Recommened Evaluation Method for Flatness

[[Ty...]]

What is everybody's recommended Evaluation Method for Flatness? The program I am running now was set up as Minimum feature and I'm getting a result of 0.06mm. If I change that to LSQ, my reading jumps to 0.09mm.

I think I understand why they are different, but I didn't expect a 50% jump and thought it would measure better. Just wondering what everybody else uses and why?

In case it matters, this is a Flatness Ref with a Zone Size of 100x100.

[[Me...]]

Use Minimum Feature (Minimum Zone).

"Minimum-Zone fit yields a lower (or equal) peak-to-valley distance of the residuals and can be a better indicator of form, particularly if the data points are “good”, meaning fairly dense, with no outliers, and not much affected by measurement noise"

[[Da...]]

Are you using evaluation and speed from the cookbook ?

It should be speed 3mm/s with 3mm probe. and step width 0.31/ factor for outlier 3.0 / adjacent points 5 / No. of iterations 1 / wavelength 10mm / Filter 2.5

I am using LSQ

[[Er...]]

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is a very brave statement. It all comes down to the surface properties of that unique surface. Is it polished, milled, turned. Ra, Rz or Rp limitations? Or any surface requirements?

The cookbook is a merely a starting point, not the final solution.

[[Ri...]]

All form measurements should use Minimum Zone which is the default when you create the characteristic.

[[He...]]

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And thank god for that. I always gets very nervous when Germans speak of the "final solution".

[[Er...]]

Hehe yeah.. I actually chosed those words to see if anyone would react, and you sir, you never dissapont me. Not to spin away from the topic, but I scrolled through the presentation of 100 years of metrology. Seems like no innovations beween1926 to 1953, sounds highly unlikely, like nothing happend at all. 😱