Issue link: https://iconnect007.uberflip.com/i/1137649
JULY 2019 I SMT007 MAGAZINE 9 a time of great change and innovation for sol- ders and conformal coatings. As we put this issue together, it became clear that we needed technical papers on the cut- ting-edge of failure and reliability research. Not everyone dives deeply into the techni- cal papers, but for those of us whose job it is to reliably deliver failure-free products, we should be aware of the latest findings. This issue brings you some of the most insightful technical research from IPC APEX EXPO 2019. Dr. Jennie Hwang kicks the issue off with a piece titled "Learn From the Wise." And Nihon Superior's Keith Sweatman brings us his work on solder paste volume optimization for low- temperature BGA reflow. Ray Prasad follows with his column, asking, "Would You Prefer Shorts or Opens in Your Products?". Tony Lentz addresses solder powder size in his paper, "Size Matters: The Effects of Solder Powder Size on Solder Paste Performance." Then, Eric Camden's column discusses "The F Word"—failure. Following right behind is Rusty Osgood, et al., and their paper on "Low- temperature SMT Solder Evaluation." Treating the surface of aluminum for low- temperature soldering is the topic of discussion Nolan Johnson is managing editor of SMT007 Magazine. Nolan brings 30 years of career experience focused almost entirely on electron- ics design and manufacturing. To contact Johnson, click here. in Divyakant Kadiwala's paper. Next, Mike Fio- rilla looks at "Common Machine Errors and How to Avoid Them." Thermaltronics' Michael Gouldsmith and Zen Lee consider "Failures and Reliability in Soldering" at the tip of the soldering iron. Then, Young Song, et al., share their findings in overcoming nodules and scratches on wire bondable plating. Ranjan Chatterjee and Dan Gamota bring us the iNEMI Smart Manufacturing Roadmap dis- cussion on "Data Flow Considerations for the Electronics Manufacturing Industry." Then, Bob Wettermann discusses BGA and PCB warp- age, and Alfred Macha continues his series on becoming a preferred supplier. This time, he goes into detail on "The Six Pillars." So, put on your heat-resistant gloves; this issue is going to be as hot as an Arizona park- ing lot in July. Enjoy! SMT007 Scientists have discovered a way to alter heat trans- port in thermoelectric materials—a finding that may ulti- mately improve energy efficiency as the materials con- vert heat flow into electricity. Caltech theorists simulating the thermoelectric material lead selenide saw something surprising—a thermal wave that did not propagate. They determined the trick to potentially increasing energy effi- ciency in this material was to stop heat-carrying vibra- tional waves without thwart- ing electricity-bearing elec- trons. To verify the discovery, they called on experimen- talists to probe a real crys- tal. "Vibrational waves stop propagating in a perfect crys- tal because of nonlinear interactions between phonons," said Michael Manley of Oak Ridge National Laboratory (ORNL). The experiment used neutron scattering at ORNL's Spallation Neutron Source and the National Institute of Standards and Technology's Center for Neutron Research and X-ray Scattering at Argonne National Laboratory's Advanced Photon Source. The discovery improves understanding of thermoelec- tric performance and may enable unconventional heat transport in future materials. The research was published in Nature Communications. (Source: Oak Ridge National Laboratory) Engineering Heat Transport