What the standard defines
A durometer test: a specified indenter pressed into a flat specimen under a defined force, with the depth read on a scale. Different scales — A for softer materials, D for harder ones — use different indenters and forces. The standards set the instrument, the specimen and the procedure.
What it does not promise
No printed-part stiffness: infill, wall count and geometry change how flexible a print is. No printability: softer grades need slow speeds and constrained extruders. No abrasion, tear or temperature resistance, which are separate properties. No comparability across scales without the scale letter.
What it works with
The extruder type and recommended speed the filament maker publishes, since hardness decides how easily the filament buckles. Diameter tolerance and drying advice, which matter more with flexible materials.
Questions makers ask before buying
Is a lower Shore number softer?
Yes, on the same scale. A lower Shore A figure is a softer, more flexible material, and softer grades are generally harder to print.
Can Shore A and Shore D values be compared directly?
No. They use different indenters and forces for different hardness ranges, and a value on one scale is not simply converted to the other.
Last reviewed 15 September 2026