Cups for Water Vapor Permeability test (ASTM E96)

thingiverse

These are specialized cups designed to evaluate the characteristics of polymer plastic films. To assess the moisture barrier performance of biofilms, I use them to conduct precise tests. The cups are filled with either water or a desiccant, and a sample is loaded in between the gaskets before being securely fastened with a convenient screw lid. As the water evaporates (or the desiccant absorbs water) in the cup over time, its level measured on a scale determines the "Water Vapor Permeability" compliant with the ASTM E96 standard, calculated as shown here: https://www.youtube.com/watch?v=wulHes6Dm9E. The 50 mm diameter cup features evenly spaced ridges every 5 mm along its surface, making it easy to fill the water to the correct level. Two or three ridges down from the top (10-15 mm) is the preferred filling point. The gaskets can be cut from a sheet of rubber, neoprene, or similar hydrophobic materials with an outer diameter of 68mm and an inner diameter of 50mm. Alternatively, two gaskets can be printed in TPU or other flexible materials using this design. The screw lid features M70 x 1.5 threads that securely hold the sample film in place without requiring additional screws. I will conduct further tests with these cups over the next few days to determine if any modifications are necessary. For now, I am satisfied with their performance and functionality.