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non-contact 3d surface roughness measurement 1

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minimotorsports

Mechanical
Joined
Jan 10, 2007
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US
I'm trying to find a company/lab to do some 3D surface roughness measurements for me. I'm looking for some specific parameters and having trouble finding someone who can measure what I need for a model that has been developed.

The tricky parameter is the standard deviation of peak distribution.

I have found several labs that use non-contact white light interferometers, but they do not know how to interpret the data to give me the standard deviation of peak distribution.

Can anyone give me any tips to find the standard deviation of peak distribution?
 
If you still interesting we can try to do it for you. But we must know exactly what do you want to obtain. My Email is zakiev@ukr.net. We can measure 3D topography of surface with the help of non-comtact interferometric profiler.
 
 http://www.eng-tips.com/threadminder.cfm?pid=367
minimotorsports,

Please believe me that I have done extremely similar work before, GW model, etc - I would not say exactly same. Anyway, I will just give you what I gained before:

1) You insist non-contact imaging, so the tapping mode of AFM can be used;
2) When you have 3-d surface topography from AFM, you have to do the calculation youself to find/define the peaks. 2 years ago, the AFM I was using does not support this calculation automatically.
3) Actually I think I wrote a program to calculate this offline before - find the peaks and fit into whatever distribution. It is not hard at all. I do not understand why the labs won't take this.
4) You have to be quick because I always wanted to write a paper on this, but have been lagging after I left school. Just kidding, if I pick it up again, it will be purely numerical as I have no more access to AFM.
 
The standard deviation of peak heights could certainly be calculated from 3D data sets. However, the challenging part is in the determination of "what defines a peak".

Is it any local maxima, regardless of its position? Then you would have to count a small bump in the bottom of a pit.

Is it only local maxima? Then you would not count a "ridge".

These topics are being wrestled in ISO TC213/WG 16 and some definitions are falling in place.

Try Digital Metrology Solutions ( to have something developed. Otherwise, Michigan Metrology ( could get raw, ASCII data to you and you can process it yourself.

Good luck!
 
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