YAG's and stainless

[Joe Hillmann]

After seeing the rings that Bruce Boone does I decided to see if I could also cut into metal like that with my laser. I took a piece of steel, polished it up and it cut in nice and neat with the bottom turning black. I am now trying it on a piece of stainless, I am on about the 100th pass and all it is doing is marking it and getting it pretty hot but not engraving.

Basically I am wondering is it possible to cut into stainless with a yag?

What about other metals?

Silver?
Brass?
Copper?
Pewter?
Aluminum?
Titanium?
Cast Iron?
Lead?
Tool steel?
Zinc?
Tin?
Nickle?

I know gold engraves deeply, but is to expensive to play with.

[Dan Hintz]

Joe,

YAG's provide more opportunities than CO2... play around with frequency, too, not just speed/power. You can get (somewhat muted) colors with the right settings, and stainless is a good substrate for this.

[Joe Hillmann]

Dan, I am finding out that focus has a lot to do with a yag as well as the other settings, I find lighter color objects engrave better if they are about 1/4 inch above the focus point. I need to do some testing to find the best focus for every type of material I usually run.

[matthew knott]

You can cut stainless (and engrave it) easily but you need the right equipment, and a think form previous chats you have a F254 lens, on a cobra that has a x4 fixed beam expander the spot your laser has is just going to be to big. What you can (and are doing) is annealing the stainless, you (as Dan points out)can actually get colours, silver, gold, red but its not really a repeatable process and has limited commerical valve. Titanium can give you really cool colours. Focus is focus no matter what material, but when you annealing being slightly out of focus can give interesting results as you finding. I have a program for scriba that consist of loads of small squares, each one is marked at different settings, basically a big grid of increasing powers and frequencys. You can run this on a peice of stainless and then pick the square that looks best and use those settings, if i can find the program for your laser i can email it over to you but it only takes about 10 mins to right your own.
If you want to cut and engrave metal then invest in a F100 or F163, it will cost you about $300 for a cheap one, you just unscrew the current lens and screw the replacement in, 30 seconds max and you will be blasting away. What you looking for is sparks, sparks are bits of material flying out.
Like this http://www.youtube.com/watch?v=TKpj5EiGaBY

[Joe Hillmann]

Matt,

Just to make sure I am understanding you correctly, I can cut metals with the laser that I have with a different lens? With one of those lenses what will be my marking area. And which one of the two that you mentioned would give me a more powerful spot?

[matthew knott]

To be honest its still not going to be an ideal choice for cutting metal, you need a big 2kw+ laser for that, but it can be done slowly, engraving metal (deep) can be done with multiple reapeats, the 100mm will give you the smallest and hence most powerfull spot but marking area is about 80 x 80mm (circle) 160mm not as good but gives a 120 x 120mm area. Yours 254 gives a big marking area about 210mm but not good for deep engraving and metal. The 160 lens was standard for most machines unless something special was needed.

[Joe Hillmann]

I know I won't be able to cut metal but after looking a Bruce's website I wanted to see if I can match the deep engraving that he does on his rings. The only thing that I could cut deep into was a piece of cold rolled steel. Everything other metal I tried today I could maybe get ten thousandth's into and after that no amount of passes made it go any deeper.

Would the lens from the Hans fit the electrox? I will have to see what size it is tomorrow.

[Dan Hintz]

To be honest its still not going to be an ideal choice for cutting metal, you need a big 2kw+ laser for that

You only need the 2kW range if you're working with CO2 wavelengths... only a few percent of the power is absorbed by metal at those wavelengths. At YAG wavelengths, the vast majority of the power is absorbed, so a lot less power is necessary. You can cut very thin sheets without a problem, like stuff you can bend between thumb and forefingers... thicker stuff (like tin snip thick) you'll need to go much slower and/or use several passes. 35-40W is nothing to shake a stick at...

[matthew knott]

Thats true Dan, when i say thicker i mean 5mm + at quick speeds, even cutting thin say 1mm sheet will take a long time with a galvo 40 watt yag. A proper cutting yag setup will have a short focal length lens (20mm or less) and more important a cuttting nozzel with gaz assist, the gas makes a masive difference, turn it off on a cutting system and see what happens, even a 2kw struggles on thin sheet.
Good example here, you can see the speeds and this is a 3kw fiber (same wavelength as yag) and a cutting nozzel and gas.
So 100 times the power, a lens 10 x shorter and gas, and its not exactly flying (i know this machine and it was running flat out for the video any quicker and it didnt cut all the way). The cobra laser is really not good for cutting but if you have plenty of time it will eventually get through. I will try cutting a 20mm cicrle (out of 1mm 316) tomorrow at full power on a 50 watt fiber and time it, i think it will take about 2-3 minutes

[matthew knott]

To be fair the last vid is cutting brass and alu (much harder than steel to cut) heres a laser with slightly more power on 2mm stainless, you can hear the gas doing the work.http://www.youtube.com/watch?v=tThroVYhMyw

[matthew knott]

Not sure on the hans laser lens! Ours doesn't but it's a smaller scan head, check the focal distace! If it's the same on booth there's no point in changing it! If its an 82 x 1mm thread then it should fit ! Is the hans no good at deep engraving?

