Five levels of service-and-repair support help SCS customers maximize availability and uptime...
"...stable paint viscosity produced dramatic reductions in viscosity-related defects such as orange peel, gloss and sag, and temperature-related defects such as dry spray."
- Roush, First-tier auto supplier
more »
Case Study #5
The Opportunity
Chrysler's Jefferson North Assembly Plant was experiencing seal leaks at the windshield and deck (rear) window in their glass installation cell. These seals are composed of high-viscosity (>1M cps) urethane and are robotically applied to the glass directly before installation to assure proper location of the gasket material. A specially designed extrusion nozzle creates a delta (?) shaped seal profile along the perimeter of the glass panel. The triangle shape and pre-defined height work together to assure that all voids in the receiving channel are completely filled to provide proper adhesion and prevent wind and water leaks. An investigation by the plant engineering staff determined that the problems with the seal were the result of temperature variations in the high-viscosity urethane due to its steep temperature vs. viscosity curve. At lower temperatures, the viscosity of the urethane increased sharply resulting in a high-pressure drop in the dispensing system leaving insufficient pressure at the extrusion nozzle to form the seal with the proper peak. Conversely, at higher temperatures the viscosity of the urethane dropped sharply, and though the seal was properly formed, the reduced viscosity allowed the peak to slump to below required height in the short time between application and glass installation. In each case, the result was an inadequate seal. The only option available once the glass was found to leak was to remove (destructively) and replace the glass panel resulting in high scrap costs. Chrysler personnel turned to SCS to devise a method for maintaining proper urethane temperature at the point of dispense.
The Solution
Because this was an established, operating fluid-transport system there was a great desire to minimize both downtime and changes to the fluid path. SCS developed a temperature-control package designed to retrofit into the existing system. Based on SCS' Profile Traced Cover Assemblies (patent pending), the system turned the material transport headers into tube-in-tube heat exchangers without disturbing the flow path. These selections allowed the installation of 99% of the system during normal production, with no unscheduled downtime.
The Results
By implementing the temperature control system, Chrysler was able to select and maintain the optimal application temperature for the urethane, independent of changes in ambient temperature. The result was a reduction in leak-related rejects of more than 80%.
Back