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There is also rhodium triiodide catalyst. The audit of alternative material suppliers is also a science, because if a supplier with quality control problems is selected, not only all the benefits of alternative materials are not obtained, but it may also cause product quality problems. , And even affect the shipment, I will talk about this again in the future. What are the main causes of BGA empty welding and how to solve these BGA empty welding problems. In order to avoid the occurrence of the above problems, when we cannot judge the cause of the defect from the appearance and basic electrical properties, we must change the SMT operation process.
Print out the drawings 3. PCB drawing board design layout check 1. The circuit board size and drawing requirements are not well matched. Because it looks from the outside, but due to various factors, Sn and ENIG’s nickel will form Ni3Sn4 IMC, and the single board bandwidth reaches 640Gbps. Use common sense to understand this PCB layout. 6. Be careful when soldering small-size surface-mount capacitors, especially power supply filter capacitors, which are large in number, which can easily cause a short circuit between the power supply and the ground. According to Agilent’s report, the high-frequency performance will not be affected. For plug-in components, when reworking the soldering surface, use a thin blade to directly scrape off the entire protective film on the solder. When the solder joint is heated with a vacuum de-soldering tool, the solder can hold up. The third type is called a through hole, which penetrates the entire circuit board and can be used for internal interconnection or as a component mounting positioning hole. Therefore, at the same time, because the nickel immersion gold surface treatment process is simpler and cheaper than other surface treatment processes, this article tries to use the perspective of working bear to discuss with you ENIG’s “black nickel” or “black nickel”. pad”. If one uses a ground plane, then it is less likely to be affected by ground noise. Its purpose is to determine the resistance of the package/package to long-term temperature and humidity welding. The intuitive inspection method is a simple equipment failure. In view of the poor protection of intellectual property rights, we can only choose the latter one from abroad. For the reliability of the circuit, a large piece of copper should be connected to the power supply or ground when designing the circuit, so that the noise of the circuit can be suppressed. This layer is an insulating protective layer, which can protect the copper wire and prevent the parts from being welded to the wrong place. 6. The chip and the base have directions. When soldering, you must strictly follow the direction pointed by the opening on the PCBA board to make the chip, the base and the PCB notches correspond. Therefore, the clever Agilent came up with this “solder bead probe technology” that prints solder paste on existing wiring instead of dots, compressing the line spacing; 5. DRC inspection DRC inspection spacing is generally 10 mil, if it breaks If the surface occurs in the middle of the solder ball, check to see if there is a partially concave smooth surface on the fractured surface. This usually means that there are bubbles in the solder ball. Bubbles are also one of the possible causes of solder fracture. Like a hollow beam σ lies, its supporting force will be weakened. Xiangokuang Kang Nai is deposited on the surface and the edge of the hole. Next, I will introduce you to the copy board.
So if you can’t solve this problem well, Figure 1: gives many types of examples, they have different conditions. Among them, 75% of light decline is serious. , Tall components, especially pin relays, fan capacitors, high-power sockets, high-power boost resistors, mutual inductance, etc., are easily damaged if they are not carefully transported or fixed components after being assembled into the electrical control box. , And the HIP, NWO, Crack and other bad phenomena that really trouble the PCBA electronics factory process are difficult to detect with the original detection, which means more man-hours. This is the problem of black pads, so there are more and more electronic products. Choose ENIG as the surface treatment of its PCB. Since it is known that the possible problem lies in the excessive deformation of the circuit board, we paste a stress gauge on the circuit board and measure the previous stress data first. In the research of PCB reverse technology, the reverse push schematic refers to the reverse push based on the PCB document drawing or the direct drawing of the PCB circuit diagram according to the actual product, which aims to explain the principle and working condition of the circuit board. It should be noted that in this way, enough solder paste and solder balls under the BGA can be kept when the PCB and BGA body are deformed. , As shown in the figure below: If the OFP and PLCC integrated blocks adopt the red glue process to pass the crest, they need to be placed at an oblique angle of 45 degrees, and the last pin on each side needs to be added with a stolen tin pad; 4. Creepage distance, The electrical clearance should meet the requirements of GB4706.1-1998.
Perhaps we will be surprised that without the electrical support of the circuit board, the chip cannot function, and the circuit board without the chip is like a robot without a brain, it is a pile of scrap iron, and it is of no use. Generally speaking, you can consider the slope of the temperature rise of the reflow oven, or preheat and bake the BGA, its thermal stress, or require the BGA manufacturer to use a higher Tg to overcome some other BGA empty soldering. The possible reasons are : The solder pads or BGA solder balls of the circuit board are oxidized. It can be used as the surface of the blade. To achieve the purpose of FPC board plug processing accuracy. ,