratched the board surface;

　　b, put down the board because not put neatly, in order to rearrange and push the board, causing friction between the board and the board and scratch the board surface.

　　5、After sinking copper, full plate plating after stacking the board due to improper operation is scratched:

　　After sinking copper, full plate plating storage board, because the board stacked together, there are a certain number of weight is not small, and then put down, the board angle down and coupled with a gravitational acceleration, the formation of a strong impact on the board surface, causing the board surface scratches exposed substrate.

6、The production board is scratched when passing the horizontal machine::

　　a, grinding plate machine baffle sometimes touch the surface of the plate, the edge of the baffle is generally uneven and favorable object projection, over the plate when the plate surface is scratched;

　　b, stainless steel drive shaft, due to damage into a pointed object, over the plate when the copper surface is scratched and exposed to the base material.

　　To sum up, for the phenomenon of scratching in the sunken copper after the base material, if the line is in the form of an open circuit or line gap to show, easy to judge; if the scratching in the sunken copper before the appearance of the base material, but also in the line, after the sunken copper and sunk on a layer of copper, the thickness of the copper foil of the line is significantly reduced, the back open, short circuit test is difficult to detect, so that customers may use because they can not withstand Excessive current and cause the line to be burned off, the potential quality problems and the resulting economic losses are quite large. Second, non-porous open circuit:

　　1, sunken copper non-porous;

　　2, non-porous caused by oil in the hole;

　　3, non-porous caused by excessive micro-etching;

　　4, non-porous caused by poor plating

　　5、Burning hole or dust plugging hole caused by drilling no hole.

Improvement measures:

　　1、Sink copper non-porosity:

　　a. Non-porosity caused by the rectifying agent: It is due to the imbalance or failure of the chemical concentration of the rectifying agent. The role of the whole hole agent is to adjust the electrical properties of the insulating substrate on the wall of the hole, in order to facilitate the subsequent adsorption of palladium ions, to ensure complete chemical copper coverage, if the chemical concentration of the whole hole agent is not balanced or failure, will lead to non-porosity.

　　b, activator: its main components are pd, organic acids, tin ions and chloride. The pore wall to have the metal palladium uniformly deposited on it is necessary to control all aspects of the parameters, so that it meets the requirements, we now use the activator as an example:

　　①, temperature control at 35 ~ 44 ℃, if the temperature is low caused by the palladium deposited on the density is not enough, chemical copper coverage is not complete; high temperature because the reaction is too fast, the material cost increases.

　　②, the concentration of colorimetric control at 80% to 100%, if the concentration is low, resulting in palladium deposited on the density is not enough, chemical copper coverage is incomplete; high concentration because of the reaction is too fast, the material cost increases.

　　③, in the production process to maintain the activator solution, if the degree of pollution is more serious, it will cause the palladium deposited on the hole wall is not dense, the subsequent chemical copper coverage is not complete.

　　c, accelerator: the main component is organic acid, is used to remove the pore wall adsorption of stannous and chloride compounds, revealing the subsequent reaction of the catalytic metal palladium. We now use accelerator, chemical concentration control in 0.35 ~ 0.50N, if the concentration is high to remove the metal palladium, resulting in incomplete coverage of the subsequent chemical copper. If the concentration is low, the removal of pore wall adsorption of tin and chloride compounds is not effective, resulting in incomplete coverage of the subsequent chemical copper.

　　d. The control of chemical copper parameters is the key to good or bad chemical copper coverage, taking the parameters of the potion currently used by our company as an example:

①, temperature control at 25 ~ 32 ℃, the temperature is low, the liquid activity is not good, resulting in non-porous; if the temperature exceeds 38 ℃, because the liquid reaction is fast, copper ion release is also fast, easy to cause the plate surface copper particles and rework or even scrap, then the sink copper liquid to be filtered immediately, otherwise the liquid may cause scrap.

　　②, Cu2+ control in 1.5 ~ 3.0g / L, Cu2+ content is low, the liquid activity is not good, will cause poor hole; if the concentration exceeds 3.5g / L, because the liquid reaction is fast, copper ion release is also fast, resulting in plate surface copper particles and rework or even scrap, so the sink copper liquid to immediately filter, otherwise the liquid may cause scrap Cu2+ control is mainly through the addition of sink copper A liquid for control.

