CNC Millable?

[JAS]

Hi All,

I was wondering if you CNC mill guys might know how hard this is to do to a foamy? I was considering doing this to 1 or 2 of mine if it isn't too much hassle. I think I've seen this done in Europe about a year ago.

Thanks

[Mithrandir]

Simple... 3 axis router.... a bit of sciencing out to hold the foam without lifting (Vacuum Table? And/Or simple fixture)) and the right cutter and speed to make clean cuts with no break out... but once that is figured out... it is simple to do... in the 3rd image... you can even see the tool marks from the cutter ... I would suggest a ball cutter so the bottom of the pockets are radius'd rather then a sharp corner... (Stress riser's yuh'know?)
If you can find foam thin enuff...the trusses can be sculpted and then bonded to the full profile fuse... not as good as machined.. but "Home Shop'able"

[chitty3d]

Believe me, I am sure it is not that easy.

[jst4fun156]

Probably take about a day to write the programs, a few hours to trouble shoot and you could be in buisiness in a couple of days, somebody with mastercam experience can whip that off in no time, provided it could all be done on a flat surface it can be held down with 2 sided tape - no fixturing involved. Pick up the part and press the start button!!!! Not hard if you have the experience and equiptment. Once a program is written you can mass produce

[Redneck Shaun]

The hardest part would be how to hold it down with out crushing the foam. After that is done the cut out on a CNC mill would be as simple as programming it.
A vacuum table might very well work as seeing there is not going to be much resistance on the cutting bit.Cool idea.......Very doable!!

[Diablo2006]

I once cut out a foamy on a Viynl cutting machine with a new blade in it for a design project at college and it cut it out really well, straight from a .PDF

[Pro1Foam]

	Quote: Originally Posted by Diablo2006
	I once cut out a foamy on a Viynl cutting machine with a new blade in it for a design project at college and it cut it out really well, straight from a .PDF

Interesting...

[Mithrandir]

	Quote: Originally Posted by chitty3d
	Believe me, I am sure it is not that easy.

Ummm... yeah... We do stuff like this all the time... in aluminum, carbon precure, ti... Cress....

Can't use tape to secure it as attempting to remove the foam sheet will damage/destroy it...
Likely best to cut all the internal pockets first on a big blank sheet.. then cut outside perimeter of fuse, tails, wings etc...

I could 3D model it in about 2 hours (In Pro-E) if I had a physical representation or paper drawing... less if a dxf or iges or x_t file existed.

CNC tool paths... likely a couple hours....
Biggest challenge is holding down such a fragile item... if the sheet bows, it bows INTO the cutter... so a vacuum table is likely best solution... but... when cutting 2nd side... the pockets from first cut/side will tend to collapse due to vacuum... so a fixture that is a male reflection of the part would be needed as a support... this could be cut from anything... from foam up to aluminum....
this is not hard... but... usually everyone involved in this process professionally gets paid from $25.00 to $60.00 per hour... so it can be costly unless you find people with the resources who are also model airplane afficianados...

I can do the CAD work....

[Mithrandir]

	Quote: Originally Posted by Diablo2006
	I once cut out a foamy on a Viynl cutting machine with a new blade in it for a design project at college and it cut it out really well, straight from a .PDF

That is a great idea for the perimeter... but the pocketing is another challenge that I think was the primary interest in the question asked by Jason...

[Mithrandir]

DUDE!!!!... this is a snap!!!!...
Make a template and use a simple hand router with carefull attention to the depth!!!!

I bet it would work great!!! I am gonna try that one myself!!!!

[JZiering]

	Quote: Originally Posted by Mithrandir
	when cutting 2nd side... the pockets from first cut/side will tend to collapse due to vacuum...

The plane is only milled on one side of the foam... Much easier this way.

[paffy]

So what about equipping the CNC mill caddy with a "push plate" that would keep the depron from bowing up ?

P.

[paffy]

Or maybe sandwiching a full profile with a truss part ? That way, you don't need to go back and forth through each opening, just the perimeters.

P.

[Fancyfoam]

I would encorage everyone to try this. The Vrolet in the photos is a one of a kind plane that I cut for Jason Noll. This was after Jason saw a lightned xcalibur F3P plane I cut for Brandon Chitty. Caution: Don't crash one of these planes. They are super fragile. Also, the basic design of the plane must be perfected first. The lightness makes it fly slower, but won't solve basic aerodynamic issues (don't lighten a Flatout!).

Remember, you need leave only .02" of foam in all of the pockets to take out as much weight as possible. Once you try it, you'll have a better understanding of what you are looking at. Not rocket science, but not as easy as it looks.

Give it a try! You'll see what I mean.

Mike Hammel
www.fancyfoam.com

[EddieWeeks]

If I were to do it.

The biggest problem would be getting the design from Jason's Head to
a cad drawing...

A custom vacume table could hold that stuff no problem as the tool
pressure is next to nothing...

I often cut 5/8 Aluminum plate by simply glueing it to some other Aluminum.

Eddie Weeks