Iso 20457 Tolerance Table Pdf Jun 2026

While ISO 9908 outlines the general design and performance requirements, ISO 20457 gets into the granular details of the physical dimensions. It defines the permissible deviations from the nominal dimensions for various pump parts, such as impellers, shafts, housings, and seals.

The table cross-references nominal size ranges (e.g., 0.5–3 mm, 3–6 mm, up to 4000 mm) against the three tolerance classes: Fine (f), Medium (m), and Coarse (c).

The most sought-after component of this standard is the . Typically, the PDF version of ISO 20457 contains several critical tables, but one stands out: the table linking nominal sizes to permissible deviations for linear dimensions and angles.

The global reference standard specifies the geometrical and dimensional tolerances and acceptance conditions for non-porous plastic molded parts. Officially introduced to replace the older German standard DIN 16742 , the ISO 20457:2018 Standard provides engineers, molders, and quality control professionals with a unified framework to manage the unique shrinkage, warpage, and thermal properties of molded polymers. Applying metal-machining tolerance standards like ISO 2768 directly to plastics often results in unachievable constraints and over-inflated production costs. Understanding the ISO 20457 Tolerance Groups iso 20457 tolerance table pdf

The standard applies to non-porous molded parts made from thermoplastics, thermoplastic elastomers, and thermosets. If agreed upon by contractual parties, the standard can also be applied to other plastic processes.

Disclaimer: This post is for informational purposes. Always consult the latest official ISO standard for legal and quality-critical applications.

Specifying tools like a CMM (Coordinate Measuring Machine) or Optical Measurement Systems. While ISO 9908 outlines the general design and

ISO 20457 (full title: “Plastics moulded parts — Tolerances and acceptance conditions”) specifies possible manufacturing tolerances for plastic molded parts. First published in 2018, this standard replaced national standards such as Germany’s DIN 16742, bringing a unified global framework for plastic part tolerancing. The standard applies to all integral features with general tolerances, using a surface profile tolerance within a specified datum system, and allows for additional specifications when functional needs require tighter control.

Purchase the full ISO 20457:2018 from the International Organization for Standardization .

A true “tolerance table” in ISO 20457 depends on: The most sought-after component of this standard is the

If tolerances are too loose, parts may not fit or perform as designed.

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.

The tolerances vary depending on the material, as different plastics shrink and mold differently. The standard generally divides materials into groups: