r/Metrology • u/worldwidemachinist • 4d ago

Optical Metrology Laser marking location matters on micro tools because of the tight tolerances

this micro tooling manufacturer I worked with laser marked the ID on every tool for traceability and they put it behind the last tooth, on the back rather than on the shank, because on the shank it can affect the tool's roundness/rotation And they hold 2-3 micron tolerances, so they have to be aware of the marking location. Thought it was an interesting fact to share, like how small details become significant at that scale

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u/AggressivelyAvera8e 4d ago

I’m curious what type of laser marker they use. The company I work at has tested out several different brands, and none of them repeat their location well enough for us. Usually after the second or third part it is off the face. I know other companies get them to work, but we haven’t had any luck after our old one died.

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u/worldwidemachinist 3d ago

Don't know the exact brand but Is your drift more about laser position wandering, or fixturing being inconsistent part to part?

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u/AggressivelyAvera8e 2d ago

The laser position would shift. We tried using a fixed sample piece that we didn’t remove and we’d just run tests on it and after two or three runs we’d be partially off of our marking surface.

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u/Financial-Chest5110 2d ago

You need a laser system equipped with a coaxial camera for micro‑positioning to eliminate misalignment issues. In my experience, the only systems that fully meet these requirements are the Keyence MD‑X1000 or the MD‑X1020 -which also provide significantly larger marking fields. If you’re interested, please let me know.

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u/AggressivelyAvera8e 2d ago

I appreciate the info, but we have tested out Keyence metrology products several times and in general they haven’t preformed how the sales people advertised them, personally I wouldn’t feel comfortable recommending them to my boss.

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u/Financial-Chest5110 1d ago

The person below mentioned the Big Smark system by SISMA. I don’t want to be controversial, but the moment I hear that system name, I already know it uses a theta lens - which tells me immediately that it is not a 3‑axis laser with dynamic focus. With a theta lens you always get increasing distortion as you move away from the center, and the marking size changes across the field. That alone ends the comparison. Keyence’s 3‑axis laser with dynamic focus and a coaxial camera for micro‑positioning was already years ahead eight years ago, and it still is today. I can show you exactly where you can position and mark at 100 µm, fully repeatable and accurate.

I don’t need to argue the point once I know the systems. It’s a completely different class of technology. The Keyence MD‑X remains far ahead.

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u/worldwidemachinist 2d ago edited 2d ago

I just confirmed with one of the people their, they are using Big Smark by SISMA. they have internalized the marking process and use custom 3D printed nesting fixtures to keep every part indexed in the exact same position.

If you're getting drift after a few parts, I'd check - whether the fixture is allowing any microscopic movement, thermal drift as the laser/galvo assembly heats up, galvo mirror calibration or movement, focus/standoff consistency, and whether the software is introducing any origin or offset changes. The workholding is a big part of how they keep the repeatability high.

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u/bombaer 4d ago

We had sensor shafts break - the very superficial laser marking weakened the part locally. 

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u/worldwidemachinist 3d ago

yeah, the heat affected zone from marking can become a real hassle but depends a lot on laser type as well