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  • Flexibility and reliability of flexible pcb
    Flexibility and reliability of flexible pcb
    • 2019-11-19

    At present, FPC has four types: single-sided, double-sided, multi-layer flexible board and rigid flex pcb. 1. Single-sided flexible pcb board is the lowest cost, when the board is not required for electrical performance. For single-sided wiring, a single-sided flexible board should be used. It has a chemically etched conductive pattern, and the conductive pattern layer on the surface of the flexible insulating substrate is a rolled copper foil. The insulating substrate may be polyimide, polyethylene terephthalate, aramid fiber ester and polyvinyl chloride. 2. Double-sided flexible board is a conductive pattern made by etching each layer on both sides of the insulating base film. The metallized holes connect the patterns on both sides of the insulating material to form a conductive path to meet the design and use functions of the flexibility. The cover film protects the single and double-sided wires and indicates where the components are placed. 3. Multi-layer flexible board is a single-sided or double-sided flexible circuit of 3 or more layers laminated together, and a metallized hole is formed through a drill collar L and electroplating to form a conductive path between different layers. This eliminates the need for complex welding processes. Multilayer circuits have tremendous functional differences in terms of higher reliability, better thermal conductivity, and more convenient assembly performance. When designing the layout, the interaction between assembly size, number of layers, and flexibility should be considered. 4. Conventional rigid flex pcb are composed of rigid and flexible substrates that are selectively laminated together. The structure is tight, and the metallized forms an electrically conductive connection. If a printed board has components on both the front and back sides, a rigid flexible board is a good choice. But if all the components are on one side, it is more economical to use a double-sided flexible board and laminate a layer of FR4 reinforcement on the back. 5. The flexible circuit of the hybrid structure is a multilayer board, and the conductive layer is composed of different metals. An 8-layer board uses FR-4 as the inner layer medium, using polyimide as the outer layer medium, and the leads are extended from three different directions of the main board, each of which is made of a different metal. Constantan, copper and gold are used as separate leads. This kind of hybrid structure is mostly used in the relationship between electrical signal conversion and heat conversion and the low temperature condition with relatively strict electrical performance, which is the only feasible solution. It can be evaluated by the convenience and total cost of the interconnect design to achieve the best performance-price ratio.

  • High reliability and military PCB material selection and processing - how to deal with polyimide
    High reliability and military PCB material selection and processing - how to deal with polyimide
    • 2019-11-19

    Due to its high glass transition temperature and high decomposition temperature, polyimide resin has high temperature resistance, and the fabricated PCB also has high reliability and high temperature resistance. The article starts with the analysis of resin, introduces the characteristics of polyimide PCB, and introduces the process points of processing polyimide PCB. The main parameters are compared as shown in the table below. From Table 1, it is not difficult to see that polyimide resin has the following main features: • Excellent space radiation resistance, used in space, without any physical and chemical changes caused by space radiation, thus ensuring the stability of electrical performance. • High Tg for good PTH and pad reliability. • High Td, making it suitable for any high temperature environment. • Stable dielectric constant for impedance control applications.   Application characteristics   1. High reliability It can be seen from the molecular structure diagram that polyimide has more benzene ring structure than epoxy resin molecular structure, its thermal stability is very high, and it takes a very high temperature to bond molecules and molecules. It breaks, so its glass transition temperature is very high (250 ° C). Figure 1 shows the Z-axis expansion of different materials at different temperatures. The higher the Tg, the smaller the Z-axis expansion when the PCB is heated (either during the process or in the application). This results in a reduction in the stress of the vias, thereby reducing hidden PTH defects and having higher PCB reliability. The higher the Tg, the lower the likelihood that the pads and lines will fall off the PCB surface during rework. This is why almost all military PCBs use polyimide because reliability is very important in these areas. The higher the Tg, the lower the possibility of resin shedding due to the difference in thermal expansion coefficient between the resin and the glass.   Also from the molecular structure, we can see that most of the bonds in PI are double bonds. To break the atomic bonds in the molecule and cleave it, a higher temperature is required, and its thermal decomposition temperature is also above 360 °C. . High thermal decomposition temperatures allow the material to withstand high temperature soldering (eg, lead-free soldering, etc.). 2. Long-term working temperature The long-term operating temperature is a reference value in the UL standard, which reduces the mechanical and electrical properties of the material by 50% as a reference point. In general, the comprehensive reliability of polyimide materials is much higher than other resin materials. Kevin T. Knadle and Virendra R. Jadhav (Endicott Interconnect Technologies, Inc) in 2005 component reliability test and PCB plating The results of the hole reliability are shown in Fig. 2. From Figure 2 we can see that if the FR-4 is continuously heated from 23 ° C to 150 ° C, 1000 cycles, the PCB will fail. Polyimide m...

