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Discussion in 'Other Builds' started by Gino Lanzi, Feb 6, 2017.
A 2 independent gantry affordable hotwire machine.
Gino Lanzi published a new build:
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The kerf is about 1mm and relatively consistent. By its nature a hotwire machine is not a precision machine. If you allow the wire to touch you'll get drag that will really hurt accuracy. You can't tention the wire enough to prevent drag without prematurely breaking the wire. I suppose you could turn the temp lower and slow the machine enough, but it would still be essentially the inertia applying the resistance. I've run hundreds of feet through my other machine and the nema 17s are sufficient. Of course that machine uses 23s, but I ran it on 17s for some time while trying to source .9 degree 23 steppers.
I have no experience with hot wire machines, so pardon the ignorance of the question. What are these used for?
The are used primarily to cut polystyrene foam. Hobbyist use them for foam wings and fuselages and other things like crafting. Commercially they have many purposes such as architectural moldings and custom packaging.
I have been thinking about something like this where you can easily move the machine around a larger piece of stock so the actual build platform wouldn't have to matter.
Jel111, it will work well for that purpose. Expect to see a video of it actually cutting something soon.
What kind of wire are using to cut the foam? I have been using iconel on a hand held bow type cutter.
Hi Thunder, Most of the time I use 28.5 gauge rene wire. I occasionally use 25 gauge rene wire for certain applications, but it is rare. I buy it at Jacobs online. There is a lot of good information on their site as far as wire and required power. Personally I haven't used iconel but heard it is very good like rene wire they are both super alloys.
Can I do this letters with that CNC? & where I can find foam blocks locally?
This is my first time trying to do something like this, & I need A LOT of advice. Thats why Im here, perdon my ignorance.
Thanks in advance!!!
Yes, the "L", the "V" and the "E are easy cuts. The "O" has two options: opt one is easiest but requires the wire to pass through the body of the "O" to cut out the center cavity, leaving a kerf, which can easily be glued back or pinned together, if objectionable. Opt two requires drilling a hole through the the center of the "O", then pulling the wire through that hole, reattaching the wire, cutting the center out, then detach wire and pull back out, then reattach and cut the outside. Opt two is not as complicated as it seems and results in a much cleaner "O". Care must be taken, not to allow the block of foam to move as you attach, detach and reattach the wire. I stick the block of foam down with two or three dabs of hot glue, then place a weight on top, then place 4 strips of tape on the table/bed that represents the perimeter of the foam block. A bit of over kill but if the block of foam does get bumped and moves you need to be able to relocate as close to original position. Most of my parts are for aircraft and architectural customers and have to be pretty precise. Hint, when you place the block of foam with hot glue, put small pieces of masking tape on the table, then put the dabs of hot glue on the tape, before setting the block of foam, makes clean up much easier. Parts without a center cut or cavity, I generally just weight down the foam against a cleat fastened to the table that is parallel to the wire; i.e. a brick on top and a brick against the opposite side, parallel to the cleat.
I am in South Florida. When I first got started, I contacted Carpenter foam in North Florida, as they actually cast/manufacture the huge billets of foam. They were not interested in selling me a couple of 1ft X 2ft X 4ft blocks, as they have minimum order requirements. They did however give me a list of some of their customers near me that would re-sell small quantities to me. A few were not receptive, or just did not want to bother, but after about an hour on the phone, I had two peeps that would sell small quantities to me. I now buy it by the container load, direct, but that took a while, logistics of cash flow and storing that much foam, but much more economical. Just a note, make sure you specify "VIRGIN" clean foam, no re-grind and no bits of trash as this will "F" with your wire, resulting in a bad part. There was one guy near me that uses blocks of foam for flotation on docks, his foam had re-grind in it, and what appeared to be whatever was swept up on the floor. It did not matter to his application but was worthless to mine.
Hi Djruco, Yes the machine is capable of cutting the letters. Thunder1911 gave you an excellent reply as to how it is done. As far as sourcing foam, I buy my foam from Carpenter as Thunder1911 does, but I have use for the larger quantities as he does. Their website is carpenter.com. Try doing what Thunder did and contact them to see if anyone in your area will sell you smaller quantities. I haven't updated this project in a while because of other more pressing matters, but the machine is done and operating. I want to do a couple videos of it soon and one of them is going to be cutting a coca cola logo, so that one should be interesting to you. I am also planning to do one that cuts a square on one end and a circle on the other to demonstrate the independent axis. Hopefully I'll get them posted within a week or two. I watch this thread even when I'm busy so feel free to post questions.
WOW. This is amazing, how quick response I have from both of you. Excuse my english (not my native language), I was trying to go the cheaper way in build my CNC DIY, but now I believe Im going to go the fast way & get the kit from here Openbuilds.com, just because of the help Im going to get with all my projects, like you guys just did & less than one day, even do this is an old post.
Im a DJ & I have my wife helping me & adding her hobby/business together which is decorations & the first project is that exactly the LOVE table letters, which is hot right now for wedding events.
I'll keep you post with the updates. I'll contact carpenter.com to see if they have any vendor near me that can sell small blocks. Thank you again Thunder911 & Gino, you guys rocks!!!
Looking to see those videos Gino!!! As I said before, basically my CNC Hot wire will be for doing anything related to decorations (for now), & that Coca Cola logo will be a plus, I could market to signs companies too. Great!!!
Hello Gino, I know this is an old post but I am so excited with this project, please post more videos and details on your construction, I would love to be able to replicate your work.
I just saw OpenBuilds post this on their Instagram. I have been meaning to build one of these as well. I am curious as to if you have used it as an actual 4 axis machine? You mention it being 4 Axis, but all you examples are 2 axis (pairs of coordinated axis).
I am curious as to if devfoam can put out code for 4 independent axis (to do tapered wings etc.). I am also curious if you went this route how you compensate for the changes in wire length while maintaining constant tension. Those considerations have been my big barrier to get going on it.
I have not used this particular machine to do 4 axis, however; I did build a bigger more commercial machine that, while much more robust, operates on exactly the same principal. One of the first things I cut on that was a sample file that was a 4 axis wing taper and it worked beautifully. A spring tensions the wire and you can move the 2 axis independently within reason. If you wish to move them far apart then you will need to devise a spooling type wire feeder to outlet and uptake wire as necessary. You will also need to choose a power supply that can be current fixed. It will need to variably increase and decrease the voltage to maintain a constant current to the wire. In practice this is not to difficult to accomplish. You can find boost converters that provide constant current.
Thank you for you're reply. What software did you use to create the tapered cut code?