Match your nominal part dimensions to the correct row and column in the ISO 20457 table.
To implement this standard, it is recommended to download a formal PDF document. Where to Find PDF Documents:
is the current international standard for determining manufacturing tolerances of plastic molded parts . It replaces older standards like ISO 8062 and is closely aligned with the German DIN 16742. This standard is vital for designers and manufacturers to agree on achievable precision without driving up costs through unnecessary accuracy requirements. Key Tolerance Groups (TG)
Because ISO 20457 is a classification standard, its tables do not provide the raw numbers for every single dimension (that is the job of ISO 286, ISO 2768, etc.). Instead, it provides a .
Wider tolerance bands are required due to potential warpage and shrinkage variations. Comparison with ISO 286 The standard correlates its Tolerance Groups (TG) International Tolerance (IT) grades defined in iso 20457 tolerance table pdf
Technical commercial molding; used for general consumer goods made from standard commodities (e.g., ABS, PC/ABS blends). Medium / Baseline
: For a more visual breakdown of the material categories and tolerance groups, Online Documentation on understanding plastic part tolerances. OKW Gehäusesysteme TOLERANCES
When to consult the PDF/standard directly
: An official abstract and sample pages of the ISO 20457:2018 Standard . Match your nominal part dimensions to the correct
Amorphous plastics (e.g., ABS, PC) generally exhibit lower and more predictable shrinkage than semi-crystalline plastics (e.g., POM, PA66).
High-shrinkage raw polymers or flexible elastomeric components. The Structure of the ISO 20457 Tolerance Table
ISO 20457 uses to define the achievable accuracy based on the manufacturing process and material properties.
Classifies materials based on their shrinkage behavior (e.g., crystalline, amorphous, reinforced). It replaces older standards like ISO 8062 and
Because ISO 20457 is a copyrighted document published by the International Organization for Standardization, the full PDF cannot be downloaded for free. It must be purchased from an authorized standards distributor. However, accessing the tolerance tables and the document itself is straightforward.
The PDF of this standard, particularly its essential tolerance tables, is more than just a document—it is a quality assurance tool that:
The standard establishes the international framework for manufacturing tolerances and acceptance conditions of non-porous plastic molded parts . It officially replaces the older German standard DIN 16742 . Accessing a certified ISO 20457 Tolerance Table PDF ensures that engineers, toolmakers, and quality managers use accurate, technically feasible dimensional and geometrical parameters. This prevents over-specification, which reduces tooling costs and manufacturing waste. Why Plastics Need a Unique Tolerance Standard