What are the problems of solder paste turning yellow or black? Let's briefly discuss.

Generally, we useSolder pasteWhen soldering electronic circuit boards, sometimes some problems may occur, such as false soldering, solder balls, blackening, yellowing, etc. How do these problems arise? Today, the solder paste manufacturer will introduce to you the problems of yellowing and blackening of solder paste after soldering.

I. Causes and Countermeasures of Yellowing after Solder Paste Soldering:

1When solder shows color, it is generally closely related to the temperature. When the temperature of the solder is too high, the surface of the solder liquid will turn yellow. At this point, the temperature of the tin furnace needs to be adjusted to an appropriate operating temperature. 

2There is too much rosin in the solder paste. Rosin is usually yellow or brown. When the rosin content in the solder paste is too high, the soldered electronic circuit boards will appear yellow. It is recommended to choose solder paste with a low rosin content.

Ii. Reasons and Countermeasures for Solder explosion during solder paste Soldering and Solder beads after Soldering:

whenPCBThe board surface is damp due to special circumstancesPCBIf the humidity on the board surface is too high, it is prone to tin explosion and the formation of tin beads when in contact with high-temperature solder solution during soldering. It is recommended to pay attention to moisture-proofing andPCBThere is a procedure for drying the board part during the manufacturing process of the board. 

Iii. Blackening of solder paste after soldering is a common problem in the use of solder paste:

Some solder paste manufacturers simply attribute it to insufficient temperature in the solder paste reflow soldering. In fact, the blackening of solder paste is not mostly caused by insufficient temperature; rather, it is due to certain factorsSMTUsed by the manufacturer4The temperature zone reflow soldering equipment is too high and the heating rate is too fast, which causes the solvent in the solder paste to evaporate too quickly and the tin powder in the solder paste to oxidize prematurely, resulting in the soldered solder joints turning gray or black.

Another reason is that some solder paste manufacturers use oxidized tin powder as raw materials. It is suggestedSMTWhen choosing a solder paste factory, manufacturers should not overly pursue low prices, as solder paste with oxidized solder powder cannot be used and various soldering problems such as false soldering and component dropping may occur.

That's all for today's solder paste knowledge. If you want to learn more about soldering, please continue to follow JJY Solder Paste Factory and leave a message online to interact with us!