Iso 20457 Tg5 Extra Quality -

of non-porous thermoplastics, thermoplastic elastomers (TPEs), and thermosets.

Historically, engineers erroneously applied metal-machining tolerance standards like ISO 2768 to molded plastic parts. However, unlike isotropic metals, polymers experience dramatic processing shrinkage (0.5% to 2.5%), thermal expansion, moisture absorption, and post-molding warpage. Iso 20457 Tg5

: The final size of a part depends heavily on its shrinkage rate. TG5 accounts for standard fluctuations in shrinkage during the cooling process. of non-porous thermoplastics

ISO 20457 (which superseded the older German standard DIN 16742) is the global benchmark for geometric tolerances in plastic molding. Unlike metals, plastics undergo significant and sometimes unpredictable volumetric shrinkage as they cool from a molten state to a solid. thermoplastic elastomers (TPEs)