　　③, NaOH control at 10.5 ~ 13.0g / L is appropriate, NaOH content is low, the liquid activity is not good, will cause poor porosity NaOH control is mainly through the addition of copper sink B liquid control, B liquid contains the liquid stabilizer, under normal circumstances A liquid and B liquid is 1:1 to add the supplement.

　　HCHO control in 4.0 ~ 8.0g / L, HCHO content is low, the liquid activity is not good, resulting in poor porosity, if the concentration exceeds 8.0g / L, because the liquid reaction is fast, the release of copper ions is also fast, resulting in plate copper particles and rework or even scrap, so the copper sink solution to be filtered immediately, otherwise the liquid may cause scrap. HCHO control is mainly through the addition of copper sink C liquid for Control, A liquid also contains HCHO composition of the liquid, so add HCHO, first calculate the amount of HCHO concentration increase when supplementing A liquid.

　　⑤, sink copper load control at 0.15 ~ 0.25ft2 / L, the load is low, the liquid activity is not good, resulting in poor porosity; if the load exceeds 0.25ft2 / L, because the liquid reaction is fast, copper ion release is also fast, resulting in plate surface copper particles and rework or even scrap, so sink copper liquid to be filtered immediately, otherwise the liquid may cause scrap. Production of the first cylinder plate must be used to drag the copper plate, the activity of the copper sink solution to activate the reaction of the subsequent copper sink products, to ensure the density of chemical copper in the hole and improve coverage.

　　Suggestions: In order to achieve a balance and stability of the above parameters, the sink copper cylinder to add A, B liquid, should be equipped with an automatic filling machine to better control the chemical composition; at the same time, the temperature also uses automatic control devices to make the sink copper line solution temperature in a controlled state.

2, hole residual wet film oil caused by non-porous:

　　a, screen printing wet film when printing a plate scraped once the bottom of the screen, to ensure that the bottom of the screen no oil pile phenomenon exists, under normal circumstances there will be no hole residual wet film oil phenomenon;

　　b, screen printing wet film when the use of 68 to 77T screen, if the wrong screen, such as ≤ 51T, the hole may leak into the wet film oil, the development of the oil in the hole may not be clean, the plating will not be plated on the metal layer and caused by non-porous. If the mesh is high, it is possible that the ink thickness is not enough, and the anti-coating is broken by the current when plating, causing a lot of metal spots between the circuits or even lead to short circuit.

　　3、Roughening excessive caused by non-porosity:

　　a, before the line if the use of chemical roughening plate, the temperature of the roughening solution, concentration, roughening time and other parameters to control, otherwise it is possible that the plate plating hole copper thickness is thin, can not withstand the copper dissolving force of the roughening solution and caused by non-porosity.

　　b. In order to strengthen the bonding force between the plating layer and the base copper, the plating pre-treatment should be chemically roughened before plating, so the temperature, concentration, roughening time and other parameters of the roughening solution should be well controlled, otherwise it may also cause the problem of non-porosity.

　　4、Plating non-porosity: a. The thickness of the plating is large:

　　a, plating when the thickness of the diameter is relatively large (≥ 5: 1), there will be bubbles in the hole, this is because the vibration force is not enough to make the air escape from the hole, it is also impossible to achieve ion exchange, so that the hole is not plated with copper / tin, etching the hole when the copper etched off will cause non-porosity.

　　b, the thickness of the diameter is relatively large (≥ 5: 1), electroplating pretreatment due to oxidation in the hole is not clean, electroplating will appear to resist the plating phenomenon, no copper / tin plating or plating on the copper / tin is very thin, etching can not resist the effect of corrosion caused by the hole of copper etched off and caused by non-porosity.

　　5、Drill nozzle burn hole or dust plugging hole non-porous

　　a, drilling nozzle life is not set, or the use of the drill nozzle wear is more serious, such as gap, not sharp, drilling due to friction and too much heat, resulting in hole wall scorching can not cover the chemical copper and cause no hole.

　　b. The suction power of the vacuum machine is not big enough, or the engineering optimization is not done well, and the hole is clogged with dust when drilling, which causes non-porosity due to not sinking on copper when chemical copper is used.

