Now that the rush is over, many of the exempt applications have been updating their designs, without trying new solders. One example is company that I have been working with that updated their entire process with new equipment. Because of the great rush for new equipment, this technology company has also bought new printers, placement machines, reflow ovens and x-ray machines. They updated everything across the "board" (pun intended). Except the solder paste that they have been using since the dawn of man. Well, this is an exaggeration, as this particular application has always been a niche application, using a specialty solder. But, since the inception of the product, they have been using the same material; an older formulation for which we developed a replacement flux vehicle specifically designed for the alloy that they were using.
Imagine, you purchasing one of the new "retro" muscle cars (insert your favorite…), yet still having the bias-ply tires you remember on the original. At what point does the performance of the total package suffer from the flaws in the original design? Something that is not directly related to the output of the car yet can have a measurable impact on the total package.
The same scenario occurred with this customer. After they went into production with the updated process, the solder quickly became the weak link in the chain, and they called us for help. It seems that under the old process, the board-by-board processing technique covered the flaws in the older formulation paste that was handed down from project to project, and once everything else was under control, it stood out. This is where the "new" formulation, specifically designed for the alloy that they were using, was introduced. And it worked. Perfect.
So, the moral of my story is where does the solder fit in? Is it a modern component in your modern process? Or is it bias-ply in a radial world?
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