| Symbol | Ra |
|---|---|
| Unit | µm |
| Attribute-ID | arithm avg roughness flank R_a |
| Numeric ID | 391 |
| Value Type | PMTechValue |
The surface roughness of the flank influences the flank load carrying capacity and scuffing load capacity. Alternatively, the arithmetical mean roughness value Ra or the mean roughness depth Rz can be specified.
Internally, the program uses the mean roughness depth. The approximation from DIN 3991 is used to convert from the arithmetical mean roughness value: Rz = 6 Ra.
If the roughness is not specified, the default value of Rz = 20 μm is used for the flank and root, which applies as an approximation for coarsely milled teeth.
See flank arithmetical mean roughness value (cylindrical gear load carrying capacity)