Strength Tester #1

thingiverse

This test piece was inspired by Thomas Sanladerer's fascinating video on material strength variations. Building anything with a 3D printer requires an understanding of the material properties to create structural components. This tool determines the tensile and potential compressive strength of 3D printed materials. Print this piece in your preferred material, then thread a drill bit or hex wrench through one end (attach it to a vice) as shown in the images. Use the hole at the other end to add weights and apply force. The nominal cross-sectional area is 10 x 10mm or 100mm^2 (in imperial units, this is 0.155 square inches). By dividing the applied pounds of force by 0.155, you can calculate the PSI or pounds per square inch. Measurements will be "nominal" as most 3D printers lack accuracy. In my test, one side was measured at 9.93mm while the other at 10.15mm, making the area approximately 2% larger than expected, roughly 0.158 square inches in reality. To increase precision, use a caliper to measure exact numbers. This design prints vertically and horizontally because layer-by-layer deposition favors horizontal runs over layered prints from a tensile strength perspective. When printing without rafts, identify and mark both vertical and horizontal sides so you can test the 'vertical' and 'horizontal' printed tensile strengths individually. Finally, infill has a considerable impact here - higher infill amounts result in increased plastic distribution across the cross-sectional area while lower infill reduces this effect. In reality, it's the total amount of plastic (including homogeneity) that determines how strong or crushable the component will be under tension and compression respectively.