Can anyone help me in interpreting this surface finish symbol?

[ParthZala]

I have this surface finish on a manual. Nothing specific about unit of anything is given. What should I interpret it?

thanks in advance.

 

[3DDave]

https://www.finishing.com/448/48.shtml

"Rz is the sum of maximum peak and maximum valley of a profile, while Rmax is only the value of maximum peak of the profile."

https://www.mitutoyo.com/wp-content/uploads/2012/11/1984_Surf_Roughness_PG.pdf

 

[dgallup]

Assuming this is an inch drawing, the units are micro-inches. If it is a metric drawing the units are micro-meters. 4 micro-inches is a reasonable value for a ground surface, 4 microns is not.

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The Help for this program was created in Windows Help format, which depends on a feature that isn't included in this version of Windows.

 

[ParthZala]

Thank you 3DDave and dgallup for answers.

[tt]"Rz is the sum of maximum peak and maximum valley of a profile, while Rmax is only the value of maximum peak of the profile."[/tt]

In the surface quality test, there are two lengths for measuring, sampling length and evaluation length. Rz is an average of highest picks and valleys of each sampling length while Rmax is the height from Highest pick to the lowest valley on evaluation length. This is what I believe, please correct me if I am understanding it in the wrong way.

[tt]"Assuming this is an inch drawing, the units are micro-inches. If it is a metric drawing the units are micro-meters. 4 micro-inches is a reasonable value for a ground surface, 4 microns is not."[/tt]

Yes, that's what I am thinking, but 4 microinch becomes 0.1 microns. That is, I believe, way too smooth surface and achieving that quality will be a costly matter. What do you think?

This surface is not a sliding surface.