IMMERSION WAVE SOLDERING PROCESS

Immersion wave soldering is a new technique for soldering advanced printed circuit boards. In this process, an assembled and fixtured printed circuit board is immersed in a fluxing fluid and preheated to the soldering temperature. The fluxing fluid is glycerine activated with ethylenediamine tetra-acetic acid (EDTA). After preheating and while still immersed in the fluxing fluid, the fixtured board is passed over a tin-bismuth eutectic (42% Sn, 58% Bi) solder wave. This technique has several advantages over conventional soldering processes, including elimination of solder dross formation, improved control over solder deposition, reduced thermal shock, easier cleaning after soldering, and improved flux effectiveness.