PCB copy process how to properly disassemble the integrated circuit

In the PCB copy process, we often need to disassemble the circuit board, remove the integrated circuit and other components to create a BOM list, and will be disassembled from the bare board to scan and copy the board. The integrated circuit pins are not only more dense, disassembly is often easy to make mistakes and thus damage the board, resulting in the failure of PCB copy. Therefore, in the process of PCB copy, how to correctly disassemble the integrated circuits on the PCB board becomes an important issue.

Shenzhen RayMing Technology’s senior team of professional PCB copy board companies said that PCB copy board is very much focused on technology and experience, especially in the disassembly of integrated circuits, but also the key to the successful implementation of PCB copy board. The following is Shenzhen RayMing summary of more than a decade of PCB copy board experience, now provides you with several easy and effective methods to disassemble the circuit board for your reference.

A. Solder sucker tin disassembly method

The use of solder absorbers to disassemble the integrated block, which is a common professional method, the use of tools for ordinary suction, soldering soldering iron, the power of more than 35W. When disassembling the integrated block, as long as the heated dual-use soldering iron head on the pins of the integrated block to be disassembled, to be melted solder joint tin is sucked into the fine tin ware, all the pins of the solder sucked after the integrated block can be taken off.

Second, medical hollow pin disassembly method

Take a few medical hollow pins of 8 to 12. When the use of the needle is just the right set of internal warp integration block pins appropriate. Disassembly with a soldering iron to dissolve the pin solder, in time to use the pin set pin, then remove the soldering iron and rotate the pin, and so the solder solidification after pulling out the pin. So the pin is completely separated from the printed board. After all the pins are done once, the integrated block can be easily taken off.

Three, multi-strand copper wire suction tin removal method

It is the use of multi-strand copper core plastic wire, remove the plastic skin, use multi-strand copper core wire (can use short wire head). Before using the multi-stranded copper core wire on the rosin alcohol solution, to be hot soldering iron will be multi-stranded copper core wire into the integrated block pins heated, so that the tin solder on the pins will be adsorbed by the copper wire, suck on the part of the solder can be cut off, repeated several times on the pins can be sucked away all the solder. Conditions can also use the braided wire inside the shield. As long as the solder sucked, with tweezers or a small “a” screwdriver gently pry, the integrated block can be removed.

Four, soldering iron brush with disassembly method

The method is simple and easy, as long as there is a soldering iron and a small brush can be. When disassembling the integrated block, the soldering iron is first heated to reach the melting temperature of the solder on the pins, and then take the opportunity to sweep off the melted solder with a brush. In this way, the pins of the integrated block can be separated from the printed board. The method can be divided into pins or can be carried out separately. Finally, use pointed tweezers or small “a” screwdriver to pry down the integrated block.

Five, increase the solder melting demolition method

The method is a hassle-free method, as long as the integrated block to be disassembled on the pins and then increase some solder, so that the solder joints of each column of pins are connected, so as to facilitate heat transfer, easy to disassemble. When disassembly with a soldering iron each heated column of pins with pointed tweezers or small “a” screwdriver pry a pry, two columns of pins rotating heating, until removed. In general, each column of pins heated twice can be removed.

Thus, although the PCB copy process of disassembling the integrated circuit is easy to make mistakes, but as long as the step-by-step, according to the correct method of disassembly, you can ensure the complete disassembly of the integrated circuit, the successful completion of the PCB copy board to lay a solid foundation.

Of course, in the PCB copy process, in addition to the disassembly of integrated circuits, there are many details that need attention. Shenzhen RayMing has a professional PCB copy team, which has accumulated rich experience in the process of copying boards for more than ten years, and is sincere in solving problems and providing more new strength for the steady development of PCB copy boards in China.

How to choose the right board when PCB copy

PCB copy how to choose the right board, choose PCB board must be in the middle of meeting the design requirements and mass production and cost to strike a balance. Design requirements include both electrical and mechanical components. Usually in the design of very high-speed PCB board (greater than GHz frequency) when the material issues will be more important. For example, now commonly used FR-4 material, in a few GHz frequency dielectric loss (dielectric loss) will have a significant impact on signal attenuation, may not be suitable. In terms of electrical, we should pay attention to the dielectric constant (dielectricconstant) and dielectric loss in the designed frequency is suitable.

