Puncture Fixture for Plastics Testing

ASTM F1306 Puncture Fixture

for Plastics Testing

Theory:

Puncture tests are used by many plastic film manufacturers to determine the strength of their packaging. Ideal barrier films must be able to withstand puncture while also maintaining appropriate tensile strength and material thickness. Lean manufacturing techniques such as Six Sigma have led many companies to seek manufacturing methods that reduce raw material costs. Plastic film manufacturers will aim to thin their films by as much as possible while still maintaining high puncture strength.

Geometry:

Standard films should be tested at about two and a half microns and be of uniform thickness so that a repeatable test can be made. 2x2" squares are commonly used but the square size can vary based on the exact dimensions of your puncture fixture. Our standard design is for 34.9mm. 

The size of the puncture implement is also important and can vary based on the elasticity of the material. You must achieve full puncture for this test to deliver the required data. 

Solution:

There are several different styles of puncture fixtures as well as puncture implements. The diameter of the hole opening compared to the diameter of the test plunger is a critical dimension for ASTM F1306 and similar puncture tests. Also, the plunger must be able to achieve a full puncture so films with high elongation and high puncture strength must be noted. On this fixture the diameter of the hole is 34.9mm and the radius of the puncture plunger is 1.6mm. 

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The puncture fixture can attach onto any universal testing machine by means of clevis pin style adapters. The fixture has a female 5/8" coupling and uses a 5/16" locking. Universal Grip recommends the Quasar line of universal testing machines from Galdabini. 

Analysis:

The calculations for puncture testing are relatively straight forward. The Force to Break is the peak load at which the sample is punctured. The Energy to Break can also be calculated and this requires positional or displacement information. Other derivative analysis can be tabulated which highlights deviations and variability between tests and specimens. The Galdabini Universal Testing Machine is capable of testing according to ASTM F1306.