instron water tank fixture

Problem

Currently, many force testing on the Instron occurs at room temperature. Without access to an Instron Bath Attachment, there needs to be another method of performing force testing of samples in a heated bath environment.

Objective

To design a method and fixture to secure a water tank to the base of the Instron and perform tensile and compression tests with it. The fixture must also be able to securely hold the water tank in place but also be easily removable.

Skills Employed

SOLIDWORKS 3D CAD model
3D Printing (FDM)
Machine shop manufacturing and tool use (tapping, drills, sanding)
Testing fixture design/mechanical testing
Instron Tensile Testing

Figure 1. 3D CAD Model Assembly of an Instron adaptor for force testing in a large heated water bath (without one stand for better visualization of the fixture)

Approach

I first started by understanding the design requirements needed for this fixture. After chatting with a co-worker who is typically in charge of the fixtures, we were able to generate some design ideas. I was then able to start drafting these ideas in SOLIDWORKS. Most of these components were test printed using the FDM. After test printing, getting parts outsourced and manufactured, and ordering parts from McMaster-Carr, I was able to start the test assembly. I quickly realized that some mechanisms needed some improvement. For instance, the corner pieces I created needed to have some slight adjustments in order to keep the piece from rotating when turning the screw. After small design changes were made, the parts were made out of Delrin and was fully assembled for testing.

Results

The fixture could successfully secure a water tank and related tensile/compression fixture to the Instron. Looking back, if I were to do this again, the first thing I would change is to make the base plate thinner and less heavy.