Need a Fiber Guru, Stainless warping issues

[Scott Anders]

I've had my 30 watt Bodor galvo fiber for about 2 months now and my main material I'm marking (annealing) is around 1mm Stainless. I'm having an incredible struggle with warping on this and thinner stainless. I know people are able to get it to mark a nice black mark without problems and relatively quickly as well. I've tried everything from out of focus, all 3 lenses I have (100,200 and 300mm) speeds, power, frequencies, hatch spacings, passes etc. I've come close with the 300mm lens, 4 pass, 1200 speed, 45% power, 150 frequency, .05 wobble with a .1 spacing and for hatching i'm using the snake type with three different hatches all around 0.07 45,315 and 90 degrees. I'm trying to keep the heat out but mark as well.

Admittedly the ones I'm having most problems with are bold graphics and text with quite a lot of surface area but i've seen it done and i'm hoping someone can share their best kept secret with me. I'm not new to lasers (16 years in the industry) but this fiber and lack of available written information from the manufacturer has me stumped..

Thanks in advance for any advice given.

[Dave Sheldrake]

Check the grade of the stainless, it's rolled and has stresses in the surface...hit one side and the bi metallic strip action will happen

[Kev Williams]

this may sound too simple, but it works...

Place the plate on a wet shop rag...

[Scott Anders]

Unbelievable!!!!! I don't understand the science yet of why that just worked but it did. Kev, you're a legend, if you're ever in Australia call in for a beer. Thank you so much

[Kev Williams]

Simple matter of the water absorbing the heat before it has a chance to warp the plate!

[Scott Anders]

Thanks Kev, words can't relay what I'm feeling right now. I've been filled with dread since the machine arrived thinking I should have just stuck to cermark on the trotec. Now the tables have turned, I was resigned to the thought I'd be switching every plate in the shop up to the next thickness of stainless.

[Ross Moshinsky]

If you want to get fancy, you could build a liquid cooled work surface which would be a more permanent solution. It wouldn't be all that complicated.

[Scott Anders]

Yes Ross, My mind is racing with ideas now, but I think the wet rag will get me by for the next few months. I was originally thinking the other way of using a heating element under the plate to keep a fairly uniform heat throughout. I like the wet rag and cooling better.