Deep Engraving of Stainless Steel Rings

[marc craig]

Hello,
I am shopping for a fiber laser that can engrave alpha-numeric characters in 304 SS rings (OD 1.25" with .060" wall thickness). I like the look of deep engraving since it best matches the hand stamping (and filling with lacquer) that I have been doing. My cramped hands need a break. By deep I mean deep enough to see some depth so probably at least .010" to .025". I am assuming I can get a nice black cutout area so no more lacquer will be required.

I am thinking a fiber laser with rotary axis. This is low volume 1 offs so burn time is not critical. Does anyone have any suggestions on specific laser type and/or a laser vendor that you have had good luck with?

All advice will be greatly appreciated as the selection of laser makers both domestic and overseas is a little overwhelming.

Thank you!

[AL Ursich]

Just a suggestion, ask here who could do this project like this for you. Be sure the Fiber can actually give you the results you are needing. Then invest the big money...

[Kev Williams]

As to 'deep enough to see'--- it may surprise you how little the depth needs to be--
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-I made this plate to show customers who routinely ask for 20-30 thousandths deep engraving. Most injection mold engraving is no more than .008", and any engraving that needs paint filled I run at .006"...

as to 'deep and dark'-- in my experience: 'annealing', which is lasering at low power, very slowly with a very tight hatch and specific freq settings, oxidizes the carbon at the surface of the metal, darkening it. However, it takes on a holographic look, changing darkness as the viewing angle changes. In most cases there's no ablating at all so no depth. Many of my customers really like the look.

me, I like a LITTLE depth, like I got with this knife blade... this came out near perfect, but I've found this is the exception, not the rule :)
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--to get this required a little more power and a frequency setting that just started to remove metal...

finally, if you want deeper than this, the compromise will be in the darkness-- I've found that enough power to engrave deep compromises the ability to anneal to black afterward. My guess is that the extra heat is the cause. You can still get dark, but more brown than black.

Last week I lasered a bunch of basic zinc plated bolt washers some high school kids were going to make into necklaces. I used a tight hatch, slow but high power and mid-frequency settings, one pass- the result was about a medium-dark brown mark about as deep as my knife blade above. They loved them :)

You could probably get by with a basic 20-30 watt galvo fiber with a rotary, available from many China companies direct, or from US companies for roughly a 60% price bump. I would go 30w, I'm glad I did...

[John Lifer]

I would second Kevin, but I'd say that if you can afford it, go for a 30 watt. I've a 20 and would love the extra power sometimes.....