scope:

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.