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Summer is officially underway here in the Northern Hemisphere, and just like the temperatures, we’re turning up the heat in this issue and getting technical. Enter “Reliability Man,” the hero who must persevere against all the challenges thrown in his path.
It should come as no surprise that solder and solder joints are often at the center of attention in electronics assembly when discussing failures and reliability. Failed components aren’t under the direct control of the assembly operation nor is a board failure. But the joining of the two? That’s all you, contract manufacturers.
Thankfully, there is a significant amount of ongoing research into the specialty of solder joint reliability. Lead-free initiatives continue to drive this research. Industry watchers might say that we’re just now beginning to understand a few of the long-term effects of removing lead from solder. Some space and mil-aero applications continue to specify tin-lead solder only. For these applications, one can argue that environmental impact is simply not a high-priority concern; their products are not generally destined for the landfill. But long-term reliability in an environment where repair is not an option and safety and survivability are critical is a high-priority concern.
But the solder evolution isn’t limited to electronics. My neighbor is a plumber. Every Monday, he stops by my house to pick up three dozen eggs—about a day’s production when one’s residence comes complete with 50 laying hens—so I asked him how he likes leadfree solder for pipefitting. “It works,” he said, “but it’s a completely different skill set to use lead-free solder. It doesn’t behave the same.” Readers who work in the assembly industry know exactly what he’s talking about.
Don’t get me wrong; I’m not anti-RoHS. My point is that there is a great deal of ongoing research into materials, chemistries, thermal profiles, and precise process controls to create that completely different skill set my plumber neighbor had to teach himself. This is a time of great change and innovation for solders and conformal coatings.
As we put this issue together, it became clear that we needed technical papers on the cutting-edge of failure and reliability research. Not everyone dives deeply into the technical 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 lowtemperature 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 “Lowtemperature SMT Solder Evaluation.”
Treating the surface of aluminum for lowtemperature 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 electronics design and manufacturing.
This article originally appeared in July 2019 issue of SMT007 Magazine, click here.