Visual Difference in Surface Finish

[Jaq]

Hi all,

I am trying to determine a cutoff for the life of an abrasive belt based upon the surface finish it leaves. Does anyone have any experience of a range of surface Ra in a specification, or know what differences in Ra are easily visually distinguishable?

Many thanks in advance,
Jaq

 

[grinderguy]

The finish generally gets finer as the belt wears. I use stock removeal and temp. to determine when to change the belt. The surface comparator standards in books like MSC's can give you a visual. This is very hard to specify or communicate. If I were making the part and I do make parts using belts, I would measure the temp of the part with an electronic therometer. When the abrasive is not cutting the part heats up. A free cutting belt has a much lower temp and the part asorbs less heat so a lower temp reading.
Bob 502-452-9851

Robert Setree

http://www.advanced-grinding.com