Iso 20457 Tolerance Table Pdf

ISO 20457 ("Plastics — Tolerances for moulded parts") defines the permissible deviations for dimensions, shapes, and positions for plastic injection molded components. Key aspects of this standard include:

ISO 20457 is the direct international successor to the German national standard DIN 16901, and the two are closely related. However, there are key differences:

The standard acknowledges that plastics are viscoelastic. Their final dimensions depend on: iso 20457 tolerance table pdf

Angles are treated differently because the deviation is measured as a length over a given length (mm/m) or directly in degrees/minutes.

Unlike metal parts, plastic tolerances must account for processing shrinkage, tool binding, and material properties. Geometrical Tolerancing: ISO 20457 ("Plastics — Tolerances for moulded parts")

For each dimension on your drawing, determine whether it is:

China’s GB/T 14486 aligns closely with ISO 20457. The Chinese standard uses a similar approach with material shrinkage categories (MT1 through MT7) and tolerance grades A (precision), B (standard), and C (coarse). This alignment facilitates international trade and ensures that parts designed to ISO 20457 can be manufactured in China using the GB/T 14486 framework. Their final dimensions depend on: Angles are treated

Several industry sources confirm these general assignments. ISO 20457 TG4 is typically applied for precision injection molded parts such as gears, TG5 for housing parts, and TG6 for packaging components. In the automotive industry, critical components typically require TG4 or higher, with deviations measured in micrometers.

Note: This table is for illustrative purposes. Always cross-reference official ISO documents for production-level calculations. Tooling vs. Molding Tolerances