During the coating of steel or aluminium strips in high speed coil coating machines the liquid coatings (varnishes)are stressed to an extremely high degree. Therefore it is absolutely essential to test the mechanical hardness of these varnishes the laboratory first.
During the test the coating is poured into a small container and subjected to very high shear conditions (up to 64.000 rpm). These conditions are created by the counter-rotating high speed propellers.
After the test the coating is applied to a test panel and baked at different temperatures. The subsequent testing of the surface shows whether the coating meets the required quality standards.