Cupping Test Experimental Objective
Its objective is to evaluate its anti-cracking and seperate performance within the stands and condition.
GB/T 9753-88 “The paint and varnish cup drawing test”
Main points of the test method
People push the sphere punch to the back of the lacquer test board with the same speed. And try to observe weather it cracks or not.
When the film damages, the least depth is the cupping test index. It differs the shock resistance performance.
Material and apparatus
Erichsen tester and the steel. The thickness is 0.30～1.25 m, and the width and length is within 70 mm.
Fix the test panel on the instrument and the coatings should against the film. When the punch at zero, the top touches the test panel. Adjust the test panel, and point of intersection, between the central axis and the test panel, should within 35mm. Open the instrument, push the punch to the test panel, until to the authorized total depth or it occurs cracking.
Make the experiment according to the authorized total depth. And put out the test panel, when it reach the authorized total depth. Observe weather it cracks or not.
The evaluation is according the results. When people do the experiment according to the experiment results within the least depth, it shows the results.