Making the switch for switch components

Victor Wagner of Therm-O-Disc, Incorporated, a subsidiary of Emerson Electric, describes his company’s experience with a centrifugal liquid carbon dioxide cleaning system for removing silicone thermal test fluids from bi-metal disks.

“We went on-line in our London, Kentucky, facility on December 1, 1997,” said Wagner. “The assemblies we clean are electrical switch components with silver contacts.  The contacts tend to attract contaminates during the manufacturing and assembly processes, and, if improperly cleaned, will result in a rejected component.  The LCO₂ cleaning system was acquired to replace vapor degreasing units.  “Our process engineers tested many alternatives to solvent cleaning,” Wagner remarked.  “Based on the cleanliness results, operating costs, and environmental benefits, they felt the CO₂ cleaning system presented an excellent opportunity for us to move away from chemicals into a dry cleaning process with no future environmental risks.  The system cleans our parts as good as or better than our past vapor degreasing process.”
“Since going on-line we have not encountered any significant maintenance problems with the CO₂ system.  The typical maintenance situation involves the replacement of “O” ring seals in the two pumps.  We drive the pumps with nitrogen gas generated from an on-site liquid nitrogen tank.  Currently, we consume approximately 600 pounds of CO₂ every 10-14 days-depending on production-and have no disposal or environmental concerns related to our cleaning process (average cost of CO₂ is $0.14 per pound).”

In summary, Wagner stated that his company is “very pleased” with their transition to LCO₂ cleaning.  “I should add that we found the system to be very operator-friendly,” he noted.  “We have trained five different operators, and none of them had any trouble learning the functions and cleaning procedures.”

Source:
“Liquid CO₂ Immersion Cleaning: The User’s Point of View”, Parts Cleaning, April 1999