2 lb EPS Foam Carving- Bits, Feeds, Speeds?

[SarahRay]

Hi There and thanks so much for any advice you can offer:D

I'm cutting a fairly large 3D shape (on a tight deadline!) that has a height of 12". I have sliced the model in Apsire and plan on doing it in 4 3" thick slices.

Looking for feeds and speeds, and any suggestions of how to get this done ASAP!

Only 1/2 of the model will fit on the 4x8' bed, so it has been also been split down the z axis. I anticipate a busy week next week!!

Ordered these bits which I hope will suffice:

Amana 46277 Solid Carbide Foam Cutting Up-Cut Spiral 3/8 Dia x 4 Cut Height x 3/8 Shank x 6 Inch Long Flat Bottom Router Bit

Amana Tool 46032 Solid Carbide Foam Cutting Up-Cut Spiral 1/8 Radius x 1/4 Dia x 2-1/4 Cut Height x 1/4 Shank x 4 Inch Long Ball Nose Router Bit

Thanks so much!

33103

[knight_toolworks]

the limit is your machine. the z axis of course is the biggest limit. your bullnose can cut 2.5" in a pass so if you can just remove enough on the roughing pass so it does not have any foam deeper then that you can do it in all in 3d. that will save a huge amount of time. if you slice it to get 2.5" thickness you can do it all with the bullnose and save a lot of time.

[SarahRay]

Thanks for the reply. Do you have any recommendations on feed and speed?

[knight_toolworks]

6 to 8 ips the z is the limit I think 6ips is the max. not sure of the rpms but its not critical on foam so keep it low to keep the heat down. the larger the stepover you can manage will save a huge amount of time. but saving the roughing toolpath will really save some time.

[pro70z28]

I've cut a fair amount of HDU and also pink & white foam from the big box store with 1/2" bull nose. Single finish pass is all I used. In the early days I even ground a bull nose end on a 1/2" drill bit with the bench grinder (poor man's router bit) and it worked fine on foam also.