  • What are the bad factors for soldering the circuit board caused by quick turn pcb of HDI board?
    What are the bad factors for soldering the circuit board caused by quick turn pcb of HDI board?
    • 2019-11-18

    HDI PCB resin plug hole process includes drilling, plating, plugging, baking, grinding, after drilling, the hole is plated, then the resin is baked, and finally the grinding is smoothed and smoothed. Because the resin does not contain copper, it needs to be turned into a PAD again. This process is done before the original PCB drilling process, that is, the hole of the plug hole is processed first, and then the other holes are drilled. According to the original normal process. What are the bad factors for soldering the circuit board caused by quick turn pcb of HDI board? 1. Storage time - For the storage of PCB board, it is necessary to use the warehouse with suitable dry humidity. The PCB board finished light board is vacuum-packed. If the vacuum packaging is damaged, the length of the tin-plated board is theoretically one month, weldability. Good PCB board for 2 days (recommended to store the PCB for more than 30 days, return to the PCB manufacturer, use special potions for cleaning and baking, the baking time is 60 minutes, the parameter is 150%) 2, the production process - after the completion of the tin-plating process on the PCB board, the operators are required to wear anti-static gloves, because the finger dry liquid or stain directly touches the surface of the board, which will lead to surface oxidation, if it causes bad products, and irregular In the case of the presentation, it is difficult to demonstrate the test and the tin-on-life insurance (Therefore, circuit board manufacturers are very strict with the production environment and technical personnel.). 3. Welding caused by warpage - PCB board components will warp during soldering. If the temperature of the lower part of the board is different, stress deformation may occur and defects such as solder joints and short circuits may occur. Relatively heavy PCB lines The board itself will produce warpage, and the distance of the general PBGA device on the printed circuit board is about 0.5mm. 4, material procurement - a small number of PCB manufacturers may have compression costs, recycling tin or unstable sources of supply (in the choice of circuit board manufacturers, it is recommended that customers carefully choose a very low price PCB supplier). 5, the maintenance of the tin furnace - on the surface of the circuit board where the soldering is not dry, the characters are not solid, the surface of the circuit board will be peeled off, the soldering of the tin furnace, the high temperature evaporation causes the surface to be attached, because the tin furnace is not cleaned up on time, so On-time maintenance of the tin furnace is very important.

  • Quick turn pcb for hdi pcb and fpc pcb
    Quick turn pcb for hdi pcb and fpc pcb
    • 2019-11-16

    Quick made the HDI PCB prototype. HDI PCB , FPC flexible pcb  have good heat dissipation and solderability, and is easy to install and low in overall cost. The combination of rigid flex pcb design also compensates for the capacity of the flexible substrate in terms of component carrying capacity. Slightly insufficient. Flexible printed wiring boards are available in single-sided, double-sided and multi-layer boards. The substrate used is mainly a polyimide copper clad laminate. The material has high heat resistance and good dimensional stability, and is formed into a final product by pressing with a cover film having both mechanical protection and good electrical insulation properties. The surface and inner conductors of the double-sided, multi-layer printed wiring board are electrically connected to each other through metallization. The functions of flexible circuit boards can be divided into four types: Lead Line, Printed Circuit, Connector, and Integration of Function. The purpose is to cover computers and computer peripherals. Auxiliary systems, consumer livelihood appliances and automobiles.   The shorter the lead between the pins of the high-frequency circuit device, the better. HDI circuit board high frequency circuit device device between the pin layers alternately less as possible. The less the interlayer crossing of the lead wire, the better. The less the via Via used in the component connection process, the better. It is measured that a via hole can bring about a distributed capacitance of about 0.5 pF, and the number of via holes can be significantly increased. HDI circuit board prototype multi-layer board circuit connection is through buried hole and blind hole technology, motherboard and display card mostly use 4 layers of PCB board, and some use 6, 8, or even 10 layers of PCB board. To see how many layers are on the PCB, you can identify them by observing the vias, because the 4 layers used on the motherboard and the display card are the 1st and 4th layers, and the other layers have other uses (ground). And power). Therefore, like the double-layer board, the guide hole will penetrate the PCB board. If some of the vias appear on the front side of the PCB, but are not found on the reverse side, then it must be a 6/8 layer. If the same guide hole can be found on both the front and back of the PCB board, it is naturally a 4-layer board.

