The reflow soldering manufacturer Chengyuan found in the long-term production and manufacturing that the main reasons for the reflow solder beads are as follows:
1. The quality of soldering largely depends on the solder paste
The metal content in the solder paste, the degree of oxidation of the metal powder, and the size of the metal powder can all affect the generation of solder balls.
2. The steel mesh has a great influence
a. Stencil opening
Most factories will open the stencil according to the size of the pad, so that it is easy to print the solder paste to the solder mask layer and produce tin beads, so it is better to have the opening of the stencil smaller than the actual size.
b. Thickness of steel mesh
The stencil Baidu is generally between 0.12~0.17mm, too thick will cause the “collapse” of the solder paste, resulting in tin beads.
3. The placement pressure of the placement machine
Mounting is that if the pressure is too high, the solder paste will be squeezed to the solder resist layer, so the mounting pressure should not be too large.
Post time: Apr-06-2023