What are the factors that cause insufficient gloss of solder joints in solder paste surface mount processing?

Whether the welding point is bright is also a relatively important parameter in the welding process. Whether the solder joints are bright affects the appearance of the product. Nowadays, many product users have certain requirements for the appearance of products. It is suggested that we pay attention to the brightness of the solder joints when completing the processing of solder paste and welding. However, during the process of solder paste surface mount processing and soldering, it cannot be guaranteed that the brightness of each solder joint will meet the requirements, which directly affects Solder pasteWhat are the factors that cause insufficient gloss of solder joints in surface mount technology (SMT) processing? Today, the solder paste manufacturer will take you to understand and analyze:

The reasons that directly affect the brightness limit of solder joints are no more than the following aspects, namely the operation process reasons during production and the difficulties of welding materials.

I. Operation procedures during the production process:

1When the working temperature inside the furnace is far from sufficient during production or the temperature inside the furnace rises, it is possible that the brightness of the solder joints is far from sufficient.

2If the reflux time is too long or the preheating working temperature is too low, it can also cause the solder joint to discolor. Nitrogen protection can be added.

3.Whether the cooling is completed in time or is relatively slow, there will also be a lack of brightness. The brightness of the solder joint can also be solved by accelerating the cooling.

Ii. Difficulties in Welding Materials:

1The solder joints of tin-lead alloy solder paste will also be brighter than those of lead-free solder paste. The surface of the solder joints of lead-free solder paste will be relatively rough. Once lead-free solder paste is needed, it can be modified to lead-free solder paste containing silver, which can also effectively improve the gloss of the solder joints.

2The solder paste contains silver surfactants. We have various market demands for the brightness of solder joints. The vast majority of people welcome solder joints to be bright, but some people think that the opposite brightness seriously affects the routine inspection by visual inspection. Therefore, some solder pastes make full use of matting agents. It is recommended that when purchasing solder paste, everyone should pay close attention to the flux material formula of the solder paste.

3The degree of oxidation of the solder paste is too high. After removing the solder paste, it is recommended to24Make full use of it within hours and it must be stored before3-5℃In the environment.