Yes, the Go Direct® Structures & Materials Tester (GDX-VSMT) (or Vernier Structures & Materials Tester (VSMT)) has the range and resolution to measure the stretch and strength of thin plastic films, such as household kitchen Saran Wrap. But mounting a sample in the Structures & Materials Tester can be difficult. One solution is to 3D-print a fixture like one shown below.

This plastic film fixture consists of two parts:

The top part clamps to one end of a sample. The part is 3D-printed and supported by 5/16″ hex bolts. The hex bolts in this image are 4.5″ long; longer bolts would allow for a greater range of sample lengths.

The bottom of the fixture attaches to the U-bolt that comes in the Structures & Materials Tester tackle kit. It clamps to the other end of the sample.

Both ends of the fixture feature a cylinder split along its length. One end of the sample is fed through the split cylinder and then wrapped around the cylinder. By mounting the sample in the Tester this way, the plastic film can be pulled without resting across any edges.

You can download STL files for these fixture pieces here: https://www.thingiverse.com/thing:6816503

When preparing samples, keep the following in mind:

  • Take care when cutting the plastic film. Ragged edges often become the start of a tear across the sample when it is loaded during testing.
  • A single layer of plastic film can be difficult to work with. So you may consider folding your sample lengthwise once or twice before mounting and testing it. Of course, you will want to consider the folded thickness when evaluating your data.

Testing plastic films in the Structures & Materials Tester leads to interesting data because of the nature of the elasticity of plastic films. Under a given load, plastic films tend to stretch and permanently deform. This deformation can be seen in the force vs displacement curve for the film.

If you have used your Structures & Materials Tester to investigate plastic films, we would like to hear about it! Reach out to us via email (support@vernier.com).

Go Direct Structures & Materials Tester (GDX-VSMT) Troubleshooting and FAQs

Published: November 1, 2024. Updated: November 4, 2024.