New here and wanting to build a CNC laser cutter machine

[GEOFFREY]

It wasn't so much the laser power I was thinking of (that foam shouldn't take too much cutting), but the depth required under the laser head. I don't know much about lasers - I bought a new Blackcat laser 900x600x60watt a couple of years ago and have never
managed to get it set up!!! On that machine the focal length above the material is about 6mm (can't remember without checking) and probably only about another 20mm to the bed. If you do build the machine of your dreams I think that you will need to have a rise/fall table or use a packer system to cut thin material. When I have looked at cut-outs in that sort of material I have never had the impression that it was laser cut although the engraved logo on you link does look to be. G.

[cncJim]

How about something like this mounted to a cnc machine? Possible?

http://www.craftershotknife.com/Home_Page.html

Jim

[Gravatel]

The thing is I know two companies who use a laser machine for this stuff so I would assume I could do this also. I just don't know all the specific parts I need :/

Cheers!

[Neale]

My guess is that the biggest problem that you will face is the laser itself. There are some laser diodes coming on to the market which are relatively easy to use but still limited to around 2W or so (unless you pay big money for something that is electrically pretty fragile) but they won't do much more than cut paper or scorch wood. Maybe, just, cut thin balsa according to some accounts. After that, you're on to gas lasers with the power supplies, optics, and general mechanical fragility. And they aren't cheap either - you will be paying more for a gas laser tube and its power supplies than a 2KW router spindle unless you strike lucky on an auction site.

Mind you, the AXYZ oscillating knife assembly is just under £6000...

[Gravatel]

See I was going go get the LS3020 pro for £1,125 but it doesn't have much depth to cut 110mm and I would need a better lens so in my mind I should be able to make a bigger version for cheaper surely?

[Neale]

I guess that that is a second-hand price? HPC appear to list them for about twice that price, plus VAT...

Mechanically, I'm sure that you could build the moving bits for a lot less. Last laser cutter I looked at was about A3 cutting area, belt drive rather than leadscrews, and all the moving bits pretty light weight with zero cutting forces to cope with, unlike a router. Simpler/cheaper slides and guides, etc. It's the laser tube, mounting and housing, optical path, power supplies, etc, that will provide the complications. Really interesting project, though, although given that you don't see build logs for them that often, a bit more challenging than a router or even mill conversion.

[Clive S]

Also you have to remember your eyes as a little shot of bounced laser light won't do them much good ..Clive

[Gravatel]

The price for the LS3020 pro doesn't include VAT but that's the cheapest they do.

Yeah exactly, I don't know which parts to get, that's where I was hoping I could get help on that?

Yes I will buy some goggles :p

Cheers!

[gavztheouch]

I have retro fitted a few cnc routers but the only machine I have built from scratch so far is a co2 laser.

With your 110mm foam you will need a lens with a long focal length. The beam straight out of a laser is for example 1mm, you need to focus this beam into a small diameter with a lens to give you all that cutting power. Just like a camera lens the beam will converge at a set distance then the beam will start to spread out again. To cut your 110mm foam you need to keep the beam focused for as much of the thickeness of the foam as possible. To help with this you should focus the convergance point in the middle of the foams height.

A chinese 40w laser will cost about £90 for the glass tube plus £130 for the power supply

The cheapest option for your linear rails could be makerslide. It was an american opensource project but I think I guy in the UK started producing it here too.

[Gravatel]

Thanks for the reply I have £1k but would like to try and save some of it. Would you be able to list which laser, lens, power supply I would need?

Cheers!