Surface Rougness Cutoff Length

[weisusu]

To determine a cutoff length for surface roughness measurement, the idea is to exclude waviness in the surface roughness measurement. But, how can in determine what cutoff length to use?

Thanks

 

[BUTCHCWIQAM]

What are you meaning by "cutoff lengths"?
What type of instrument are you using for measurements?
Do you have control of the instrument to be able to control the travel over the surface, if so what are the increments of travel?
Thanks

 

[DennisP]

The general rule is for the cutoff length to be 1/6 of the length of trace. This is the value we use unless our customer specifies otherwise. It is also the default value used in most surface finish test devices.

 

[mecheng05]

For our metric inspectiong of surface finish, we use a default cutoff value of 0.8mm. Of course, if the drawing states the cutoff value, we use what is requested.