Cutting laser?

[LPF Dude]

Hi all,

Newbie here. I'm researching what I need to make a laser cutter for acrylic. I already have a computer-controller XYZ machine, and want to add a laser diode to the head. Confused though due to conflicting info, so have some Q's...

Laser:
Will a 1W 808nm Laser diode cut 1/16" acrylic? What about 1/8" (which I may need to do occasionally). I don't want this to struggle, so if 1.5W or 2W is necessary, I will get that. So far, the big companies are saying that I need a gas laser for this, but in several other places I'm seeing that a diode laser would work. I really like the idea of an all enclosed flashlight-looking laser with the key switch, but can put the system together once I figure out the correct diode for the application

Power source:
Guess I can figure this out once the diode is selected.

Safety material:
Rather than just safety glasses (which I will get), I would feel much safer enclosing the machine, but would like to have at least 2 sides transparent/translucent. What material would I need for this? I'm assuming the same stuff that the glasses are made of, but is this easily available in sheets?

Thanks,
-Neil.

 

[ARG]

Safety material:
Rather than just safety glasses (which I will get), I would feel much safer enclosing the machine, but would like to have at least 2 sides transparent/translucent. What material would I need for this? I'm assuming the same stuff that the glasses are made of, but is this easily available in sheets?

Yes, I have seen the same material goggles is made out of in sheets in another thread, i'll try to find the website that sells them.

 

[benmwv]

I'm sorry, but 808 is not high enough in the infared spectrum to cut acrylic. Compared to a CO2 laser 808 is practically red... It will just pass right through the acrylic sheet.

You need to get a CO2 laser and use special lenses and mirrors to route the beam to your cnc cutting head

 

[LPF Dude]

What about a higher wavelength then?

 

[piferal]

As benmwv stated, to cut acrylic usually it uses a CO2 laser, not a 808nm diode,

and the most common wavelength for CO2 laser is 10600nm, or 10.6μm.

 

[Helios]

Nothing I know of in diode form will cut clear acrylic. CO2 is the only way to go but thats not a bad thing! CO2s can be had for pretty reasonable prices AND you dont need glasses. Just encase the entire thing in nice think acrylic. You wont get much for reflections since the wavelength is absorbed by most materials including acrylic. Just make sure you READ into the safety aspects before you take the leap.

 

[LPF Dude]

As benmwv stated, to cut acrylic usually it uses a CO2 laser, not a 808nm diode,

and the most common wavelength for CO2 laser is 10600nm, or 10.6μm.

What I meant by higher wavelength is if perhaps ~1k nm or more (but in diode form) would work. FWIW, the acrylic is colored -- red, blue, green and bronze. Occasionally I might do black acrylic, but I don't do clear. Thanks.

 

[LPF Dude]

Nothing I know of in diode form will cut clear acrylic. CO2 is the only way to go but thats not a bad thing! CO2s can be had for pretty reasonable prices AND you dont need glasses. Just encase the entire thing in nice think acrylic. You wont get much for reflections since the wavelength is absorbed by most materials including acrylic. Just make sure you READ into the safety aspects before you take the leap.

I should've been more descriptive at the start, that this is generally red, blue, green and bronze acrylic. All relatively dark. And occassionally black. Would that make a difference to the diode selection?

Also, what is reasonable for CO2? Only quote I got was $3800 for a self-contained 30W emitter (with electronics), but no power supply and I'd need a separate "galvo head". Do you know of a more cost-effective option?

 

[Helios]

I should've been more descriptive at the start, that this is generally red, blue, green and bronze acrylic. All relatively dark. And occassionally black. Would that make a difference to the diode selection?

Also, what is reasonable for CO2? Only quote I got was $3800 for a self-contained 30W emitter (with electronics), but no power supply and I'd need a separate "galvo head". Do you know of a more cost-effective option?

Thats way high although im sure at that price quality will be quite better.

These ebay tubes have been purchased before and the consensus is good

40W CO2 Laser Tube + Power Supply Cutting Engraving | eBay

That $388 for tube and PSU. You will need some optics and to set up the water cooling but if your froogle and creative that wont break the bank either.

 

[LPF Dude]

Wow, that's FAR better than $3800. Will need to read up on CO2 lasers.

Much thanks.

 

[Helios]

No problem just promise to post pictures when your done if you go the route!

 

[LPF Dude]

Will do. For now, here's the XYZ system we built. "We" = me and some high-school students I mentor independently...

.


Will take some thinking to add a CO2 laser, so will be at least a couple months before anything is implemented, and we're finishing a 3D printer project. To be honest, I'd prefer not to have any lasers around until they're off to college in a couple months anyway.

 

[Helios]

The only problem I see is that its pretty small. That CO2 tube will but quite a bit of weight with water circulating. You can use special mirrors to bounce the beam to the cutting point but thats quite difficult. With CO2 your best off with a stationary head and an XY table

 

[LPF Dude]

From memory, it's about 2ft x 1.5ft x 2ft high. X-Y travel is approx 18" x 12". Yes small, which is why the diode-type laser would've been so much nicer. But my thought right now is to mount the CO2 laser outside the frame, then use two mirrors. I need to figure out how to focus this with the varying distance from CO2 tube to acrylic. Also need to figure out backing materials for the bed, that would not absorb the CO2 wavelength.

Alternate plan is to mount the CO2 tube on the head of my CNC mill. That gives me about 14" x 7" of cutting space.

 

[Helios]

Mounting the tube on the head would save you some headache if the head can hold the weight. The problem is creating a focal point with CO2 is already a task in its self let alone a thin beam that stays thin even at differing focal distances. This is how some laser engravers/cutters are set up though so its not impossible.

LPF member "Things" was building something like this if I remember correctly.

 

[Tech_Junkie]

You can also use a fiber optic coupler. I dont know much about it, but I know a lot of people use it.

There are a few people here that can help you. You might want to make a thread in the "Gas" section of this forum. Another place to ask is Photolexicon. Just dont talk about pointers. Diode Virgin, and a few others there have working CO2 cutters.