Iso 20457 Tolerance Table Pdf ~upd~ Jun 2026

The standard defines 10 Tolerance Groups, labeled .

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.

As the polymer cools, it crystallizes or solidifies, resulting in localized volumetric shrinkage. The extent of this variation depends on several critical factors:

One of the distinctive features of ISO 20457 is its use of surface profile tolerance within a specified datum system. This approach allows for comprehensive control over the entire surface form of the molded part, rather than piecemeal control of individual features. General tolerances are applied with surface profile tolerance linked to a defined datum reference frame, ensuring consistency across all integral features. iso 20457 tolerance table pdf

Tolerances that are too strict (e.g., trying to achieve TG3 on a complex, amorphous plastic part) can dramatically increase manufacturing costs by requiring more precise, expensive tooling and longer cycle times.

This article breaks down how to read an ISO 20457 tolerance table, the factors influencing these tolerances, and how to apply them to your PDF technical drawings. What is ISO 20457?

When Ana found the ISO 20457 tolerance table PDF among the archived engineering files, the room around her seemed to hush. The paper was older than she was, yellowed at the edges, its header stamped with a standard number that felt like a secret code. For three weeks she had hunted for a breakthrough: a way to rescue her small machine shop from the quiet decline that followed the factory orders shifting overseas. This faded table might be the key. The standard defines 10 Tolerance Groups, labeled

ISO 20457 uses to define the achievable accuracy based on the manufacturing process and material properties.

In mold design, the tolerance of mold molding dimensions should be controlled at . Precision molds adopt a smaller proportion (e.g., 1/5) to reserve margins for shrinkage fluctuation, mold wear, and process changes.

Here is a conceptual breakdown of what you will find inside the : As the polymer cools, it crystallizes or solidifies,

– Plastics — Tolerances for moulded parts – is an international standard that specifies a system of tolerances for the general dimensions of injection-moulded and compression-moulded plastic parts. It replaces the now-withdrawn national standards such as DIN 16901 (Germany) and provides a globally harmonized approach.

Compare this to ISO 286 for metal (IT7 grade for 100–200 mm: about ±0.035 mm). The plastic tolerance is nearly 10x wider. This illustrates the core lesson of ISO 20457: