Technical commercial molding; used for general consumer goods made from standard commodities (e.g., ABS, PC/ABS blends). Medium / Baseline
The International Organization for Standardization established (which superseded the older DIN 16742 standard) to create a unified global framework for tolerancing molded plastic parts. What is ISO 20457? iso 20457 tolerance table pdf
In North America, the SPI tolerance system—using letter-number grades such as A1 (commercial) through B3 (fine)—remains common. SPI tolerances are expressed as a base tolerance plus an increment per inch of dimension. A B1 tolerance on a 2-inch PP dimension yields approximately ±0.010 inches (0.254 mm). Many Chinese manufacturers familiar with European standards can map SPI specifications to ISO 20457 grades. To avoid misunderstandings when sourcing from offshore suppliers, specify ISO 20457 TG grades directly rather than relying on SPI conversion. Where to Find PDF Documents:
Concise recommendation
To implement this standard, it is recommended to download a formal PDF document. Where to Find PDF Documents: In North America