When engineers search for the "ISO 20457 tolerance table PDF," they are typically looking for specific dimensional data. While the full standard is a copyrighted document available for purchase through the ISO store or national standards bodies (like ANSI, DIN, or BSI), understanding the structure of these tables is crucial for those working with the document.
Most moulders can reliably hold PT2 for well-designed tools and stable materials. PT1 is only achievable with automated cells, hot runners, and 100% inspection.
| PT Grade | Description | Typical Application | |----------|-------------|----------------------| | PT1 | Very fine (high precision) | Medical devices, optical components, precision gears | | PT2 | Fine | Consumer electronics, automotive interior trim | | PT3 | Medium | Standard housings, toys, general purpose parts | | PT4 | Coarse | Large panels, containers, parts with thin walls | | PT5 | Very coarse | Very large mouldings (>1000 mm) or warpage-prone materials | | PT6 | Extremely coarse (no tolerance specified) | Reference only for design verification | | PT7 | Up to agreement | For contract-specific requirements |
View abbreviated versions or "Note Blocks" for drawings at Super Ingenuity .
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Imagine designing a gearbox. The gears inside require "Fine" tolerances, but the outer cast housing only needs "Coarse" tolerances. ISO 20457 provides a systematic way to assign these levels without over-specifying (which increases cost) or under-specifying (which causes assembly failure).
Angular tolerances are unique because the permissible deviation depends on the length of the shorter leg of the angle. The table provides deviations in degrees, minutes, or as a linear deviation per unit length (mm/m). A coarse tolerance for a 90° corner might permit ±1° for a very short leg, whereas the fine class could require ±0.5° or tighter.
The keyword **“iso 20457 tolerance table pdf”” is widely searched, but caution is required. Many websites offer “preview” tables that are incomplete or contain typographical errors. As of 2025, the official standard is copyrighted by ISO (Geneva) and national bodies like ANSI, BSI, DIN, and AFNOR.
