: After a set number of flexes, the leather is checked for signs of damage like tiny cracks or finish separation. Variations
You may be looking for one of these:
: In manufacturing and industrial settings, where equipment reliability is critical. astm d61821 pdf
It looks like you’re looking for the standard (not "D61821" — that number doesn’t exist; ASTM standards typically have a hyphen then the year, like D6182-21). : After a set number of flexes, the
: The results are interpreted based on the established limits for sediment content, which may vary depending on the application and the equipment manufacturer's specifications. which acts as a plasticizer
Polyamides (nylons) are hygroscopic. They absorb moisture from the air, which acts as a plasticizer, lowering tensile strength but increasing flexibility.