By Shankar Srinivasan on Thursday, June 24th, 2010
In this energy era where the buzzwords are clean and green, people and companies alike are trying to do their part by using non-toxic and non-polluting materials, manufacturing processes, etc. As everyone knows, most soldering is accomplished using flux, which reduces the oxide layers on the surfaces to be joined thereby facilitating the joining process. The problem, however with fluxes is that they are corrosive. If you leave any flux residue on the surface there is the potential of corrosion which is a long term reliability problem. And the so-called ‘No-clean’ fluxes still leave flux residues which could potentially be a reliability problem.
Ultrasonic soldering is a fluxless process, which involves the use of acoustic vibrations that are transmitted using a soldering tool through the solder (acoustic transfer medium) to disrupt the surface oxides of metals, thereby enabling wetting of the materials. The elimination of flux removes cleaning, reduces hazardous waste, and eliminates corrosion thereby improving long-term reliability. In addition, this process obviates the use of metallization on difficult to wet materials like ceramics, glasses, etc. EWI has rapidly expanded this green soldering technology in combination with EWI SonicSolder, a Pb-free solder to join difficult-to-wet materials, and dissimilar metals and materials, for e.g., carbon fiber, SiC-Al, glass-ceramic, nitinol, etc.
To find out more about Flux-Free Soldering, see our video here.