What are the causes and solutions for insufficient melting of solder paste in SMT processing?

SMTIn actual production and processing, there are many possibilities for incomplete melting of solder paste. Below, Shenzhen JJY Solder Paste Factory will briefly introduce to you the common causes and solutions for incomplete melting of solder paste:

1When all or most of the solder joints are insufficiently melted after surface mount technology (SMT) processing, it may be due to the low reflow soldering temperature or the short reflow time.

Solution: Adjust the temperature curve. Generally, the peak temperature is set higher than the melting point of the solder paste30℃-40℃The reflux time is30~60s.

2When welding large-sized materialsPCBAIf the solder paste on both sides does not melt sufficiently, it might be due to uneven temperature inside the reflow oven. This situation usually occurs in reflow ovens where the furnace body is relatively narrow and the heat preservation effect is not good.

Solution: It can be solved by appropriately increasing the peak temperature or extending the reflux time, and inSMTDuring the surface mount technology (SMT) processing, try to minimizePCBAPlace it in the middle of the welding furnace for reflow soldering.

3In batchSMTDuring processing, the situation where solder paste is not fully melted always occurs at some fixed locations, such as around large solder joints and large components, or at the positions of components with large heat capacity on the back. It is very likely caused by excessive heat absorption leading to blocked heat conduction.

Solution: During the design process, large components can be placed on the same side as much as possible or arranged alternately. Additionally, the peak temperature can be appropriately increased or the reflow time extended.

4The quality issue of solder paste isSMTIf the oxygen content of the metal powder in the solder paste used in surface mount technology (SMT) processing is high, the performance of the solder paste may be poor. Or if the solder paste is taken out of the refrigerator and used directly without warming up, in this case, due to the temperature of the solder paste being lower than the room temperature, water vapor condensation occurs, that is, the solder paste absorbs moisture from the air, and after stirring, the water vapor mixes in the solder paste, or recycled and expired solder paste is used.

Solution:SMTThe processing plant should not use inferior solder paste in the production and processing, and should formulate a complete management system for the use of solder paste.

16For many years, JJY has been dedicated to the research and development, production and sales of solder paste, providing customers with a complete set of electronic soldering solutions. If you want to learn more about solder paste, please keep following JJY Solder Paste Manufacturer and leave a message online to interact with us.