Faced with the difficult task of removing high-resin, polyurethane paint that had accumulated to one-and-a-half-inches thick on bumper carriers, Midwest Water-blasting Company, Tecumseh, Michigan, turned to ultra-high-pressure equipment.
Plant operations at the large automotive plant shut down over a holiday weekend to clean the carriers. Excess build-up of polyurethane paint was interfering with bumper carrier alignment in the paint booth. This caused erroneous computer readings that resulted in misguided robotic paint spray applications.
"High-resin polyurethane is a highly elastomeric material. It is one of the toughest paints to remove," commented Al Schafer, president of Midwest Waterblasting Company. "This is some of the roughest work we do, and only ultra-high water pressure can remove this build-up."
A total of 370 carriers occupy the conveyor line. Each carrier handles four plastic bumpers. Midwest Waterblasting used Jet Edge Model 36-25OD diesel-powered Intensifier pumps and four Ultra-Lite Lances to do the job. The equipment was set up and ran 62 hrs non-stop.
The system was fed by an on-site water supply. Each lance has an 0.027-inch orifice. Both pumps provide the lances with water pressurized to 36,000 psi. The water easily cut through the one-and-a-half-inch thick paint build-up, cleaning the carriers to bare metal.
During the cleanup, precise control of water velocity and careful application methods prevented bumper carrier damage. Consistent production required the correct orifice and lance combination, while maintaining the proper standoff distance between lance tip and target material.
Because of the nature of ultra-high-pressure waterjet technology, carriers were cleaned without using heat, which eliminated spark ignition or metal fatigue from thermal stress. Use of ultra-high-pressure water also helped eliminate hazardous airborne particles that are inherent with other removal techniques. The practical elimination of contaminants increased operator efficiency without the need for ventilation or containment facilities.