Automatic Scratch Testers
Automatic Scratch Tester BGD 520-1 (ISO 1518-1: Constant-loading) and BGD 520-2 (ISO 1518-2: Variable-loading)
ISO 1518 (Paints and varnishes -- Determination of scratch resistance) specifies a test method for determining under defined conditions the resistance of a single coating or a multi-coat system of paint, varnish or related product to penetration by scratching with a scratch stylus loaded witha specified load. Penetration of the stylus is to the substrate, except in the case of a multi-coat system, in which case the stylus can penetrate either to the substrate or to an inter mediate coat.
Before 2011, there was only one standard which being used to evaluate paint scratch resistance, which against to evaluate scientifically to paints scratch resistance under different applications. After revision of this standard in 2011, this test method has been divided two parts: One is constant-loading, i.e the loading to panels is constant during the scratch test, and the test results is shown as max. weights which don’t damage coatings. The other is variable loading, i.e. the loading on which stylus loads test panel is increased continuously from 0 during the whole test, then measure the distance from finial point to the other point when the paint begin to appear scratch. Testing result is shown as critical loads.