Technical product documentation. Representation of splines and serrations
1Key Takeaways
This document specifies the rules and graphic symbols for the representation of splines and serrations in technical product documentation. Splines and serrations on detail and assembly drawings are represented in full display (all details are in actual size) and simplified representation.
2Expert Interpretation
An in-depth analysis of BS EN ISO 6413:2018, the standard for the representation of splines and serrations in technical product documentation, covers both complete and simplified diagramming methods, graphical symbol standards, assembly drawing rules, and major technical changes from the 1995 edition. This standard applies to the standardized drawing requirements of mechanical transmission components.
Analysis of the core content of the standard
| Technical elements | Complete representation | Simplified representation |
|---|---|---|
| Line type | All line types of ISO 128-24 | 01.1 Thin solid line (tooth root)/04.1 Dotted line (pitch circle) |
| Tooth profile expression | True size of full tooth profile | Virtual cylinder + key feature line |
| Marking requirements | Optional | Must have additional graphic symbols |
Key Technology Evolution
Main changes in the 2018 version compared to the 1995 version:
- Standard name extension: Changed from "Technical Drawing" to "Technical Product Documentation"
- New introductory chapter: Clarifies the engineering value of simplified representation
- Graphic symbol standardization: Appendix A specifies the symbol scale size (h=3.5-20mm)
Typical Application Examples
When dimensioning involute spline shafts:
- Use 04.1 line type to draw the pitch circle diameter
- Add the graphic symbol shown in Figure 2 next to the feature contour line
- Associate parameter tables (module/pressure angle, etc.) through leaders
Implementation Suggestions
Note during the design phase:
- Preferably use simplified representations (Chapter 6) to improve drawing efficiency
- Shaft/hub parameters must be combined in assembly drawings (Figures 13-14)
- Tooth surface roughness annotations use a shared leader method (Figure 11)
This standard, together with ISO 4156-1 (involute splines) and ISO 14 (straight-side splines), forms a complete technical system.