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58 SMT007 MAGAZINE I SEPTEMBER 2021 is data was confirmed by a large consumer electronics manufacturer who converted their wave soldering alloy from SAC 305 to SACX Plus 0807 and SnCX Plus 07. ey reported a 50% reduction in dross generation. Conclusions Primary attach barrel fill results, using SACX Plus 0807 alloy to assemble PTH connectors onto a 20-layer, 120-mil thick test vehicle, were comparable to those test vehicles assembled using SAC305, with yield levels of 99.7% on standard designed connectors. is soldering performance enables SACX Plus 0807 to make good barrel fill according to Class 3 hole-fill re- quirements with board thickness at 120 mil or more under suitable soldering process param- eters. SnCX Plus's Cla s s 2 - h o l e f i l l r e q u i r e - ments should be attain- able for PCBs up to 2.4 mm thick, with five to seven seconds contact time. Low/no silver alloys signif icantly reduce the copper dissolution into wave and selec- tive soldering baths, reducing the frequency of solder bath mainte - nance or replacement. Reducing the rate of dross creation also low- ers the volume of sol- der purchased, red u c - i n g t h e c o s t o f own- ership. Mo s t i m p o r t a n t l y, r e d u c i n g t h e p e r - cent of silver in the alloy used, significantly r e d u c e s t h e c o s t o f solder purchases. SMT007 References 1. Pandher, R. et al., "Drop Shock Reliability of Lead-Free Alloys—Effect of Micro-Additives," Pro- ceedings of 57th Electronic Components and Tech- nology Conference, Reno, NV, May 2007. Mitch Holtzer is technical knowledge leader, global R&D, MacDermid Alpha Electronics Solutions. Figure 6: Dross generation as a function of (top) time, and (bottom) alloy.