CNC Foam cutting tool.

[Madmike8]

I've been planning on build a foamie for awhile now. The wife says I have to finish our house first.

So, I've been playing with my 3D printer to keep me occupied, and I ran across this.

http://www.thingiverse.com/thing:724999

image.jpg (99.53 KiB) Viewed 611 times

It's constructed with conduit and printed parts. Foam is pretty easy to cut, so I was thinking to extend the conduit out to be able to cut a 4x8 sheet at once. I'm pretty sure the Z axis will sag towards the middle, but a thick foam spoil board should make it acceptable.

What do you all think?

[mikeschn]

I think it's do-able. As long as you don't want to cut rabbet joints. I did that last weekend, and even though the rabbet joints weren't too bad, I cut them too close, not leaving enough room for the gg to escape. Result, bowed spar...

Here's a sample rabbet cut...



Mike...

[capnTelescope]

Looks cost effective. There's not much in the average build where the Z dimension is critical. Scale up your conduit size to make up for the longer gantry span.

[Madmike8]

I'm thinking about filling the conduit with expanding foam for extra support. I'm printing out parts right now.

[dales133]

You could use light gage tube on the longer spans or run tube inside the conduit

[typoagain]

I really like the design for a CNC machine. It looks like a fairly simple, lightweight design.
But I think the reason it gets away with using conduit for your main structural supports is because it is not carring the large motor that drives the cutting head. Apparently the cutting head is suspended above the machine and uses a flexible shaft. If you extend either the X or Y axes how to 9 foot so that you can cut an 8 foot sheet of plywood you're going to need to come up with a very long shaft and a way of suspending it to support the extra weight. Your other choice would be to move the drive motor for the cutting shaft and mount it to the main body of the cutting head. Then I worry that your conduit could not support the weight.