Scratch testing device KKO/KFN/LHP BMW EK 341
- For testing the scratch resistance of synthetic surfaces in the receiving area a device which is easy to operate, allows quick tests and allows only small impact on the results by operator errors of the testing staff is required.
The device consists of a plane, a hard metal cutter and the load spring. A spring pushes the test cutter on the tapered bottom side of the plane. The pushing force of the spring can be adjusted continuously variably on a load scale, according to the synthetic material to be tested. The plane is then led over the specimen surface with a steady speed.
The criteria for scratch resistance is the visibility of scratches.
This simulates which impacts leave scratches from fingernails on the instrument panel or on Plexiglass surfaces and up to which distance these are visible with the naked eye. The testing device has to be designed in such a way that operator errors of the staff will only have small impact on the results. A semicircular hard metal cutter is positioned on the bottom side (specimen surface) of a tapered plane. This cutter can be tightened with a spring in order to produce different scratching traces. The criteria for determining the quality of the tested material is the visibility of scratches from ca. 40 cm to 80 cm from the position of the driver and front-seat passenger, including the consideration of the view angles. The main criteria for defining the distance are the usual distances between eye and surface when driving and when boarding and leaving the vehicle.
The device detects variations in the adhesive strength between finishing paint and filler. It is suitable for measurements with a comparative value or without.
In the test a graver with a hard metal cutter is pressed against a specimen in an angle of 10°. The tension of the spring can be set continuously variably on a load scale. The measured value is the spring tension with which the finishing paint is only just chipped.
|Geometry of specimen:||Synthetic surfaces / coatings|
|Testing standards:||BMW EK 341|
|Dimensions (testing device):||200 x 60 x 60 mm (W x D x H)|
|Weight (testing device):||ca. 500 g|