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View Full Version : New here and wanting to build a CNC laser cutter machine



Gravatel
07-02-2014, 07:39 PM
Hi there,

Very new to the whole CNC field and I am interested in building a CNC laser cutter machine. I would mostly be using it to cut 25mm-110mm thick foam (the grey type used for camera cases) on a regular basis with the option to cut thin wood and plastic if needed.

I know next to nothing but I am willing to learn and would be looking for a list of items I would need to buy and a guide on how to build it. I live in Buckinghamshire and would be willing to travel if not too far if needed.

Any help would be appreciated, thanks.

EddyCurrent
08-02-2014, 12:00 AM
I think you will have to put a specification together, size of machine bed etc. then read the Build Logs on this forum that interest you. Once you get a basic understanding, the format is to draft up an outline drawing using something like the free 'Sketchup' http://www.sketchup.com/ so that forum members have something to look at and discuss. Keep in mind that a laser cnc does not need to be as robust as say a router cnc but I suppose if you did build it strong you could fit a router later if you needed that.
These sites are okay for initial reading, they are American and we do some things a bit different but they are still good reads;
CNC Router Source: The Ultimate Information Resource (http://www.cncroutersource.com)
DIY CNC: Build Your Own CNC, CNC Router, or 3D Printer (http://www.cnccookbook.com/CCDIYCNC.htm)

cnc components already drawn in Sketchup format

http://sketchup.google.com/3dwarehouse/search?q=cnc&styp=m&scoring=t&btnG=Search

Gravatel
08-02-2014, 12:40 PM
Thanks for the response.

Upon looking at those links the machine would have a a mobile gantry with a 30inch x 20inch frame with the diode higher up so I can cut up to 110mm (I'm not sure if it would be better or not to have a z axis for it).

From my understanding I'd need servomotors for it to cut at a fast speed?

Something like this is what I'm ideally after M350 50W Laser Cutter - R22 cockpit faceplate - 3.5mm dense foam - YouTube (http://www.youtube.com/watch?v=k73eT3ehYB8).

Thanks

firetrappe
08-02-2014, 04:47 PM
I'm not sure a laser cutter would be the best option for your requirements. Personally i'd be looking at a router, possibly with an oscillating knife setup for cutting closed cell foam inserts. Have a look at this video I found, is this the type of thing you want to do? : AXYZ CNC Router Knife Cuting Foam - YouTube (http://www.youtube.com/watch?v=HZbz1WRSWAw)

I can't say i've ever seen a DIY machine with an oscillating knife, but you soon learn on here that most things have been done before.

Si.

Gravatel
09-02-2014, 12:19 AM
I don't think I'd need an oscillating knife as the foam isn't very dense.

It's the soft type like this 1600x900 150w co2 laser cutting out Polyurethane foam by HPC Laser LTD - YouTube (http://www.youtube.com/watch?v=ErernoyeoHM) just 110m thick.

Cheers!

njhussey
09-02-2014, 01:04 AM
I used to cut the foam (V28 is the grey stuff you're in about) for DFS sofas and we used big (52" of exposed blade) band knives with moving tables. We had a CNC machine for cutting out shapes and that again was a band knife (Fecken Kirfel was the make, or spelt something like that) but with 6 steppers to drive the blade and twist it. If you try to use a simple blade then as soon as it gets blunt (which it will quickly) it will tear the foam. You'll be better with a reciprocating blade or a band knife and moving/swivelling table.

GEOFFREY
09-02-2014, 01:09 AM
I don't think you have a hope of finding a laser that will cut 110mm deep at a reasonable price, and you certainly will not Knife-cut foam that deep without some form of vibration/oscilation. I think that hot wire cutting will do it though. That's my opinion anyway. I do not mean to be negative, but realistic. Good luck with whatever you decide. G.

cncJim
09-02-2014, 01:25 AM
I don't think I'd need an oscillating knife as the foam isn't very dense.

It's the soft type like this 1600x900 150w co2 laser cutting out Polyurethane foam by HPC Laser LTD - YouTube (http://www.youtube.com/watch?v=ErernoyeoHM) just 110m thick.

Cheers!




hi gravatel, did you see the end of the oscillating knife vid? I only ask as it shows the guys pulling the cut shapes out and the foam looks pretty flexible and not very dense?
Jim

GEOFFREY
09-02-2014, 02:36 AM
hi gravatel, did you see the end of the oscillating knife vid? I only ask as it shows the guys pulling the cut shapes out and the foam looks pretty flexible and not very dense?
Jim

It is also very thin - nothing like 110mm. G.

Gravatel
09-02-2014, 02:38 AM
Thanks for the replies guys.

cncJim, yeah I did watch the video but that seems quite hard foam like njhussey v28 foam.

I really need the laser to do things like this http://www.lasertouch.com.au/Foam/files/full_size_image_0_544.jpg as this is the primary purpose of the machine which I think a saw wouldn't be able to do?

GEOFFREY, if a laser isn't powerful enough I could do 2 55mm and glue them together but I thought there would be lasers strong enough?

Cheers!

GEOFFREY
09-02-2014, 10:59 AM
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
09-02-2014, 12:02 PM
How about something like this mounted to a cnc machine? Possible?

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

Jim

Gravatel
09-02-2014, 01:03 PM
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
09-02-2014, 02:17 PM
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
09-02-2014, 02:57 PM
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
09-02-2014, 03:43 PM
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
09-02-2014, 04:06 PM
Also you have to remember your eyes as a little shot of bounced laser light won't do them much good:hurt: ..Clive

Gravatel
09-02-2014, 04:18 PM
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
10-02-2014, 12:33 AM
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
10-02-2014, 01:14 AM
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!

Gravatel
13-02-2014, 11:06 AM
No one knows which type of laser/lens and power supply I would need?

gavztheouch
13-02-2014, 12:38 PM
Hi, the best thing would be to have a look at this website buildlog.net - CNC Laser Buildlogs (http://www.buildlog.net) plenty of info on laser building there.

Gravatel
13-02-2014, 05:10 PM
Thanks will check it out, just need assistance with the router now :/