Tight Flatness Condition

[rsm7400]

I am having an increased need for tighter flatness specs. Currently I have quite a few parts that are within 50 millionths flatness. I have been able to successfully measure these with an optical flat, but only when the surface finish is really good.

I have a new part coming that needs to be flat within 33 millionths. It will once again be hard to measure because of the polish we are able to produce here on this grade of material isnt as reflective as others. Has anyone found a nice system that is easier to read than an optical flat and cheaper than an interferometer?

________________________________
Ryan M
Quality Engineer
3d Printer Hobbyist

 

[BillPSU]

I've lapped hydraulic pump/motor end caps to 35 millionth flatness and always used an optical flat.
I haven't heard of a better way to measure flatness in this range.

Bill

 

[KENAT]

I believe at least some surface profilometers will be able to measure the flatness you mention however, not sure they fit into your cost requirement.

Posting guidelines faq731-376

http://eng-tips.com/market.cfm?

(probably not aimed specifically at you)
What is Engineering anyway: faq1088-1484​

 

[dgallup]

Our Perthen surface profilometer measures to 0.1 micron but that may not really be good enough since it's not quite 10% of your spec.

----------------------------------------

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.

 

[KENAT]

An AFM would certainly do it but the size of area measured and cost to do so would be an issue.

Posting guidelines faq731-376

http://eng-tips.com/market.cfm?

(probably not aimed specifically at you)
What is Engineering anyway: faq1088-1484​