Description / Abstract:
Purpose. This procedure describes the standard
equipment configuration and test method for line purge and bell cup
cleaning of waterborne basecoat using low Volatile Organic
Compounds (VOC) and low Hazardous Air Pollutants (HAP) purge
solvent solutions.
The procedure can also be applied, on an as needed basis, for
the cleaning capability testing of solventborne basecoats using
higher VOC purge materials per 9984037 and 9984304.
The purpose of a line purge and bell cup wash cycle is to clean
out the paint line and the fluid tip and to remove any paint
overspray which has collected on the exterior surfaces of the bell
cup during the normal paint application process.
This test procedure should be performed during the development
of new purge materials prior to submission of proposals to GM.
Note: It should be noted that this test
procedure does not represent actual production conditions, but
rather represents a screening method that provides a relative
comparison of the cleaning effectiveness between a known and/or
verified baseline purge material and one or more test materials by
comparing the build-up left on an applicator after a given number
of test cycles.