Alright! Several of you have already spoken up so here's the post with all the links I promised and a bit more information about both my foam cutter and the CNC machines I've used during its most recent development. I've been using this method for several years now to machine-cut my planes out of fanfold foam insulation sheet and DollarTree foamboard. Never again will I hand-cut designs. I know it appears a bit crude but I have cleanly cut "miles" of foam using this method with minimal fuss.
Basically my foam cutter is a very fast reciprocating needle... like a sewing machine. The needle is formed from a length of 0.025" music-wire and attached to a small ball-bearing mounted eccentrically on the flywheel. The flywheel is mounted on the shaft of a 2826/2822 brushless motor (with ESC and servo tester) and spun at 8000-10000 rpm, resulting in a stroke/perforation per revolution. A feed rate of 600-1000 mm/min yields 10-15 strokes/mm and cleanly cuts DollarTree foam board (paper on), blue-cor fanfold foam, etc.
In the past couple of months, I have built three of Ryan "Allted" Zellars' fantastic Mostly Printed CNC (MPCNC) machines for myself and a couple of friends and it is the perfect vehicle to mount a foam cutter and cut sheet foam materials (DTF, blue-cor FFF) accurately and cleanly. The foam cutter itself can be built and adapted to your CNC machine for less than $20 worth of parts (less if you're a scrounger). But if you also need a CNC machine -- and if you (or a friend) are "handy" and could tackle a large erector set project -- you can build a complete 48"x48" (or smaller/larger) MPCNC and foam cutter for less than $500 (<$300 if you can 3d print) and a weekend or two worth of time. It is easily IMHO the most flexible and economical way to get into CNC at the current time -- even if you have to buy the hardware and plastic "bundles" from Ryan's website. I'm not at all affiliated with Ryan or MPCNC... I'm simply an old retired engineer who appreciates good engineering when he sees it.
If you are interested in building one (or all) of these for yourself, please check out the links below. I'll continue to monitor this thread, answer questions, and further interact with folks here but rather than repeating everything I'm providing links to threads/sites that deal with the active design/development of this foam cutter and Mostly Printed CNC. Please check them out.
Foam Cutter design/development --
A fairly lengthy thread featuring brushed-/brushless-motor versions of the foam cutter, a Mostly Printed CNC (MPCNC) build log, user build(s), and general DTF cutting thoughts:
http://www.rcpowers.com/community/threads/mostly-printed-cnc-and-cutting-foam.18808/
User build(s) and further needle guide development:
http://openbuilds.com/threads/brushl...eet-foam.5862/
Universal MPCNC quick change/release system for assorted tools (including foam cutter) and user build(s):
http://www.vicious1.com/forum/topic/...unting-system/
http://www.vicious1.com/forum/topic/...s-foam-cutter/
All 3d-printed versions/parts --
Brushed motor versions:
http://www.thingiverse.com/thing:1138627
Brushless-motor versions:
http://www.thingiverse.com/thing:1211039
Universal MPCNC mounting system, including foam cutter head:
http://www.thingiverse.com/thing:1245848
Mostly Printed CNC:
http://www.thingiverse.com/thing:724999
http://www.vicious1.com/specifications/
etc...
Please feel free to join in the conversation and/or ask questions.
-- David Johnson (aka "dkj4linux")