  • What is the key point for multilayer PCB board design?
    What is the key point for multilayer PCB board design?
    • 2019-11-15

    PCB multilayer board design recommendations and examples (4, 6, 8, 10, 12-layer board) illustrate PCB design requirements: A. Surface and surface are complete ground planes (shield); B. No adjacent parallel wiring layers; C All signal layers are as close as possible to the ground plane; D. The key signals are adjacent to the ground plane and do not span the partition. 4-layer board Option 1: There is a ground plane under the component surface, and the key signal is preferentially placed on the TOP layer. As for the layer thickness setting, there are the following suggestions: 1: Meet the impedance control 2: The core board (GND to POWER) should not be too thick to reduce, ground The distributed impedance of the plane; the decoupling effect of the power plane is guaranteed. Option 2: Defect 1: Power supply and ground are too far apart, power plane impedance is too large 2: Power supply and ground plane are extremely incomplete due to component pads, etc. 3: Signal impedance is discontinuous due to incomplete reference surface Option 3: Similar to scenario 1, for the case where the main device is in the BOTTOM layout or the critical signal is underlying. 6-layer board Solution 3: One signal layer is reduced, and one internal power layer is added. Although the available wiring level is reduced, the PCB design solution solves the defects common to the first and second solutions. Advantages: 1: The power and ground layers are tightly coupled. 2: Each signal layer is directly adjacent to the inner layer, and is effectively isolated from other signal layers, and crosstalk is less likely to occur. 3: Siganl_2 (Inner_2) and two internal layers GND (Inner_1) and POWER (Inner_3) are adjacent to each other and can be used to transmit high-speed signals. The two inner layers can effectively shield the external interference to the Siganl_2 (Inner_2) layer and the interference of the Siganl_2 (Inner_2) to the outside world. Solution 1: Four layers of signal layers and two layers of internal power/ground layers are used, with more signal layers, which facilitates the wiring work. Defect: 1: The power and ground layers are separated far apart and are not fully coupled. 2: The signal layer Siganl_2 (Inner_2) and Siganl_3 (Inner_3) are directly adjacent, and the signal isolation is not good, and crosstalk is likely to occur. 8-layer board 10-layer board 12-layer board Personal summary: 1. The key signal layer of the PCB design should be adjacent to the ground. GND should be adjacent to the power to reduce the power plane impedance. 2. Do not adjacent between signal layers, increase the isolation between signals to avoid crosstalk. 3. The signal layer should be adjacent to the ground plane as much as possible, and no parallel wiring between adjacent layers. 4. For the transmission line, the top layer is analyzed by the microstrip line model, and the inner signal layer is modeled by the strip line. The signal layers on both sides of the 6 layer/10 layer / 14 layer / ...

  • Ten difficulties in PCB prototype design
    Ten difficulties in PCB prototype design
    • 2019-11-14

    First, the definition of PCB prototype is not clear The single-panel design is in the TOP layer. If you do not explain the positive and negative, you may make the board and install the device without soldering. Second, PCB prototype large area copper foil is too close to the outer frame Large-area copper foil should be at least 0.2mm or more from the outer frame, because it is easy to cause the copper foil to rise and cause the solder resist to fall off when milling to the copper foil. Third, the PCB prototype fills the pad to draw the pad Draw a pad with a pad to pass the DRC check when designing the line, but it is not suitable for processing. Therefore, the pad cannot directly generate solder resist data. When the solder resist is applied, the pad area will be covered by the solder resist, resulting in the device. Welding is difficult. Fourth, the quick turn pcb electric ground is the flower pad and the connection Because the design is a flower pad mode power supply, the ground layer is opposite to the actual printed board image. All connections are isolated lines. Care should be taken when drawing several sets of power supplies or several ground isolation lines. The power supply is short-circuited and cannot cause the connection area to be blocked. Five, PCB prototype characters are placed indiscriminately The character cover pad SMD soldering piece brings inconvenience to the printed board on-off test and component soldering. Character design is too small, making screen printing difficult, too large will make characters overlap each other, difficult to distinguish. Sixth, PCB prototype surface mount device pads are too short For the continuity test, for a too dense surface mount device, the spacing between the two legs is quite small, and the pads are also relatively thin. The test pins must be placed up and down, such as the pad design is too short, although not Affects device mounting, but causes the test pin to be misplaced. Seven, single-sided pad aperture setting Single-sided pads are generally not drilled. If the holes are to be marked, the aperture should be designed to be zero. If a numerical value is designed, when the drilling data is generated, the hole coordinates appear at this position, and a problem occurs. Single-sided pads such as drilled holes should be specially marked. Eight, PCB prototype pad overlap In the PCB prototype drilling process, the drill bit is broken due to multiple drilling in one place, resulting in damage to the hole. The two holes in the multi-layer board overlap, and the negative film is formed as a spacer disk, which causes scrapping. Nine, the PCB prototype design has too many filling blocks or the filling block is filled with very thin lines. There is a loss of the generated light data, and the light data is not complete. Because the filling block is drawn by lines one by one during the processing of the light drawing data, the amount of light drawing data is quite large, which increases the difficult...

