Reflective materials as well - i.e.: a polished stainless steel knife blade?

Continuing the discussion from Etching Stainless Steel or Titanium?:

I am interested to hear the answer for this question as well, I do Jewelry so I use silver and would love to engrave my work.

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Here is something about this:

There was also a topic about stainless steel, unfortunately I couldn’t find it quickly. In short: you can’t cut stainless steel but if that is treated with special compound/liquid you can engrave it (there were a short video about it to external web site). Maybe someone can link it in here.

EDIT: Here is the what that I was looking about:


and here is the post; where was the video about it:

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The compound that you need for some metals is e.g. “Cermark”.

There is a common misconception going around about engraving vs. marking. Engraving is a subtractive technique…you’re actually removing material by cutting a groove. You absolutely can’t do that in metals with a 40W CO2 laser cutter. You can mark the metals using something like Cermark/Thermark, which leaves a permanent black mark on the surface.

The GF team should clarify this by removing any reference to “engraving” in metals. It’s misleading and seems to be confusing a lot of people.

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Agreed - I’m interested in ‘marking’ (logos, text/numbers, ruled lines) on Stainless (polished and brushed).

…and also interested in how the less expensive MolyD approach looks/works v.s the industrial grade Cermark/Thermark.

To clarify the original question, though - I was concerned that a reflective surface (polished stainless) could damage the optics.

The laser loses power rapidly as it defocuses. With a 40W laser you shouldn’t need to worry about reflection damaging your optics…especially the focus lens, which is closest to the cutting area). At >100W of power heating and breaking your lens or the housing can be an issue.

Does this mean we also won’t be able to truly engrave even in things like brass, copper, or aluminum? I thought they were saying steel was right out, but those softer metals might allow for some material removal with the laser.

Not possible. You can remove surface treatments like anodizing or paint but you can’t engrave. An unfortunate bit of misleading marketing.

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But what about the videos showing macbook pro’s being engraved? Is that really a different technique?

No, but MacBooks are anodized aluminum - you’re basically ablating away the microns-thick layer of aluminum oxide on the surface of the metal.

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I am also very interested in seeing a molyD vs. cermark side-by-side marking comparison.
@fablab_elpaso you seem to have access to lasers and have been pretty vocal in these forums. Your thoughts? Or better yet, photos from actual tests that you may have done?

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