Communication

The parts came back from quality control with a bright red rejection tag attached. REJECTED — SURFACE FINISH NONCONFORMING. I picked up the tag and read the reason code: “Surface finish exceeds maximum allowable roughness per print specification. Ra 3.2 micrometers maximum required. Measured value per profilometer: Ra 4.1.” I looked at the parts in the red bin. They were a batch of hydraulic manifold blocks — 4140 steel, with a 16mm hole drilled 300mm deep using a BTA drill. I’d run them myself that morning, and I knew the surface finish was good. Not a mirror finish — BTA drilling doesn’t leave a polished bore — but perfectly adequate for the hydraulic application. The customer had been accepting similar finishes from us for years without a single complaint. ...

The Customer Who Refused to Let Me Inspect the Part I’ve been running CNC lathes for about fourteen years now, and if there’s one thing I’ve learned, it’s that gut feelings on the shop floor are usually trying to tell you something. This story starts with one of those feelings, and it almost ended with a fifteen-thousand-dollar chargeback. The job came in through our regular quoting process. Nothing special about it on paper. But from the moment the material showed up, something did not sit right with me. I have learned to pay attention to that feeling. ...