Honglian Circuit Technology Department (He Jialiang) has summarized some opinions about poor tin on the tin surface of the circuit board. You can refer to it and hope to help you. The factors that cause poor PCB soldering mainly come from two aspects: the circuit board factory and the placement factory.

1. Storage environment and transportation: This is the link between the circuit board factory and the placement factory. Generally, there is little inventory of circuit boards, but the general inventory requires the storage environment to be dry and humid, complete in packaging, and as light as possible during transportation. Handle with care. Do not allow the damaged vacuum package to be stored for a long time. The theoretical storage time of the spray tin board is one month, but the best soldering time is within 48 hours. If the storage time exceeds one month, it is recommended to return to the circuit board factory for special use. The potion is cleaned and baked. Baking parameters 150°, 1 hour

2. The operation is not in accordance with the operating specifications at the time of shipment: the circuit industry is a workshop environment, and the staff standard operation requirements are extremely strict, especially the chemical reaction environment is required in the circuit board production process, so no impurities are allowed to penetrate. After the board spraying process is completed, the subsequent series of operations require employees to wear anti-static gloves, because finger sweat or stains directly touch the surface, which will cause surface oxidation. If it causes defects, it is extremely difficult to find, and it is irregular. Test And the Shanghai tin experiment is hard to show.

3. Welding defects caused by warpage: circuit boards and components warp during the welding process, and defects such as virtual welding and short circuit due to stress deformation. Warpage is often caused by temperature imbalance between the upper and lower parts of the circuit board. For large PCBs, warping will also occur due to the drop of the board's own weight. The ordinary PBGA device is about 0.5mm away from the printed circuit board. If the device on the circuit board is large, the solder joint will be under stress for a long time as the circuit board cools down and the solder joint will be under stress. If the device is raised by 0.1mm, it will be enough to cause For special products, you can request the yin and yang jointing of the circuit board factory to reduce warpage, or adopt the appropriate size of the imposition as much as possible, and it should not be too large or too small.

:4. The source of tin for incoming materials: For material procurement, some circuit board factories blindly seek to reduce costs. When using tin sprayed raw tin, the procurement industry recycles tin, or sources of unstable content, generally the unit price is extremely low Circuit board factories may have such a risk, and it is recommended that you choose suppliers carefully.

5. The tin furnace used for spraying tin is not cleaned up on time: the on-time maintenance of the tin furnace is very important, because the tin spraying is a vertical cycle process, the circuit board surface will be under strong pressure, for those solder masks that are not dry and the characters are not strong The board will be impacted and fall off, deposited in the furnace, and evaporated at high temperature. If it is not cleaned for too long, it will cause surface adhesion.

Through the above simple understanding, do you have some insights on the poor tin surface of the circuit board? Shenzhen Honglian Circuit Co., Ltd. has been focusing on the R&D and production of high-precision multilayer circuit boards, single- and double-sided circuit boards, and special circuit boards for more than ten years. It has national certification and is a high-tech company integrating R&D, production and sales. Technology companies, if you are interested in our PCB circuit boards, please contact us: 0755-81720355.