Testing acc. to ISO 22557: Paints and varnishes – Scratch test using a spring-loaded pen
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Testing methods
Our test laboratory performs testing according to DIN EN ISO 22557 to determine the scratch resistance of coatings. A spring-loaded test pen is moved across the surface at a defined test force and the resulting damage is evaluated. The method can also be applied to curved surfaces and directly to components.
Depending on the test objective, a spherical stylus or a disc stylus is used. In addition to scratch resistance, the method can be used to evaluate susceptibility to metal marking, writing effects and fingernail-like mechanical stresses. It is therefore particularly suitable for assessing high-quality decorative and functional surfaces.
Testing according to DIN EN ISO 22557
Method A uses a carbide spherical stylus, while Method B uses a disc stylus that is moved across the coating surface. The test force of the spring-loaded pen can be adjusted within a range of 0.5 N to 20 N. Stylus type and test force are selected according to the surface property to be evaluated.
The test can be performed at a specified constant force as a pass/fail test or with progressively increasing test force. In the latter case, the lowest force at which defined surface damage first occurs is determined. Evaluation criteria can include the first continuous visible scratch, a continuous perceptible scratch or rupture of the coating.
Applications of the test
The test is suitable for comparative evaluation of the mechanical resistance of coated surfaces to localized scratching and marking. It is particularly relevant to painted and coated plastic components, decorative surfaces and automotive interior components.
The variable test force allows different coating systems, paint finishes and surface modifications to be compared in terms of their sensitivity to mechanical damage. The method therefore supports materials development, process optimization, quality control and failure analysis.
Related tests
Another standardized method for determining the scratch resistance of coatings is DIN EN ISO 1518-1 using a constant load. Coating adhesion can additionally be evaluated using the cross-cut test according to DIN EN ISO 2409.
For automotive interior surfaces, FILK also offers accredited scratch testing according to BMW GS 97034-9 and Volkswagen PV 3952.
