Question on metal laser engravers

[Jim Good]

Can these metal laser engravers like Epilog's fiber lasers cut stainless steel sheets (2 or 3 mils thick) or only mark on them? Thanks!

Jim

[Neville Stewart]

I'm sure gantry lasers can, but my galvo will cut metal that thin.

[Gary Hair]

Since you'll likely need many passes to cut even very thin metal, a gantry is not really an option. It's too slow compared to a galvo.

[Keith Winter]

Since you'll likely need many passes to cut even very thin metal, a gantry is not really an option. It's too slow compared to a galvo.

+1 What Gary Said

[Rich Harman]

Since you'll likely need many passes to cut even very thin metal, a gantry is not really an option. It's too slow compared to a galvo.

With a CO₂ laser many fast passes are pretty much equal to one slow pass. What is different about a fiber laser that it can't cut deeper when moving slowly?

[Gary Hair]

With a CO₂ laser many fast passes are pretty much equal to one slow pass. What is different about a fiber laser that it can't cut deeper when moving slowly?

It's the same reason you can't take a pizza that should cook at 450 degrees for 30 minutes and use 900 degrees for 15 minutes - some things don't scale.

[Rich Harman]

It's the same reason you can't take a pizza that should cook at 450 degrees for 30 minutes and use 900 degrees for 15 minutes - some things don't scale.

Interesting answer. I asked what is different, since I know that a CO₂ laser is one of those things that do scale.

[Gary Hair]

Interesting answer. I asked what is different, since I know that a CO₂ laser is one of those things that do scale.

Running a job at 100% power and 100% speed is not the same as 50% power and 50% speed. By the same token, running a job at 100% power and 10% speed doesn't mean you can cut twice as deep, or twice as fast, as a job that ran 100% power and 20% speed.

[Rich Harman]

Running a job at 100% power and 100% speed is not the same as 50% power and 50% speed. By the same token, running a job at 100% power and 10% speed doesn't mean you can cut twice as deep, or twice as fast, as a job that ran 100% power and 20% speed.

I disagree. In my experience there is a correlation between speed and power that approximates a linear relationship. Not exactly of course, but similar. It does take roughly twice as long to cut through something at half speed and full power compared to two passes at full power and double speed.

However I am not asking about the speed/power relationship for CO₂ lasers, I already know that. I am asking if that relationship is different with fiber lasers. If so, why? Why can you not just slow down the gantry laser to cut the thin metal? Why do the number of passes need to remain the same, therefore making the gantry too slow?

[Dan Hintz]

Can these metal laser engravers like Epilog's fiber lasers cut stainless steel sheets (2 or 3 mils thick) or only mark on them? Thanks!

Do you truly mean 2-3mils (which is 0.002-0.003" thick), or 2-3 millimeters? That will affect the answers...

[Jim Good]

Sorry, been away from the computer today.

Dan, I truly mean 2-3 mils. I'm needing to cut .002" stainless steel foil and also .003" stainless foil but I've only got a 35 watt CO2 laser so I haven't even tried cutting with it. I'm guessing I need something like an Epilog fiber laser to cut this material and wanted someone to agree or disagree that it would cut it or maybe just mark it.

Jim

[Rich Harman]

This is what Epilog says about their fiber laser cutting metal;

The Fiber Laser can only cut through very thin gauge metals. We've had success at cutting up to 0.012" (.30 mm) thick metals.

[Jim Good]

This is what Epilog says about their fiber laser cutting metal;

The Fiber Laser can only cut through very thin gauge metals. We've had success at cutting up to 0.012" (.30 mm) thick metals.

Thanks Rich. I couldn't find that info on their website. Looks like they should cut through 2 or 3 mils.

This material will be part of an experiment that will be flown on the Space Station early next year.

Jim

[Kev Williams]

I believe part of the answer of why a gantry can't cut like a galvo is heat soak. As I understand it (<<disclaimer ) the beam moving via high-speed galvo is only within a, lets say .015" (for example) area for an extremely small period of time, which allows the laser to effectively cut or vaporize 'unobstucted' by the beam itself, whereas moving the beam via turtle-speed gantry results in the beam remaining in that .015" area for a laser-eternity, resulting in the metal simply getting too hot and melting down, rather than clean-cutting or vaporizing. More power would likely make it worse, meaning to get a gantry to effectively cut or vaporize metal without melting would require much LESS power. But that would mean several laser-eternities to get the same job done as a galvo in a minute or so; the beam can hit the same spot over and over very quickly, but with plenty enough dwell time to prevent melting.

Think of a cutting torch, there's an optimum speed depending on the flame (power), higher power, must go faster...

--as I understand it!

[Scott Shepherd]

Fibers put a LOT of heat (energy) into an area when trying to cut things like thin metal shim stock. Be prepared to have it warp and twist substantially, as well as discolor.