In smt patch processing, soldering is an important link, which is related to the performance and appearance of the circuit board. In actual production and processing, poor soldering may occur due to some reasons, such as common solder joints. Not full, will directly affect the quality of smt patch processing. So what is the reason why the tin is not full on smt chip processing? The following is an introduction to Shenzhen professional patch manufacturer VIASION Electronic Technology Co., Ltd.The main reasons for the insufficient tin on the solder joints of smt patch processing:
1. The wetting performance of the flux in the solder paste is not good, and it cannot meet the requirements of good tinning; 2. The activity of the flux in the solder paste is not enough to complete the removal of oxides from PCB pads or SMD soldering positions; 3. The flux expansion rate in the solder paste is too high and voids are easy to appear; 4. The PCB pad or SMD soldering position has serious oxidation, which affects the tinning effect; 5. Insufficient amount of solder paste at the solder joints leads to insufficient soldering and vacancies; 6. If there is insufficient tin on some solder joints, the reason may be that the solder paste has not been fully stirred before use, and the flux and tin powder cannot be fully fused; 7. The preheating time is too long or the preheating temperature is too high during reflow soldering, which causes the flux activity in the solder paste to fail.
At present, most SMT chip processing manufacturers use advanced testing equipment to monitor the quality of the production process. During the reflow soldering process, AOI inspection equipment is generally used for quality control. Due to the high cost of automatic parameter adjustment and feedback in the quality control process, manual settings are required. In this case, it is even more necessary for electronic patch companies to formulate some practical and effective specifications and systems, strictly implement the established specifications, and achieve process stability through manual monitoring. In the formulation of quality control specifications for electronic patch prices, the response ability of operators and the control of equipment are very important.