Pendulum Impact Tester for Flexible Packaging Film Toughness

Flexible packaging films face sudden dynamic impacts during distribution—snack bags dropping from shelves, pharmaceutical pouches jostling in cross-border shipping, or personal care sachets being compressed on high-speed sorting lines. If film toughness is inadequate, pinhole leaks can impair barrier performance, while seal failure can release product and cause costly recalls. Impact resistance is therefore a key indicator of whether a flexible package can survive real-world distribution.

A pendulum impact tester quantifies this property. By simulating film rupture under dynamic loading, it provides comparable, traceable energy data for incoming material inspection and finished-goods quality control in food, pharmaceutical, and personal care applications.

1. How a Pendulum Impact Tester Tests Film

The test principle is simple: a hemispherical striker moves at controlled velocity and punctures a clamped film specimen, measuring the energy absorbed at rupture. The film is held flat in an annular fixture, the pendulum is released from a preset angle, and the striker hits the center. The energy required to break the film is reported as pendulum impact resistance.

Instruments usually offer selectable ranges—commonly 1 J, 2 J, and 3 J—by changing weights, with resolution down to 0.001 J, covering monolayer polyethylene to multilayer laminates. Pneumatic clamping and release reduce operator variability, while a horizontal auxiliary plane minimizes error. Standard practice tests ten valid specimens per group and averages the results. The pre-lift angle is typically 150°, impact velocity is constant, and geometric parameters follow relevant standards for repeatability and comparability.

2. Which Standards Apply to Pendulum Impact Testing?

Choose the standard required by the buyer or destination market.

ASTM D3420 — USA

Standard test method for pendulum impact resistance of plastic film. Procedure A uses 60 mm specimens; Procedure B (Spencer) uses 89 mm specimens. Data from the two procedures are not comparable. There is no known ISO equivalent.

GB/T 8809 — China

Applies to plastic films up to 0.25 mm thick; composite films may refer to it. It defines A and B methods with different striker and fixture combinations. The revision adds low-temperature testing, C/C2 strikers, and requires discarding specimens that slip.

NF T54-116 — France

Pendulum impact method for plastic films. Uses 100 × 100 mm or Ø100 mm specimens and a hemispherical striker, typically Ø38.1 mm. Reports energy in joules and records rupture appearance—clean tear, stretching, or shattering.

A well-configured tester can support multiple standards by changing strikers and fixtures. Confirm geometry and fixture compatibility with the supplier before purchase.

3. How to Select a Pendulum Impact Tester for Flexible Packaging

Selecting the right instrument is not merely a purchasing decision—it is a matter of aligning test requirements, standard compliance, and budget.

• Material: For PE, PP, PET, and laminates, use a film-specific tester with a hemispherical striker and annular clamp, typically 1–3 J. Do not use a metal impact tester, which operates at 150–750 J.
• Energy range: Keep readings within 10–90% of full scale. Use the 1 J range for about 0.5 J and the 3 J range for about 2.5 J.
• Clamping: Pneumatic clamping improves repeatability. Automatic statistics and data export help high-volume laboratories.
• Calibration: Confirm friction-loss calibration and reference specimen verification. Ask for local service and calibration support.

Conclusion

A pendulum impact tester turns film toughness into a traceable energy value linked to drop, compression, and vibration resistance in real distribution. Select the instrument around the required standard—GB/T 8809, ASTM D3420, or NF T54-116—and maintain routine calibration. For export projects, confirm the buyer’s standard before purchase.