94HB: ordinary cardboard, not fire-resistant (the lowest grade material, die punching, can not do power supply board)
94V0: flame retardant cardboard (die-punched)
22F: single-sided half glass fiber board (die-punched)
CEM-1: single-sided fiberglass board (must be computer-drilled, can not be die-punched)
CEM-3: double-sided half glass fiber board (except double-sided cardboard belongs to the lowest material of double-sided board, simple double-sided board can use this material, cheaper than FR-4)

FR-4: double-sided glass fiber board

High Tg printed circuit board when the temperature rises to a certain threshold, the substrate will change from “glassy” to “rubbery”, the temperature at this time is called the glass transition temperature (Tg) of the board. In other words, Tg is the maximum temperature (℃) of the substrate to maintain rigidity. That is, ordinary PCB substrate materials at high temperatures, constantly produce softening, deformation, melting and other phenomena, but also in the mechanical and electrical properties of the sharp decline, which affects the service life of the product, the general Tg of the board for more than 130 ℃, high Tg is generally greater than 170 ℃, medium Tg about greater than 150 ℃; usually Tg ≥ 170 ℃ PCB printed board, called high Tg Printed board; substrate Tg improved, the heat resistance of the printed board, moisture resistance, chemical resistance, stability resistance and other characteristics will be increased and improved. the higher the TG value, the better the temperature resistance of the board, especially in the lead-free process, high Tg application more; high Tg refers to high heat resistance. With the leapfrog development of the electronics industry, especially the electronic products represented by the computer, to the development of high functionality, high multi-layer, the need for PCB substrate materials of higher heat resistance as a prerequisite. The emergence and development of high-density mounting technology represented by SMT and CMT make PCB in small aperture, fine line, thinning, more and more inseparable from the support of high heat resistance of the substrate.
So the general FR-4 and high Tg difference: the same at high temperatures, especially under the heat after moisture absorption, its material mechanical strength, dimensional stability, adhesion, water absorption, thermal decomposition, thermal expansion and other differences in various cases, high Tg products are obviously better than ordinary PCB substrate materials.
PCB sheet knowledge and standards currently used in large quantities in our country have the following types of copper-laminate, its characteristics are as follows: copper-laminate types, copper-laminate knowledge, there are various methods of classification of copper-clad foil board. Generally according to the different reinforcing materials of the board, can be divided into: paper-based, glass fiber cloth-based, composite base (CEM series), laminated multilayer board-based and special material-based (ceramic, metal core base, etc.) five categories. If classified according to the different resin adhesives used in the board, the common paper-based CCI. are: phenolic resin (XPc, XxxPC, FR-1, FR a 2, etc.), epoxy resin (FE a 3), polyester resin and other various types.

Common glass fiber cloth-based CCLs include epoxy resins (FR I 4, FR-5), which are the most widely used type of glass fiber cloth base today. There are also other speciality resins (with glass fiber cloth, polybase amide fiber, nonwoven fabric, etc. as added materials): bismaleimide modified triazine resin (BT), polyimide resin (PI), diphenyl ether resin (PPO), maleic anhydride imide – styrene resin (MS), polycyanate resin, polyolefin resins, etc. According to the classification of CCL flame retardant performance, it can be divided into two types of boards: flame retardant (UL94 a VO, UL94 a V1 level) and non-flame retardant (UL94 a HB level). In recent years, as more attention is paid to environmental issues, a new type of CCL without brominated substances has been introduced in the flame retardant CCL, which can be called “green flame retardant CCL”.

With the rapid development of electronic products technology, there are higher performance requirements for cCL. Therefore, the performance classification of CCL is divided into general performance CCL, low dielectric constant CCL, high heat resistance CCL (generally the L of the board is above 150℃), low thermal expansion coefficient CCL (generally used in packaging substrate) and other types. With the development and continuous progress of electronic technology, new requirements for printed board substrate materials are constantly put forward, thus, promoting the continuous development of copper-clad board standards.