This tester is designed and manufactured according to Chinese state standard GB 9639 and ASTM D 1709. It is applicable in energy test that causes plastic films and foils to fail under specified conditions of impact of a free-falling dart. This energy is expressed in terms of the weight of the dart falling from a specified height which would result in 50% failure of specimens tested.
1. Test Principle
At the beginning of the test, choose a test method, estimate an initial mass and Δm . Test, if the first specimen is failure, decrease the mass of the falling dart by decreasing poise of Δm. If the first specimen is not failure, add the mass of the falling dart by increasing poise of Δm. Test as the same. In brief, increase or decrease the Δm according to whether the former specimen is failure or not. After 20 specimens, calculate the total number of failure specimens N. If N equals to 10, test over. If N is less than 10, add specimen and continue to test until N is equal to 10. If N is more than 10, add specimen and continue the test until the number of non-failure specimen is 10. Then calculate the test results according to special formula.
2.Standard
ASTM D 1709,ISO 7765-1

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