ASTM D1709 Dart Drop Impact Test for Plastic Film, Explained
Representative Infinita Engineering Visual explaining the four-step workflow for Astm D1709 Dart Drop Impact Plastic Film.What Is the Dart Drop Impact Test?
ASTM D1709 is the Standard Test Method for Impact Resistance of Plastic Film by the Free-Falling Dart Method. It determines the missile weight, dropped from a fixed height, that causes 50% of test specimens to fail — a key quality and design metric for flexible packaging films.
Test Methods A and B
- Method A: 38.1 mm diameter hemispherical dart head, dropped from 0.66 m; applicable for films failing at roughly 50 g up to about 2 kg
- Method B: 50.8 mm diameter hemispherical dart head, dropped from 1.50 m; applicable for tougher films, roughly 0.3 kg to 2 kg failure range
Test Procedure
Film specimens (commonly 230 x 230 mm) are clamped in an annular specimen holder, typically 5 inches inside diameter, with the dart positioned above the specimen center and released via pneumatic or electromagnetic mechanism. Two data reduction techniques are permitted:
- Staircase method: dart weight is increased or decreased by a fixed increment after each test depending on pass/fail outcome, continuing until a target number of failures and non-failures is recorded
- Alternative (group) method: specimens are tested in groups of ten at a fixed weight, with weight varied in uniform increments between groups
Both methods produce statistically equivalent failure-weight values and precision.
Sample Requirements
Specimens must be free of pinholes, wrinkles, or other imperfections unless those defects are the specific variable under study. Films are conditioned per standard atmosphere requirements (23C +/- 2C, 50% +/- 5% RH) for at least 40 hours prior to testing.
Also Read – Damage Resistance Testing of Sandwich Constructions: Methods & Standards
Industry Specifications Referencing ASTM D1709
- ISO 7765: international equivalent free-falling dart method (differs in conditioning and data interpretation conventions)
- Common applications: food pouches, industrial liners, co-extruded and barrier films
Conclusion
Dart drop testing is the standard benchmark for flexible film toughness, but Methods A and B are not interchangeable, and results can’t be compared to rigid-material impact tests like Izod or Charpy. Method selection should match the expected impact resistance range of the film under evaluation.
What is the ASTM D1709 dart drop impact test? ASTM D1709 measures the impact resistance of plastic film using a free-falling dart. The result represents the dart mass required to cause failure in 50% of the tested specimens.
What materials can be tested? The test is primarily used for flexible plastic films and thin sheeting with a nominal thickness of up to 0.25 mm. Common examples include polyethylene, polypropylene and packaging films.
How is the test performed? A film specimen is securely clamped over a circular opening. A hemispherical dart with an attached weight is dropped from a specified height onto the centre of the specimen.
What is the difference between Method A and Method B? Method A uses a 38.10 mm dart dropped from 0.66 m. Method B uses a larger 50.80 mm dart dropped from 1.52 m and is generally suitable for films requiring greater impact energy.
What is the staircase testing method? The staircase method adjusts the dart weight after each test. The weight is increased when the film does not fail and decreased when failure occurs until the 50% failure mass can be calculated.
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