: Engineering drawings often include the note: General tolerances ISO 20457 – TG6 . ISO 20457 Tolerance Table Overview
Post-molding shrinkage, storage conditions, environmental aging, and the assembly of multiple components. iso 20457 tolerance table pdf
| 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 | : Engineering drawings often include the note: General
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The appropriate TG depends on the specific plastic material used, its filler content, and the precision capabilities of the molding process. Tolerance Grade Process and Material Capability Cost Impact
You can find detailed summaries and excerpts of the tolerance tables in the following resources: Engineering Guides PolTolerances Guide
A true “tolerance table” in ISO 20457 depends on: