Falling Dart method or Dart Impact is a traditional method that helps to assess the toughness and the impact strength of the plastic films. The test comprises of some specific configurations such as single dart, single drop height, and different weights of dart according to different standards that are introduced by national and international standardization authorities. All the standards explain different specifications of the apparatus that shows different results. Therefore, it is necessary for the manufacturers to consider the test requirement of the materials to understand the specifications of the apparatus so that best testing device can be selected out of the available options.
What are the Applications of Impact Testers?
Dart Impact Test is performed to measure the impact resistance of “Polyethylene Films” when the free-falling dart is applied to the film. This test is used to determine the energy that can cause polyethylene films to fail under specific conditions of the free falling dart. This energy is expressed as “mass or weight of a missile” that falls from a specified height which causes 50% failure of the sample.
Different Test Methods to perform Impact Test
ASTM D1709 – 15a explains two test methods, i.e., Test Method A and Test Method B:
- Test Method A – Test Method A explains that test is performed with the dart of 38mm ± 0.13mm, or5 inches ± 0.005 inches in diameter is dropped from a certain height of 660 m ± 1 mm or 26-inch ± 0.4 inches. The test is applied to the films whose impact resistance requires 50 grams or less to 6 kilograms of weight to fracture them.
- Test Method B – Test Method B explains that test is performed with the dart of 50mm ± 0.13mm or 2.0 inches ± 0.005 inches in diameter is dropped from a certain height of 1520mm ± 3 mm or 60 inches ± 0.25 inch. The test is applied to the films whose impact resistance requires 30 grams or less to 6 kilograms of weight to fracture them.
Presto’s Free Falling Dart Impact Tester by ASTM D 1709 – 15a
Presto Stantest manufactures Dart Impact Tester keeping in mind standard ASTM D 1709. Depending upon the specifications, impact strength and thickness of the sample, Method A or Method B are chosen. Following the method, the required number of samples is tested to measure appropriate starting point for the weight of the dart and measure the impact resistance of films.