[Bruce Boone]

I use a F100 lens to get the smallest spot possible. I believe it's around 16 or 18 micrometers. It does take me about 16 passes at a low frequency, like 20khz to get the deep engrave. It kicks up serious sparks and some of them get on the lens protector. Some rings take almost an hour even at full power. On cutting, it will indeed take hundreds of passes. The trick is to have the path wide enough so the beam is not blocked when it goes deeper. I did a chainring ring where it was all cut out except for the thin standing chainrings, and it took a full 2 hours on the laser. I'm looking into a 400 watt cutting fiber laser to help on those.

I was just doing color trials on titanium today as a matter of fact. I am also checking into blackening zirconium with the laser. Sometimes we make black zirconium rings, and they have an oxide layer like a bathtub on them that gives the color. If that gets scratched through, it's tough to fix on some types of rings. I'm looking to see if the laser might help me out on those.

One of the easiest things to cut is business card thin aluminum. Try a small design like a square or circle to find out how many passes it takes to get through. It might be 200 to 300 or so.

[Bruce Boone]

Here's the system I'm checking into: http://www.youtube.com/watch?v=jSO-2bqfPBI&feature=related This is a Trumpf Trucell system, which uses a choice of lasers including a 400 watt fiber. It looks superbly engineered and manufactured. I have been looking for years for a system that would do both deep engraving and cutting. I've come to realize that they seem to be really different animals, so I am now looking to do both tasks with 2 separate lasers. I love my YAG and will keep it, but it only whets my appetite for the higher end stuff it can't do.

If anyone here knows another system that can do both rotary and plate with a minimum of 400 watts in fiber, please let me know. I want to make an informed decision. This would cost an arm and a leg, there's no doubt, but it should enable me to do some pretty crazy stuff, like my chainring ring, the Mechanica ring below, and similar type designs. I had LaserStar check into it, and they could not do it. I have Rofin on the case now, but again, this is something not normally done. They have 40 watt systems used as engravers, so the cutting technology might not be their forte. The only system I've seen that comes pretty close to what I have in mind is the Trumpf. Basically a huge industrial laser without all the huge stuff.

[matthew knott]

Hope you have deep pockets for the Trucel is megabucks, be aware most cutting machines are normally CW (continues wave) and engravers are pulsed, the cutting machine (agian most) wont do a good job engraving. There are micro machining systems, the type used for stent cutting that might do what you need, pulsed fibre laser are getting more powerfull by the day, SPI and IPG seem to rule the world of fibre lasers but you might find a cheaper 50 watt pulsed fibre will cut quicker (than your current setup) and still engrave and not cost the earth. What laser setup are you currently using..Rofin but whats the power

[Bruce Boone]

Rofin is my welding laser. Sysma is my YAG. It's 80 watts. That was the most powerful engraver that I could find. I did try a 50 watt fiber when I first checked into the engraving system. It didn't have the same oomph as the YAG. The stent systems are plenty good for super thin stuff, but I'd like to cut through 3mm titanium. I have some samples out at SPI now. Do you have a feel for a cost of a system like that? I still don't have any quotes, but I know it will be tough. I would expect $100-200K, but that's just a guess.

I agree, it seems that SPI and IPG are the only games in town for high power fiber. Trumpf bought SPI a while back, so that's why I'm leaning that way. There are 400 watt fiber systems from China, but all you have on the Internet is a very sparse spec sheet and nothing to make you feel very comfortable. If they were imported into this country and repped by a company here, I might feel more at ease with that. I do want the extra power just for room for growth. I'd like it to be "an answer looking for a question." I would be able to do my old bike parts and other flat stock things as well as rings and other stuff that I haven't yet thought of. I would assume that even though it is continuous, and might even take G code, I could do some manual hatch patterns at a lower power to do some engraving. Let me know your thoughts on that.

The system is somewhat of a hybrid, so I don't think too many companies will be making something like this setup. There might be boutique builders out there that would put together a custom system from components, but I'm not aware of them now.