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Moving from a laser to CNC

Posted: Wed Oct 09, 2013 12:43 am
by Bandelore
OK everyone I am so new at CNC...I am a music teacher who recently discovered my local Community College has a Fab Lab, which is free for community members and students to use. I have been messing around with the Epilog Lasers in there to make things out of acrylic like the crown on this piece of art
and this yo-yo display case with custom cutouts to hold and display yo-yos:

I have been struggling to make these cases because the time on the laser is hard to come by. Buying my own laser would cost well over $20000, and I have nowhere near that kind of dough, but I figure I could cut out those shapes with a CNC machine no problem. I found the shapeoko and although it is too small for me to use, I LOVE the idea of it.

If I were to order the kit from instructables (I realize the shapeoko 2 is available soon, let's assume I would get one of those), how difficult would it be to set it up as a larger machine?

I have a limited budget, but my needs are pretty simple. All I want to do is cut out some mushroom shaped openings in scrap acrylic and drill some mounting holes. I don't need a 4 axis machine or something amazingly precise. Most of what I do is art. I honestly believe the machine can pay for itself if I can get it up and running...I just don't know how big of an "if" that is.

Is there a resource which would be appropriate for someone who is still not sure what all the terms even mean? I am used to sending a Corel file to the laser and making it cut out what I want. I feel like I am using a light saber to cut bread. A Shapeoko would be great for me.

Here's what I have looked at so far - Guerrilla guide to CNC machining -
Fab Cenral -
and I am specifically interested in the Panel Eater - and other ways to scale the thing up.

What's killing me is seeing all these 3-D cad drawings of monster homemade CNC machines. I am nowhere near ready to enter that world yet; I can't design a machine until I get one and start messing around with one.

One final question - if I have a piece of acrylic which is long and skinny, would it be able to fit under the shapeoko and have shapes cut out of a specific part of it? Or possibly could I make each side a mirror image of the other side by turning the piece around and programming it to cut the design in a mirror image? Most of my displays are just under 2 feet long on one side. (I use the scrap ends of acrylic I purchase at $1 per pound from the local plastics fabrication shop in Cleveland - My sizes are kind of "take what i can get.")

Sorry for the lengthy first post, but I appreciate any and all help you can provide.

Re: Moving from a laser to CNC

Posted: Wed Oct 09, 2013 2:34 am
by WillAdams
I think it's pretty easy to assemble one and then upgrade it --- tried to get everything in the wiki.

I think the biggest ``bang for the buck'' is the basic machine, extended to 1M Y-axis w/ one left-over piece of MakerSlide used to double up the X-axis --- that's what I did (and then upgraded Z to an Acme screw).

Re: Moving from a laser to CNC

Posted: Wed Oct 09, 2013 2:35 am
by Enraged
Not to pull you from building a CNC, but buildlog has a great design for a low cost DIY laser cutter:

Re: Moving from a laser to CNC

Posted: Wed Oct 09, 2013 5:28 am
by Improbable Construct
The basic machine is pretty simple to understand once you have it in front of you.
It is easily expandable and infinitely upgradeable.
The biggest hurdle you will face going from a commercial laser to a open source CNC machine is the electronics and software stack.
With the epilogue you draw in Corel and more or less hit the print button.
A CNC machine needs a couple more steps.
First you draw your part using some sort of CAD software.
Then you have to create a tool path using CAM software.
Lastly you need a piece of software to send the G-code created by the CAM software to the machine.
It sounds like a lot, but it just take a bit of patience and some learning time.
The electronics are also a bit confusing.
You can go open source with tiny G or the Grbl shield of you can go the TB6560 controller route from eBay.
The tiny G and grbl shield use a USB connection.
The TB6560 based controllers require a parallel port and mach3 or linuxCNC to run.

I have a shapeoko running with a tiny G, a heavily modified shapeoko running with a gecko G540 driver and Mach3 and a buildlog 2.x laser.
If you can find the aluminum parts, the buildlog laser can be built for $2500 or so.

Sorry for the ramble.
The whole point if the story is yes the shapeoko should be able to be easily and inexpensively expanded to do what you need.
The one minor thing I should mention is that it will not leave the nice polished edges that a laser does.
Feel free to ask any more questions you have.
I am going to guess that I created more questions than I answered. :)

Re: Moving from a laser to CNC

Posted: Mon Oct 14, 2013 10:35 pm
by calica
Enraged wrote:Not to pull you from building a CNC, but buildlog has a great design for a low cost DIY laser cutter:
Other affordable laser options are:

blackTooth Laser Cutter kit $1700: ... raver.aspx
Full Spectrum Laser turnkey $2-4k:

Re: Moving from a laser to CNC

Posted: Mon Oct 14, 2013 11:41 pm
by cvoinescu
calica wrote:blackTooth Laser Cutter kit $1700: ... raver.aspx
Full Spectrum Laser turnkey $2-4k:
I think the 2.x laser is superior to the blackTooth (simpler to assemble, fewer parts, more robust; and I trust aluminum extrusion and Dibond to be stable over the long term, unlike MDF).

I hear the Full Spectrum units are very good.

Both are misnomers, though. blackTooth has no teeth, let alone a black one; and the Full Spectrum laser works in a very narrow band around 10.6 um: a far cry from a full spectrum. :)