How to solve the problem that the PCB board has solder balls?
2024-03-04
In the process of PCBA processing, due to technical and manual operation factors, occasional solder beads and solder dross residues will inevitably appear on the PCBA board, which brings great hidden dangers to the use of products. Due to the loosening of solder beads and tin residues in an uncertain environment, a short circuit in the PCBA board can be formed, which can lead to product failure. The point is, this possibility is likely to occur during the product lifecycle, putting pressure on customers to sell.
The reason for the production of tin beads and solder dross in PCBA processing
1. Too much tin on the SMD pads. During the reflow soldering process, the molten tin extrudes the corresponding tin beads.
2. When the PCB board or component is exposed to moisture, the water will break during the reflow soldering process, and the spatter will spread to the surface of the board;
3. During the post-soldering operation of the DIP insert, when the tin is added manually and the tin is hoisted, the solder beads splashed from the soldering iron tip will fall onto the PCBA board;
4. Other unknown reasons.
Measures to reduce PCBA processing of solder beads and solder dross
1. Pay attention to the production of stencil, it is necessary to adjust the opening size appropriately according to the specific component layout of the PCBA board to control the printing amount of solder paste. This is especially true for some foot or panel components that are densely populated.
2. It is recommended to take a strict baking action on the bare PCB board with BGA, QFN and dense foot components on the board to ensure that the moisture on the upper surface of the solder board is removed, solderability is maximized and solder bead generation is eliminated.
3. The PCBA processing plant will inevitably introduce the manual welder position, which requires strict control of the solder swing operation in the management. Arrange a dedicated storage box, clean the workbench in time, and the soldering and pulling quality control center should conduct a visual inspection of the SMD components around the hand-soldered components, focusing on whether the solder joints of the SMD components have been accidentally touched and dissolved or dissolved. Solder beads and tin residues are scattered between the pins of the component.
The PCBA board is a relatively complex product component, which is very sensitive to conductive objects and ESD static electricity. In the PCBA process, the plant management personnel need to improve the management level (IPC-A-610E Class II is recommended), enhance the quality awareness of the operators and quality team, and implement it from both the process control and ideological aspects, so as to minimize the generation of tin beads and tin residues on the PCBA board.
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