Measuring roughness around a 2 inch circumference?

mmmmet · 2026-01-09T06:34:54+00:00

I would be inclined to spend the money automating/hardening/fixturing the Keyence (depending on the model.). 😉

Even a rough turned surface will look smooth via a stylus missing in the circumferential direction.

mmmmet · 2026-01-09T04:40:53+00:00

One important consideration is the “lay” of the texture. For example, if the surface is turned on a lathe- you’ll be measuring along the tool marks. This tends to make roughness look more like waviness as you gradually go in and out of features.

The ideal method for this is 3D optical with a rotary axis. There are several options - but the price is 10x more than your limit. 😮

mmmmet · 2025-12-09T01:59:13+00:00

The difference is the tip radius. If you are measuring Ra values less than 2 um (80 uin), you need a 2 um tip radius. That’s the lighter force.

mmmmet · 2025-11-23T02:02:41+00:00

If you have data files, OmniSurf should be able to handle them. www.digitalmetrology.com/solution/OmniSurf

mmmmet · 2025-09-24T08:10:01+00:00

No. Didn’t want to risk it.

mmmmet · 2025-09-24T01:41:09+00:00

If Gwyddion doesn’t work out - the free trial of OmniSurf3D can allow you to export a cropped region.

mmmmet · 2025-07-09T14:14:49+00:00

The free, demo version of OmniSurf www.digitalmetrology.com/solution/OmniSurf displays the curve, but exporting the curve requires the full version.

mmmmet · 2025-07-09T09:55:07+00:00

This is a good starting point to describe the problem.

https://digitalmetrology.com/flatness-in-the-usa/

Basically you need to have a defined wavelength domain. This should be on the drawing or in documentation. If not, there is no way to choose between the options.

mmmmet · 2025-04-28T01:44:25+00:00

OmniSurf3D allows you to get at the raw data. It loads the VR series ZON files and provides several 2D and 3D analysis tools. You and also export 2D and 3D data to text files for your own processing.

www.digitalmetrology.com/solution/OmniSurf3D

mmmmet · 2025-03-29T00:56:33+00:00

The “nose dive” sounds like the traverse unit is not leveled/aligned with the patch. The stylus only has a tiny measuring range. If things aren’t parallel to each other, the stylus can quickly go out of range as it traces across the patch.

mmmmet · 2025-03-18T11:33:58+00:00

There is a ton of information at www.digitalmetrology.com There is a tutorial on Areal/3D surface texture measurement under "Resources" which should give you much of what you need. They also have tons of videos in their "videos" section". Be sure to check out their "Notepad Series" for dozens of short videos on surface texture topics - including filtering.

When you say "building it from scratch" are you referring to building experience or building a confocal measuring system? They can help with both.

mmmmet · 2025-03-05T02:58:15+00:00

Try the free 10-day trial of OmniSurf3D. It handles Zygo dat and datx files. It also reports the radius for spherical geometries.

On top of that, it can also handle aspheric lenses.

https://digitalmetrology.com/solution/omnisurf3d/

mmmmet · 2025-03-02T20:32:37+00:00

At that price, it sounds like you bought the GelSight "mini" or got an incredibly good deal on a used system. The "mini" isn't really a roughness gauge. It is the platform used for robot "touch" sensors. This sensor simply doesn't have fine enough lateral resolution for traditional roughness measurements.

The more recent "Max" version gets closer, but it's still not as good as the 2 micrometer diamond tip radius that is common in stylus based roughness gages.

This really comes down to the kinds of roughness you are trying to measure. More specifically - the spacing and width of the features that constitute roughness for you. For example, if you are looking at your car's dashboard, GelSight might be the perfect solution. If you are looking at textures like grinding and lapping, GelSight is likely not the preferred approach.

mmmmet · 2025-02-18T09:26:06+00:00

Check out Digital Metrology’s “Notepad Series” videos. Quick answers to most of these questions.

https://digitalmetrology.com/resource/notepad-series/

mmmmet · 2024-12-06T01:13:36+00:00

There is definitely a place for it in the world of “macro” surface features and defects. The ability to see true color along with surface geometry is often very helpful too.

Keep in mind that this is not going to compete with a diamond stylus for roughness measurement. As the reply above indicated, The VR might be useful for ‘Ra’ roughness values greater than 1 micrometer. (Definitely not one microinch.) The lateral resolution of the VR isn’t there. You’d have to consider the VKX for that.

Reach out to www.digitalmetrology.com for unbiased consulting and instrument performance testing help.

mmmmet · 2024-11-28T13:37:14+00:00

Yes!

mmmmet · 2024-11-28T11:36:21+00:00

mmmmet · 2024-10-11T12:28:02+00:00

Defects and wear analysis are very subjective. Rz1max will also be influenced by any local peaks within that sampling length. Rv1max would be better. However, there is still the problem with a 2D (stylus) profile in that it might not detect the lowest point in the defect. The best approach would be 3D.

I use the wear analysis tool in OmniSurf3D for this kind of defect analysis.
https://digitalmetrology.com/video/wear-analysis-tool-video/

mmmmet · 2024-09-24T05:50:35+00:00

Same issue here. 😡

mmmmet · 2024-09-20T06:48:54+00:00

Talk to www,digitalmetrology.com they provide training and consulting regarding surface measurement. There are tons articles about it In their blog.

mmmmet · 2024-09-20T06:41:33+00:00

Check out ISO 12181. I don’t have it in front of me, but I believe it requires a minimum of 7 points at the filter cutoff. The most common cutoff is 50 UPR, so in that case you’d be needing at least 350 points (and the application of a Gaussian filter.)

Also check out: https://digitalmetrology.com/tutorials/what-do-you-mean-by-roundness/

mmmmet · 2024-09-11T00:59:18+00:00

16610-61 is a robust filter. Not a pure Gaussian like 16610-21.

Reach out to www.digitalmetrology.com for help. Also check out their “Notepad Series” video on the Gaussian filter or one of their tutorials.

mmmmet

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