What is solder paste? Learn about solder paste: composition, alloys, storage and processing in the SMT soldering process.
What is Solder Paste?
Solder paste is a mixture of fine solder powder particles and flux that is applied during stencil printing and forms the solder joint during reflow soldering.
Solder paste consists of fine solder powder particles (85–90% by weight) and flux. The most common lead-free alloy is SAC305 (96.5% tin, 3% silver, 0.5% copper) with a melting point of approximately 217 °C.
Properties and Application
Particle size is classified into types: Type 3 (standard), Type 4 and Type 5 for fine-pitch. Correct storage (2–10 °C) and limited working time are critical for print quality.
Frequently Asked Questions
Ready for your PCBA project?
SMTEC AG manufactures prototypes and series – fast, flexible and of the highest quality.
Request a quote →