Soldering issues
Flux spattering, Solder ball (Solder Pastes)
Flux spattering and the issues of solder paste
Flux of solder paste may occur spattering in reflow heating.
Flux adhering to the connector part or contact part of memory socket may cause poor conduction and malfunction.
Causes of flux spattering in solder paste
Causes of flux spattering is the rapid boiling of flux.
In reflow heating, gases are generated in the flux as the solvent evaporates and the activator decomposes.
The temperature of the solder paste rises rapidly in the Heating zone 1, which is from the start of reflow to preheating, and in the Heating zone 2 which is from the end of preheating to main heating.
It generates gas from the flux at once, boils and causes spattering.
Also, when a large amount of gas is generated after melting the solder, Gas tends to accumulate in the molten solder, and spattering is likely to occur when this gas escapes.
Measures against flux spattering in paste
Measures against flux spattering are as follows.
<By reflow profile>
· Decrease the temperature gradient of temperature rise zone 1 and temperature rise zone 2.
<By solder>
· Change the active agent in the flux to one with a wide decomposition temperature range.
The generated gas does not accumulate inside the molten solder, and it escapes every time, so it hardly leads to spattering.
We have less spattering type solder paste, so please contact us.
Solder ball
Solder ball is a phenomenon where solder powder is left behind around the soldered part after reflow.
In addition to appearance problems, insulation resistance value will decrease if the amount generated is large.
Cause of solder ball
Causes for solder ball are from both devices management and solder paste.
<from devises management>
· High temperature inside the printing press, high humidity
· Cleaning failure of metal mask
· Misalignment of metal mask
· Clearance defect of metal mask
· Reuse the paste once used
<from solder paste>
・Oxidation of solder powder
Measures against solder ball
Management and maintenance of printing presses are important to prevent solder balls. On the other hand, adding an appropriate activator to the flux of solder paste reduces solder balls. Our solder paste has taken measures in flux to reduce solder balls.
