Iso 20457 Tolerance Table Pdf -

If your general tolerance block references "ISO 20457 – m", you do not need to write individual tolerances on every dimension. The machinist knows to adhere to the Medium tolerance table.

Note: This table represents general dimensional tolerances. For exact allocations based on specific compound shrinkage rates and tool-bound vs. non-tool-bound dimensions, please reference the official ISO 20457 PDF framework. 5. Tool-Bound vs. Non-Tool-Bound Dimensions

The heart of the ISO 20457 tolerance system is its classification into . The standard defines nine tolerance grades, ranging from TG1 (very precise) to TG9 (very coarse). The appropriate tolerance grade depends on the part’s functional requirements, material properties, and manufacturing process capabilities. iso 20457 tolerance table pdf

📐 Tolerance Class TG6: The Most Common Injection Molding Standard TOLERANCES

For engineers, quality managers, and procurement professionals working with injection-molded plastic parts, precision is everything. However, the properties of plastics—from material shrinkage to thermal expansion—make them fundamentally different from machined metals. Applying metal tolerances to plastic parts inevitably leads to costly rework, rejected shipments, and strained supplier relationships. This is where comes into play. If your general tolerance block references "ISO 20457

Several industry sources confirm these general assignments. ISO 20457 TG4 is typically applied for precision injection molded parts such as gears, TG5 for housing parts, and TG6 for packaging components. In the automotive industry, critical components typically require TG4 or higher, with deviations measured in micrometers.

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. For exact allocations based on specific compound shrinkage

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.

ISO 20457 is the direct international successor to the German national standard DIN 16901, and the two are closely related. However, there are key differences:

While ISO 9908 outlines the general design and performance requirements, ISO 20457 gets into the granular details of the physical dimensions. It defines the permissible deviations from the nominal dimensions for various pump parts, such as impellers, shafts, housings, and seals.

and precision classes to define allowable deviations. A critical requirement is that a callout must include the grade and environmental conditioning (e.g., ISO 20457–TG6 + 23°C/50%RH ) to be enforceable. Super-Ingenuity Tolerance Categories (Materials)