For general injection molding projects, DIN ISO 20457 TG5 is commonly applied as the default tolerance class when no specific tolerances are specified on the technical drawing.
Whether you are focusing on or quality control inspection .
The bridges this gap. It establishes standard tolerance blocks and surface profile criteria within a defined Geometrical Product Specification (GPS) datum framework. It helps stakeholders explicitly delineate between "general tolerances" (applied broadly to non-functional attributes) and "direct tolerances" (assigned to hyper-critical, tight-fit assembly dimensions). TOLERANCES
When you purchase the official ISO 20457:2018 PDF, the document should contain the following key sections: iso 20457 tolerance table pdf
Let’s walk through a real-world example to solidify your understanding of the .
| Nominal size (mm) | PT3 (Fine) | PT5 (Medium) | PT7 (Coarse) | |------------------|------------|--------------|---------------| | up to 10 | ±0.10 | ±0.25 | ±0.50 | | 10 – 25 | ±0.15 | ±0.35 | ±0.70 | | 25 – 63 | ±0.20 | ±0.45 | ±0.90 | | 63 – 100 | ±0.30 | ±0.60 | ±1.20 | | 100 – 160 | ±0.40 | ±0.80 | ±1.60 |
Below is a simplified conceptual example of how a tolerance table is structured for standard linear dimensions (expressed in millimeters): Nominal Dimension Range (mm) TG3 (Fine Precision) TG4 (Standard Precision) TG6 (General Production) TG8 (Coarse) Over 1 to 6 Over 6 to 30 Over 30 to 120 Over 120 to 400 For general injection molding projects, DIN ISO 20457
Specifying tools like a CMM (Coordinate Measuring Machine) or Optical Measurement Systems.
For practical use, one should obtain the official document from an authorized standards provider (e.g., ISO, ANSI, or national bodies like BSI or DIN). Many educational summaries and “cheat sheets” exist online, but only the official PDF contains the complete, legally authoritative tables. The tables in the standard are the final reference for any quality control dispute.
Your drawing must classify each dimension using ISO 20457’s three categories: It establishes standard tolerance blocks and surface profile
What (e.g., ABS, PA66, PC) you are currently using.
The standard defines nine , ranging from TG1 (the most precise/tightest) to TG9 (the coarsest/widest).
