Preforms are put between surfaces that are being soldered. The preform area is heated
locally with a soldering iron, torch, hot air tool, or the entire assembly can be passed through
a suitable oven. The assembly should be heated above the liquidus temperature of the solder alloy being used.
Ideal temperatures and times for reflow and intermetallic formation depend on assembly, process and alloy
used. This allows manufacturing soldering operations to be completed without using extra liquid fluxing agents
which reduce throughput time and increase process yield by delivering precisely the right amount of flux to solder surfaces together.