Soldering issues
Printing problems
Printing problems
(1)Transfer problems
A required amount of solder paste is not transferred to the board, causing insufficient wetting and strength at the soldered part.
(2)Sagging in printing
The shape of the solder paste collapses after printing or solder paste is transferred excessively, causing chip side balls or bridges at narrow pitch parts.
Cause of Printing problems
The cause is viscosity change of solder paste. Increase in viscosity may cause transfer problems, decreasing may cause sagging in printing.
Measures against Printing problems
There are measures with solder paste and equipment setting, respectively.
(a) Measures with solder paste
By using solder paste with little change in viscosity even if continuous printing for a long time, it is possible to take measures against both transfer problems and sagging in printing.
(b) Measures with equipment setting
You can take measures by managing the temperature and humidity inside the printing machine.
When the temperature inside the printing press is high, the viscosity of the solder paste temporarily decreases and print sag is seen. Over time, the viscosity increases due to the chemical reaction of the flux and the solder powder, resulting in transfer failure. On the other hand, when the temperature is low, the viscosity of the solder paste decreases and transfer failure occurs.
If the humidity inside the printing machine is high, deterioration of solder paste due to moisture absorption, viscosity increase occurs, transfer failure occurs. Also, if the humidity is low, the solvent in the flux volatilizes, which increases the viscosity of the paste, which may cause poor transfer.
Solder paste with stable printability
We have solder paste with low viscosity change and stable printability even for long time printing so please contact us.
