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Old Feb 04, 2011, 04:49 AM
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GMFC Foam cutting software

I am starting this thread to provide another forum to exchange about GMFC.

Gilles

http://www.gmfcsoft.com/
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Old Feb 04, 2011, 07:53 AM
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Thanks, Gilles, I think that this forum is a much better tool than Yahoo.

Love my GMFC!

Ward
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Old Feb 04, 2011, 08:07 AM
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Originally Posted by Ward Hagaman View Post
Thanks, Gilles, I think that this forum is a much better tool than Yahoo.

Love my GMFC!

Ward
My pleasure

Gilles
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Old Feb 04, 2011, 09:36 AM
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Billings MT
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Glad to see this happen!

Hi Gillies
Glad to see this Group come to life.
Bob in Billings MT
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Old Feb 05, 2011, 12:46 PM
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I wanted to post the first attachment!! Hope it brings back the warm fuzzies of your trip out here two years ago,

Doug Blackburn

P.S. Glad you had the time for us.
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Old Feb 05, 2011, 02:29 PM
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I wanted to post the first attachment!! Hope it brings back the warm fuzzies of your trip out here two years ago,

Doug Blackburn

P.S. Glad you had the time for us.
I am glad to see that you still have these pictures... This was definitely a fun trip

Note that with the GGC interface and the EXPERT version, you can have limit switches...

Hope to see you soon,

Gilles
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Old Feb 05, 2011, 07:48 PM
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United States, CO, Littleton
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Originally Posted by Twinboom View Post
I wanted to post the first attachment!! Hope it brings back the warm fuzzies of your trip out here two years ago,

Doug Blackburn

P.S. Glad you had the time for us.
Doug
I dont think he will forget about the ball bearings
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Old Feb 10, 2011, 05:02 AM
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Spain
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Foam gets the Bends

I guess this is a good place to ask....

I have just started cutting with my CNC machine

I put the foam on the table and started cutting. The foam did not move, so I guess I was cutting with Radiant heat. After a little while, the foam started groaning and sprang out of shape, but did not move on the table.

I attach a picture.

I did some searching and I understand that I need to put a LOT of weight on top of the foam.

What else can I do? When I cut manually, this never happened.
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Old Feb 10, 2011, 06:04 AM
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Originally Posted by Martin@ul.ie View Post
I guess this is a good place to ask....

I have just started cutting with my CNC machine

I put the foam on the table and started cutting. The foam did not move, so I guess I was cutting with Radiant heat. After a little while, the foam started groaning and sprang out of shape, but did not move on the table.

I attach a picture.

I did some searching and I understand that I need to put a LOT of weight on top of the foam.

What else can I do? When I cut manually, this never happened.
There are internal tensions in extruded foam. When you cut it, they are released and the foam may change shape. This highly depends on the foam itself and the way it was built. Depending on the provider, you may more or less this problem.

One way to solve this is to cut a small slice on the top and bottom.

Personally, I don't cut anymore extruded foam because of this and I prefer dense expanded polystyrene.

Gilles
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Old Feb 10, 2011, 07:22 AM
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Martin@ul.ie's Avatar
Spain
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Bendy foam

Thanks Gilles.

Will get a different foam to try the next time I go to the hardware store.

I tried slowing down by 25% and lowered the rene wire power by about 20%.
I put a LOT of weight on top.

Result was almost acceptable.

Strangely, when the cut was finished the block stayed flat. Looks like the heat allows the forces accumulated to distort the foam.

I will also try removing the top/bottom 3mm and see what happens...

Is there a particular brand of foam you use? Do you weigh it down?

Thanks
Martin
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Old Feb 10, 2011, 07:35 AM
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HI Martin,
Echoe-ing what Gilles said, when you cut extruded foam, I usually cut it to 5mm off the top, flip it over and then 5mm again off the top. This takes most of the stress out of the foam. That is why you do it in the first place to get rid of the stress. Aftyer you have shaved both sides a bitm when you cut your airfoils, it does not react that way as much, but still may pop up a bit. Practice with some scrap foam on smaller pieces so you don't waste your sheet size foam. Small slice on both sides, then cut it down to siz, then cut your airfoil. Nice looking table. What slides did you use?

Doug Blackburn
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Old Feb 10, 2011, 08:00 AM
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Originally Posted by Martin@ul.ie View Post
Thanks Gilles.

Will get a different foam to try the next time I go to the hardware store.

I tried slowing down by 25% and lowered the rene wire power by about 20%.
I put a LOT of weight on top.

Result was almost acceptable.

Strangely, when the cut was finished the block stayed flat. Looks like the heat allows the forces accumulated to distort the foam.

I will also try removing the top/bottom 3mm and see what happens...

Is there a particular brand of foam you use? Do you weigh it down?

Thanks
Martin
I don't have a particular brand. I am using white expanded polystyrene which is specifically made for foam cutting. Unfortunately, I don't know the provider, since it was given to me.

Gilles
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Old Feb 10, 2011, 08:03 AM
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Originally Posted by gm.cnc View Post
I don't have a particular brand. I am using white expanded polystyrene which is specifically made for foam cutting. Unfortunately, I don't know the provider, since it was given to me.

Gilles

BTW, have a look to my rafale in my blog http://blog.gmfcsoft.com/
and here : http://www.gmfcsoft.com/rafaleV2

It will give you an idea of the precision you can reach...

Gilles
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Old Feb 10, 2011, 08:19 AM
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Originally Posted by Martin@ul.ie View Post
Thanks Gilles.


Is there a particular brand of foam you use? Do you weigh it down?

Thanks
Martin
Martin, I'm not sure where you are located, but if you want to try dense(ish) expanded bead foam, you might be able to look for an architectural foam cutting service and purchase foam from them. Here in San Diego there is a place called Foamco that cuts columns, moldings and trim pieces for stucco or plastering. They have 8' by 8' by 20' pieces of 1, 2 and 3 pound/cubic foot foam that they will just slice off whatever size piece that you need.

Ward
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Old Feb 10, 2011, 02:18 PM
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Spain
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Originally Posted by Twinboom View Post
HI Martin,
Echoe-ing what Gilles said, when you cut extruded foam, I usually cut it to 5mm off the top, flip it over and then 5mm again off the top. This takes most of the stress out of the foam. That is why you do it in the first place to get rid of the stress. Aftyer you have shaved both sides a bitm when you cut your airfoils, it does not react that way as much, but still may pop up a bit. Practice with some scrap foam on smaller pieces so you don't waste your sheet size foam. Small slice on both sides, then cut it down to siz, then cut your airfoil. Nice looking table. What slides did you use?

Doug Blackburn
Thanks, I'll try that.

The slides are Bosch Rexroth.
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