A familiar client called. He wanted me to be at his manufacturing plant ASAP to inspect his rinsing system, to tell his management that it was fine, and to stop bugging him about it. He said he was doing things the right way.

NOT SO FAST, MY FRIEND!
My client’s management had another point of view. They had nearly lost a major position in gold-plated connectors. Blame for plating quality was ascribed to carryover of soil components as dragout from the cleaning to the rinsing to the plating system.

His plant had a five-stage countercurrent flow rinse bath system. His performance data purported to show that the water leaving with the rinsed parts was indistinguishable from virgin rinse water.

My client wasn’t worried about dragout. His system was designed to rinse dragout from parts. His performance data showed it did that. Isn’t that what you would say about your rinsing system?

AT THE SITE
Our inspection of his system showed the unexpected— to my client. The design was unexpectedly inadequate. The performance data was unexpectedly misleading. Also unexpectedly, dragout should have been a major concern.

At my client’s facility, the connectors were contained in a perforated cylindrical basket. The basket held about 25 gallons of water with the parts. It rotated within a 150 gallon rectangular tank at 2.5 rpm. Contact time per stage was one minute. We measured fluid dragout volume as about three gallons, as the basket held many connectors. Remember, dragout is the mixture of soil, cleaning agent, solvent or water, and particles left on the parts after cleaning is complete.