  • Five key factors in PCB design
    Five key factors in PCB design
    • 2019-11-13

    The PCB board is the basic electronic component of all electronic circuit design, and as the main support, it carries all the components that make up the circuit. The role of the PCB is not only to combine the scattered components, but also to ensure the regularity of the PCB design, and to avoid the confusion and error caused by the manual cable and wiring. This paper gives a detailed introduction to the five key design points of the PCB circuit board in the power supply design. 1, PCB design should have a reasonable direction Such as input / output, AC / DC, strong / weak signals, high frequency / low frequency, high pressure / low voltage. Their orientation should be linear (or separate) and should not be intertwined. Its purpose is to prevent mutual interference. The best direction is in a straight line, but it is generally difficult to achieve. The most unfavorable trend is the ring. Fortunately, isolation can be improved. For DC, small signal, low voltage PCB design requirements can be lower. So "reasonable" is relative. 2, PCB design choose a good grounding point: the grounding point is often the most important Little grounding point I don't know how many engineers and technicians have discussed it, which shows its importance. In general, it is required to share the ground. For example, multiple ground wires of the forward amplifier should be connected and then connected to the trunk line. In reality, it is difficult to do it completely because of various restrictions, but you should try to follow it. This problem is quite flexible in practice. Everyone has their own set of solutions. It can be easily understood if it can be explained for a specific board. 3, PCB design rationally arrange power supply filter / decoupling capacitor Generally, only a few power supply filtering/decoupling capacitors are drawn in the schematic diagram, but it is not indicated where they should be connected. In fact, these capacitors are set for switching devices (gates) or other components that require filtering/decoupling. These capacitors should be placed as close as possible to these components, and it would be ineffective if they are too far apart. Interestingly, the grounding point problem is less noticeable when the power supply filtering/decoupling capacitors are properly arranged. 4, PCB design line diameter has the required size of buried hole through hole. Conditions that have wide lines should never be made fine; high-voltage and high-frequency lines should be smooth, no sharp chamfers, and corners should not be used. The ground wire should be as wide as possible, and it is best to use a large area of copper, which has a considerable improvement on the grounding point problem. The pad or via hole size is too small, or the pad size is not properly matched to the hole size. The former is not good for manual drilling, and the latter is not good for CNC drilling. It is easy to drill the pad into a "c" shape and then drill the pad. The wire is too thin, ...

  • Advantages of HDI PCB and the market for hdi pcb
    Advantages of HDI PCB and the market for hdi pcb
    • 2019-11-12

    HDI PCB, because the hole can be used in the middle, can reduce the redundant routing of the PCB board, reduce the number of layers of the board and thus reduce the cost of the board: when the density of the PCB increases beyond eight layers, Use HDI PCB To manufacture, the cost will be lower than the traditional complex pressing process. Increase line density: interconnection of traditional boards and parts     HDI PCB facilitates the use of advanced packaging technology. Better electrical performance and signal correctness. Better reliability. Improves thermal properties. Improves RF interference/electromagnetic interference/electrostatic discharge (RFI/EMI/ESD). Increases PCB design efficiency.

  • Double 11th  Global Carnival shopping festival
    Double 11th Global Carnival shopping festival
    • 2019-11-05

    Double 11th in China just like Black Friday in USA, there have something different: Double 11th Carnival shopping festival not only in China, now is more and more countries join in. For the special days, Fast turn PCB INT’L Company will have big return for all the customers, Including old and new customers. Our main products: Rigid PCB, Flexible PCB, Rigid-flex PCB, aluminum pcb, hdi pcb, multilayer pcb and etc. We can offer PCB design services and PCB layout services. The Activity rules as below: Activity time: 7th - 11th Nov.2019 Activities: During 7th-11th Nov.2019, All of old customers repeat the first order will be enjoy 5% discount, New orders will be enjoy 10% discount. All of the new customers give us first orders will be enjoy 15% discount, We will be subject to the Bank receipt. During that time introduce new customer and give us orders will be have $150 award. Cut-off time is 11th.Nov 2019.  Only one chance in a year, Don’t miss it.

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