Hello,
Is it possible to engrave and cut on a 1 mm mild steel plate with a 60w CO2 laser?
I have searched this forum but I can’t find anything specific and I don’t want to damage the laser or worse by trying “blind”.
Any advice is welcome.
Greetings and Merry Christmas 
In short, no.
Metals reflect most of the light from a CO2 laser, and act as very good heat conductors. With a 130 to 150 w CO2 and oxygen assist it is possible to cut thin metal, but it is slow, relatively dangerous (oxygen!), and usually uses a special metal cutting head.
In addition to reply from Oz, to ‘engrave’ metal there is a product called Cermark that achieves this.
It’s expensive.
Cutting with 60W isn’t possible. But you can ‘mark’, using various methods including etching off painted coatings, bonding a coating, such as Cermark or molybdenum disulphide (moly spray), bonding paint, bleaching anodised coatings, etc.
Even at higher wattages, laser cutting and ablation require specialised machines, capable of handling the extreme heat of molten metal as well as the fumes produced.
A high-wattage machine not designed for metal can easily crack lenses, coat mirrors and lenses and other parts with metal vapour.
There are cheaper options, one being fibre lasers with galvanometric heads. They can’t cut, but can natively engrave metal. And compound lenses can get the light pressure high enough to ablate metal, but at some cost in lenses and lens tube and there’s still the problem with excessive heat - reasonably easily overcome.
Thanks @Bonjour @OneArmedGraphics @LightBurn
The conclusion I draw is that steel is better not to touch it with a “Chinese” CO2 60w 
I understand that with anodized aluminum you should have no problems.
At the moment with MDF, Methacrylate and plywood the cuts and engravings come out well.
Beginner’s luck! 
I will keep boring you around here with my tests.
Now that I have bought the LightBurn License I am not leaving here… 
Just to be clear, with anodized aluminum, you can engrave it without additional “mark agents”. You still cannot cut aluminum with a CO2 generic laser.
I understand that I can “engrave” letters, drawings, etc., but not make the cut, right?
Thank you for your good advice.
Don’t discount painted metal - even steel, if you have a good source of material.
I engrave painted, anodised aluminium. It’s anodised ‘gold’, with a black enamel coating. when you remove the top coat, you are left with the anodised colour beneath.
Careful settings and proper paint curing times can achieve the same effect, by ablating the top coat, but it’s a lot easier to just spray over anodised sheet.
ACP (aluminium composite panel) is great for solid objects. It comes anodised in a wide range of colours, can be machined with normal woodworking tools, and is stable outdoors for ~20 years. I buy mine from sign supply stores, or just go to a local sign shop for a small quantity or for offcuts (sold cheaply - they throw away a lot of smaller pieces, perfect for laser engraving).
Hi,
I bought 2 small (supposedly) 4mm anodized aluminum plates, but I don’t have the security to put it in the machine to engrave a drawing and have the laser damaged.!
Thank you for all the help you give in this forum, it is spectacular.
It wont damage your machine
@Bonjour is correct. It won’t damage your machine.
I know it sounds crazy but I saw a FB post yesterday where someone with a 50W CO2 (10mm/s 60power 0.01mm fill) actually engraved (with some depth) on stainless steel by using a layer of ketchup on the metal to be engraved. It has something to do with the acidity. It was crazy, they tried mustard, ketchup, and some other condiments but ketchup worked the best. https://www.facebook.com/groups/LaserEngravingAndCuttingGlobal/permalink/2695238424119659
