Recently my son-in-law said he needed a way to cut large letters and shapes out of thick styrofoam. Coincidentally there was a recent video of a really neat hot-wire machine which strongly suggested I could functionally duplicate it using TWO of the ERC TimSav needle-cutting machines, recently released by Edward Chew as a kit. TimSav is an inexpensive “minimalist” 2-axis X/Y + servo-Z needle-cutter machine and quite the hit with RC’ers who are getting tired of hand-cutting foamboard for their airplanes. I was a “consultant” on the project and got “dibs” on one of the first machine kits shipped out.
By ditching the servo-Z and needle-cutter and standing the machine on edge, I had everything needed for one tower of a two-tower hot-wire machine, similar in function to the Mechatronics machine. TimSav is such a simple machine, I was able to build the second tower out of my parts stash. I mechanically tied them together with a couple of cross-pieces and left a 10" or so gap between, where the foam work-piece stands on edge, and a length of nichrome wire affixed to the carriages of the parallel towers. KISS is still king at my house… and this is a simple two-axis beast. No independent towers, no fancy tapers for me… the towers are “slaved” together with the corresponding motors wired in series, ala MPCNC, so just straight-through cuts.
Here it is in action, at actual speed, and a couple of “finished” product…
I’ve called it a TimSavX2 hotwire machine and the small penguin shape was cut from 2" thick styrofoam. Using 100mm section of 30 AWG nichrome wire (6.5 ohms/ft) and 1.5 amp current I was able to set a feed rate is 1000 mm/min without too much drag. I’m running Grbl 1.1 firmware on an inexpensive Eleksmaker Mana SE v3.2 2-axis CNC controller.
There was a good bit of flex at the tops of the towers and the hot wire wasn’t kept in tension at max Y extent. But I also didn’t want a hard attachment of the towers… to keep the machine from destroying itself if the towers ever got out of sync. So, I devise a little spreader bar composed of two printed Y-/U-shaped pieces that simply slip onto both ends of an appropriate length of skewer and the tension of the spring-loaded hotwire keeps it in place between the tower tops.
I’ve never felt I was “fast”… just the opposite. But I’ve got no deadlines and have full-time to spend only on projects that pique my interest… and I’ve done enough of this stuff I don’t make as many show-stopping, dumb mistakes as I used to. Some of it is also a “revisit” of things I’ve already done at some time or another (like the r&p stuff). And I’ve got a pretty good stash of parts and dismantled/obsoleted machines to pull parts and, sometimes, entire sub-assemblies from. And my customer base is tiny… so nothing has to be bullet-proof, extensively tested, and/or made production ready. It’s a tough life, I’m tellin’ ya…
That thing looks like it works great!
Can’t think of anything I would need it for, but still interesting to look at.
That beep (in the video) wasn’t your smoke detector was it???
No… wasn’t the smoke detector. I have one of those really neat Charsoon Anti-Matter 250w/10a battery charger units from back in my RC flying days… that has a foam-cutter mode and timer. When actively outputting power, it beeps periodically… presumably to let you know it’s active. Had it set to 20 minutes from last use. It may have a mode to turn the timer off and it’d stop beeping? Really doesn’t bother me too much, though…
I had a chance to see this thing up close this afternoon, thanks for taking the time David. It’s a pretty slick machine for sure.
It was a pleasure meeting you and I know it won’t be the last time you and I talk machining, tech and BS. Sorry I had to cut it short though. And thanks for the 3D parts, they fit well on the 611!
One of my favorite characters and test subjects! Hot-wired on TimSavX2 hot-wire foam cutter. Feedrate is 1000 mm/min and ~100mm of 30 AWG Nichrome wire (~6.5 ohms/ft) with 1.5 amps passing through it… temp (from charts) is in the 600 - 800 degF range.
This is awesome. I would place a pouring sprue on top of his head, bury him in a bucket of play sand, and then pour some molten aluminum on it.
I’ve been doing lost foam casting for a few years now and the thrill i get when i pull the part out of the sand never gets old. This kind of machine would make it just that much more fun.
A few years ago, I was right there with you. Sadly, I’m now relegated to doing only the “light stuff”… and don’t have the strength, energy, or shop setup left to do even modest manual labor. And while this machine was too late to the party for me… maybe it’ll help some of you stronger, more energetic folks take it to the next level. And I’ll then live vicariously through you…
I built an aluminum forge 2 years ago but never completed it. It’s sitting in my garage attic waiting for the day when I have the space (land) and the time to complete it and use it. It’s about 95% complete.
SIL had requested some “donuts” hot-wired for a decorative tire-swing for the children’s activities room redecoration project at their church building. Finally got TimSavX2 uncovered and ready to cut again, found a couple of suitably-sized 2" construction foam pieces, and prepared the gcode for the tire laminations.
Cut 4 tire laminations total. Looks to me as though this could be a “rubber ducky” if he decides to change his mind
He’ll be doing further sculpting and painting after glue-up so the rough spots and through-cut to the center won’t be a problem at all…
This is possibly my last hot-wire project with TimSavX2. SIL is nearing completion of the large foam project he signed up for and since I have little need of such a machine and it takes up quite a bit of room… I could dismantle it and have the two TimSav CNC machines to play with again.
