What are the main factors affecting the quality of solder paste in SMT assembly?

inSMTIn the processing and production of surface mount technology (SMT),Solder pasteThe quality is of great significance and can directly affect the entire processSMTThe quality of the patch, high-quality solder can lead to high-quality soldering. Below, JJY solder Paste Manufacturer will give you a brief introduction to the impactSMTThe main factors affecting the quality of solder paste in surface mount technology (SMT)

1Viscosity

Viscosity is an important factor in the performance of solder paste. If the viscosity is too high, the solder paste is not easy to pass through the openings of the template. If the viscosity is too low, it is prone to flow and edge collapse.

2Stickiness

The viscosity of the solder paste is insufficient. The direct consequence is that the solder paste cannot fully fill the holes in the template, resulting in an insufficient amount of solder paste deposition. If the viscosity of the solder paste is too high, it will stick to the wall of the template hole and cannot be completely missed on the solder pad.

3The uniformity and size of the particles

The shape, diameter size and uniformity of solder particles in solder paste also affect its printing performance. The diameter of the general solder particles is approximately one fifth of the opening size of the template, that is, following the three-ball and five-ball law, for fine spacing0.5mmFor the solder pads, the opening size of the template is0.25mmThe maximum diameter of its solder particles shall not exceed0.05mmOtherwise, it is easy to cause blockage during printing.

4Metal content and thixotropic index

The content of metals in the solder paste determinesSMTThe thickness of the solder after surface mount soldering. With the increase of the percentage content of the metal, the thickness of the solder also increases. However, at a given viscosity, with the increase of the metal content, the tendency of solder bridging also increases accordingly. Thixotropic agents are used to endow solder paste with good thixotropy, that is, under the specified shear force and temperature environment, the viscosity can drop sharply, enabling the solder paste to smoothly open the template and have good demolding performance. However, after the shear force is removed, it can recover and thus ensure the high consistency of the solder paste. There is no doubt that the printing performance of the solder paste is largely determined by the thixotropic index of the solder paste itself.

The above is about the influenceSMTSome relevant introductions to the main factors of solder paste quality in surface mount technology. If you need to know more about the products, please feel free to consult JJY Solder Paste Factory and leave a message online to interact with us.