Insert Surface Finish Symbol¶
In one sentence: Places an ISO 1302 surface texture / roughness symbol on a view with Ra value, lay direction, and machining requirement.
Overview¶
Workbench: TechDraw
Menu: TechDraw → Symbols → Insert Surface Finish Symbol
The symbol consists of the standard check-mark (√) with lines indicating machining status, Ra roughness value, optional lay direction, and optional machining allowance.
Step-by-step¶
- Select a view.
- Choose TechDraw → Symbols → Insert Surface Finish Symbol.
- In the task panel, fill in:
| Field | Description |
|---|---|
| Ra | Roughness average (e.g. 1.6, 3.2, 6.3 μm) |
| Symbol Type | Basic / Machining required / No machining |
| Lay Direction | = // ⊥ × M C R |
| Method | Manufacturing method note |
| Machining Allowance | Stock to remove (mm) |
| Sampling Length | Sampling length for Ra measurement |
- Click OK. Position on a face edge or with a leader.
Ra standard values (ISO 1302)¶
| Ra (μm) | Typical process |
|---|---|
| 50 | Sand casting, rough cutting |
| 12.5 | Rough turning / milling |
| 6.3 | Normal turning / milling |
| 3.2 | Fine turning / milling |
| 1.6 | Grinding |
| 0.8 | Fine grinding |
| 0.4 | Honing / lapping |
Common mistakes and pitfalls¶
Ra values are not enforced
FreeCAD accepts any numeric value for Ra — there is no enforcement of ISO preferred values. Always choose from the ISO 1302 preferred Ra series unless your standard explicitly uses non-standard values.
See also¶
- Insert Welding Symbol — welding annotation
- Insert Hole / Shaft Fit — ISO tolerance fit annotation
- TechDraw Workbench — workbench overview