Issue link: https://iconnect007.uberflip.com/i/989774
JUNE 2018 I SMT007 MAGAZINE 75 consistency and reducing the coefficient of variation. The data generated in this arm of the study echoes the findings of the previous DOE in that that best quality prints were produced on square and solder mask-defined pads, whereas the worst prints were produced on circular, non-solder mask-defined pads (aka copper defined pads). In between the extremes are mask-defined circular pads and copper- defined square pads. For the sake of brevity, the two middling conditions are not reported; rather, the best-case scenarios are presented, and the worst-case scenarios are explored in greater depth. Figures 7 and 8 represent the best-case scenario for achieving quality print results. It combines SMD test pads with square apertures Figure 8: Print performance of Type 5 powder with best-case scenario pad design. Figure 7: Print performance of Type 4 powder with best-case scenario pad design.