The difference between Rz and Rz3 Surface Roughness

I

Italian1022

Can anyone explain the difference between Rz and Rz3 surface roughness? I have a drawing with this requirement on it and I have an idea what it means, but it is just an idea. I need something more factual to present to my President.

Thanks for your help,
 
P

Phil Fields

I am not positive, the only thing I can come up with is 3 reprersents the Cut Off Value. See standards JIS B0601 (1994) & JIS B0031 (1994).
Phil
 
I

Italian1022

Thanks for your help Phil. I will research the JIS standards.:agree1:
 
J

JAltmann

Rz3 is the vertical mean from the third highest peak to the the third third lowest valley in a sample length over the evaulation length.

Rz is one of the worse parameters to deal with for correlation from equipment manuafacturer to equipment manufacturer. It has a long history of differnces in opinion of how it should be calculated. Some use the extreme peak to valley, some use a 10-point average (RzISO).

It is a very useful parameter, but just be aware of potenial differnces between you and customer's results.
 

Miner

Forum Moderator
Leader
Admin
Rz3 is the vertical mean from the third highest peak to the the third third lowest valley in a sample length over the evaulation length.

Rz is one of the worse parameters to deal with for correlation from equipment manuafacturer to equipment manufacturer. It has a long history of differnces in opinion of how it should be calculated. Some use the extreme peak to valley, some use a 10-point average (RzISO).

It is a very useful parameter, but just be aware of potenial differnces between you and customer's results.

JAltmann is correct. See page 5 of Explanation of Surface Characteristics. BTW, it is R3z, not Rz3.
 
J

JAltmann

Great link Miner, another good piece to add to my collection of surface finish information.:)
 
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