This test method is designed to provide load versus deformation response of plastic films under essentially multi-axial deformation conditions at impact velocities. This test method further provides a measure of the rate sensitivity of the plastic films to impact.
Multi-axial impact response, while partly dependent on thickness, does not necessarily have a linear correlation with specimen thickness. Therefore, results should be compared only for specimens of essentially the same thickness, unless specific responses versus thickness formulae have been established for the plastic films being tested.
For many plastic films, there may be a specification that requires the use of this test method, but with some procedural modifications that take precedence when adhering to the specification. Therefore, it is advisable to refer to that material specification before using this test method. Table 1 of Classification System D 4000 lists the ASTM materials standards that currently exist.
The values obtained by this test method are highly dependent on the method and conditions of film fabrication as well as the type and grade of resin. Results can vary significantly, depending upon sample quality, uniformity of film gage, die marks, contaminants, and so forth.