CNC questions (for foam cutting) - RC Groups
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Aug 31, 2005, 09:06 PM
Registered User

CNC questions (for foam cutting)

I've read a few threads pertaining to CNC on these forums, but I'm not exactly sure what I want/need.

I'd like to build a machine to acurately cut the typical foamie plans in FFF. I get tired of cutting by hand and a (relatively inexpensive) cnc machine interests me for other uses as well.

It seems that a CNC router or a CNC foam cutter is what I am looking for. I think the router is more of what I want. THe foam cutters appear to be more suited to cutting out wings.

Can you use a router on foam? Can you cut profile parts with a CNC foam cutter?

Does anyone out there use a homemade cnc router or foamcutter for cutting FFF and how do you like it? What plans did you use?

From what I have read, the plans on are respectable.

What do you think?

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Aug 31, 2005, 10:19 PM
Registered User
For cutting FFF, I'd think that a vertical hot wire on an X-Y axis would work very well. By not having to cut in the Z axis, you simplify the machine incredibly.

I bought plans off Ebay, which are not as detailed as I'd like, but they describe making a 3D machine out of 3/8 all-thread and some surplus stepper motors "for less than $300". You could very easily do something like that which would be plenty accurate for cutting FFF flat pieces as you don't require .001mm accuracy or anything like that. You could probably do it for $200 or so I'd guess and it'd be a fun project IMO... Maybe once I actually get a stupid motor to work (tried 2 GBv and they suck! grrr) I'll get to build my first FFF and get "hooked" and I'll build such a machine

EDIT: That's a super-cool site you gave the link for -- I bookmarked that for ideas on other machines I've wanted to make!

Aug 31, 2005, 10:47 PM
Registered User
attached picture of my cnc router that I use to cut out foamies. If you have any questions let me know.
Aug 31, 2005, 11:02 PM
Registered User

did you build it yourself?
what are your dimensions?

yours looks expensive!
Aug 31, 2005, 11:06 PM
Registered User
looked at some of your previous posts, planeflier

good info for me there...thanks
Sep 01, 2005, 12:24 AM
Registered User
Planeflier: what software did you end-up using? How does that work with the PDF plans (wondering if there's a line tracer routine for pdf or if you re-capture the drawings).

Sep 01, 2005, 07:52 AM
Registered User

I use mach 2 and sheetcam. as far a pdf's I found a shareware program that will convert files from pdf back to dxf file format. I have also used Adobe Illistrator to convert from pdf to dxf or dwg.

Let me know if you have any more questions.

Sep 01, 2005, 10:01 AM
CeNeCe PRO rules!
DaniSaez's Avatar

I use a home-made hot wire foam cutting machine, and my own software I've develloped.

To cut foam wings, fuselages, letters, any shape you want, shockflyiers, depron, you name it; you can 3D preview, and eve build virtual 3D kits!

You can check the soft at

in the pics you can see my cutting machine layout (002), at work (004), and the results (005) of cutting an hydro-foam.

Sep 01, 2005, 10:03 AM
CeNeCe PRO rules!
DaniSaez's Avatar
BTW, the soft is called CeNeCe PRO!

Sep 01, 2005, 02:07 PM
Soil Density Tester
TexasAce's Avatar
The problem with a vertical hotwire is gravity. How do you support the foam and connect to the wire underneath the foam? Routers don't have this problem.
I told my wife I wanted a laser cutter for Christmas. She suggested a letter to Santa. I'm not sure how to take that.
Last edited by TexasAce; Sep 01, 2005 at 02:07 PM. Reason: kant spail
Sep 01, 2005, 09:15 PM
Here is where you need to go if you want to know everything about cnc and check out my cnc laser-
Sep 02, 2005, 05:23 AM
CeNeCe PRO rules!
DaniSaez's Avatar
Hi TexasAce, just place the foam on the table. btw, I don't see why you want to connect the wire "underneath" the foam??

In my case I'm not using a bow to hold the wire, it is fixed on one side, and has a small weight on the other to keep the wire tight. If I want to place my wire under the foam, I just have to connect the wire after placing the foam. I use this system only with depron, to keep it hold and tight, for normal thicker foam you don't need those supports.

I wouldn't say gravity is a problem for vertical hotwire cutters, on the contrary, for the vertical axis, gravity eliminates any gap or backslash you might have, as tension is allways kept in the same direction.

Furthermore, for flat shapes, I agree with you tha a router might be more adequate, but when it comes to 3D shapes... You cannot cut a hollow fuselage 10x15x50cm with a router, can you?

Sep 02, 2005, 01:53 PM
JohnVHRC Reviewer
JohnVH's Avatar
Hi, the best cleanest method is a laser, which is how all my kits are cut, the plywood and plastic are also cnc laser cut in our shop. BUt, these can get spendy.
Sep 02, 2005, 08:26 PM
Registered User

Interesting that you would say gravity is a help! I was reasoning that gravity would be a big problem, so initially I was leaning toward the router.

So for cutting the typical foamie plans you would reccomend the foam cutter over a router?

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