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86 SMT Magazine • July 2014 MEETING FuTuRE STENCIl PRINTING CHAllENGES continues ARTiCLE A couple of observations can be made from Figures 15 and 16. First, a dramatic effect is seen in the type of reflow profile; the harsh environ- ment imposed by the hotter, longer profile ex- hausts the flux activity and oxidative resistance. The solder joints show observable effects of flux exhaustion giving an appearance of some de- wetting and graping (oxidized solder particles that do not coalesce into the solder joint). The type of reflow profile used shows the effect on the solder joints, as seen in the observable re- sults. The second observation is in regards to flux formulation. Note that a more dramatic ef- figure 13: 0201 components and 6 mil dot, water soluble paste (indium6.4): type 3, top; type 6, bottom. figure 15: 0201 components and 6 mil dot, water soluble indium6.4 type 6: ramp to peak, top; soak, bottom. figure 14: 0201 components and 6 mil dot, no-clean solder paste (indium8.9): type 3, top; type 6, bottom. figure 16: 0201 components and 6 mil dot, no-clean indium8.9 type 6: ramp to peak, left; soak, right.