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: Offers downloadable quality and tolerance templates, including Excel-based CTQ (Critical to Quality) feature tables and 2D note blocks for ISO 20457-TG6. Understanding the Tolerance Groups (TG)
The standard, which replaced DIN 16742, defines the tolerances and acceptance conditions for plastic molded parts. It uses Tolerance Groups (TG) to classify accuracy based on material properties and manufacturing processes. Key Tolerance Group: TG6
A new draft revision, , is currently under development. While the core principles remain unchanged, manufacturers and engineers should monitor the ISO/TC 61/SC 11 committee for updates. The second edition is expected to maintain compatibility with the 2018 version while incorporating clarifications and refinements based on industry feedback. iso 20457 tolerance table pdf
These tolerances apply directly to the dimensions determined by the physical mold cavity. Series W is further split into two sub-categories: Tool-Dependent Dimensions ( WAcap W sub cap A
Note: These are illustrative values — always refer to the full standard for critical applications. Key Tolerance Group: TG6 A new draft revision,
For general thermoplastics, the standard typically defaults to unless otherwise specified.
Note: Actual values in the official standard vary by material (e.g., glass-filled, amorphous, crystalline). The above is an illustrative summary. These tolerances apply directly to the dimensions determined
for part sizes based on manufacturing effort and tooling.
The is more than a grid of numbers; it is a strategic tool for balancing cost and quality. By understanding the three tolerance classes (Fine, Medium, Coarse) and knowing how to navigate the linear and angular tables, you can produce drawings that are both professional and manufacturable.
Many engineering firms do exactly this for their quality departments.
The is not just a chart of numbers – it is a philosophy of realistic tolerance allocation for plastics. By adopting this standard, you will reduce tooling costs, lower inspection fallout, and improve assembly reliability.