Experiencing Technical Difficulties (resonant) wrote,
Experiencing Technical Difficulties
resonant

I am shunned at work

A supplier makes custom inductors for us, consisting of a copper coil with an exterior ferrite shell. The shell was larger than the coil, to allow for thermal expansion. The inductor is used in a high-vibration aerospace environment. We therefore can't allow the shell to move relative to the coil, or it will repeatedly bash against it and fracture. The supplier applied a continuous strand (or "bead") of high-strenth two-part epoxy to one edge of the shell, to hold it in place while still allowing for expansion. In 2011, we noticed that this bead of epoxy could fracture when exposed to the rapid thermal shock of our aqueous cleaning process. We requested that our supplier add a second bead of epoxy to the edge of the shell, to provide adequate mechanical strength. That made the problem go away, so our supplier made a permanent change to their manufacturing instructions to include a dual epoxy bead.

Last week, our customer reported finding loose inductor shells. I was surprised, as it had been years since we had seen this issue internally. We immediately collected the most brilliant engineers at our customer, our supplier, and at my company. I described the issue we had seen in 2011, and our customer concurred that the current failures matched the historic defects. I described the changes that the supplier had made to their manufacturing instructions years before. Our supplier reported that their instructions remained the same. The engineers at my company then questioned whether or not the operators at the supplier were following the manufacturing instructions and taking the time to perform both applications of epoxy. All agreed that this was the next line of inquiry that our investigations must take.

I then summarized:

Two-bead, or not two-bead; that is the question.

My customer, my supplier, and my co-workers groaned, and refused to speak to me for the rest of the day.
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