[captahab]

I just completed (more or less) my first CNC hotwire machine that I built for cutting out cores for my Long-EZ homebuilt airplane. It has all custom designed and built electronics based on L297/298 ICs. I built my own interface board designed to work with Mach 2 which I thought used a protocol standard to most CNC machines of any type. I've been using Foamworks to do testing so far and it works fine but doesn't allow for fine tuning on such things as backlash compensation or hotwire heat control (on/off only). I wanted to try Gilles Muller's software but it seems to use a much more complicated interface. I don't really want to build another interface board for a program that I may not even like.

My questions are:

1.) Are there any other good programs available that I could try?

2.) Is there some simple way to get Gilles Muller's software to work without building the MM2001 controller?

While I'm at it,

3.) What is the best wire diameter to use? I'm using .032 stainless steel safety wire as recommended in the Long-EZ plans but it seems a bit large.

Thanks

[GAWnCA]

Sounds like you and I are in the same fix when it comes to controlling the hotwire. I bought Inconel X750 .012" from http://webpages.charter.net/mnemesh It's not cheap but from all the research I did (before spending 50 cents a foot) it should be the best.

As for your first question, I think you've got the best, Foamworks does a good job of moving the gantries and Dave is darn good at answering any questions you may have. MACH 3 is also very good for the money and Art is good at support as well.

If you come across a good hotwire controller let me know and I'll do the same for you.

I just completed (more or less) my first CNC hotwire machine that I built for cutting out cores for my Long-EZ homebuilt airplane. It has all custom designed and built electronics based on L297/298 ICs. I built my own interface board designed to work with Mach 2 which I thought used a protocol standard to most CNC machines of any type. I've been using Foamworks to do testing so far and it works fine but doesn't allow for fine tuning on such things as backlash compensation or hotwire heat control (on/off only). I wanted to try Gilles Muller's software but it seems to use a much more complicated interface. I don't really want to build another interface board for a program that I may not even like.

My questions are:

1.) Are there any other good programs available that I could try?

2.) Is there some simple way to get Gilles Muller's software to work without building the MM2001 controller?

While I'm at it,

3.) What is the best wire diameter to use? I'm using .032 stainless steel safety wire as recommended in the Long-EZ plans but it seems a bit large.

Thanks

[captahab]

Thanks for the response. I made that post almost a year ago now and you are the first to respond. I also bought come inconel wire from the same person because it seemed to be the best deal. I also figured out the whole interface board for GMFC and got it to work with my own electronics with minimal additional components.

I've not messed with my hotwire project for some time until lately. For the last week or so I've been working on the last part of my machine that I've been unhappy with; the wire holding and tensioning mechanism. This has turned out to be a far more complicated problem than I had imagined.

What exactly do you mean by "hotwire controller"? The software, the motor driving hardware, or the wire heat electrical device?

[GAWnCA]

HA HA HA I didn't even notice the date. My problem is getting the electrical for the hotwire heat control. How about some pictures of your machine?

Thanks for the response. I made that post almost a year ago now and you are the first to respond. I also bought come inconel wire from the same person because it seemed to be the best deal. I also figured out the whole interface board for GMFC and got it to work with my own electronics with minimal additional components.

I've not messed with my hotwire project for some time until lately. For the last week or so I've been working on the last part of my machine that I've been unhappy with; the wire holding and tensioning mechanism. This has turned out to be a far more complicated problem than I had imagined.

What exactly do you mean by "hotwire controller"? The software, the motor driving hardware, or the wire heat electrical device?

[captahab]

Hmmm, I replied earlier but it doesn't seem to have posted. Here goes again....

There are some photos on this site:
http://members.cox.net/ahabsworkshop/CNC.htm

So far I've just been using a transformer/rectifier with a resistor to vary the current and thus the heat of the wire. I just bought some components to build a PWM heat control but I haven't built it yet. I think it would be relatively easy to build a computer controlled wire heat control as well but I haven't needed it yet.

[GAWnCA]

Hmmm, I replied earlier but it doesn't seem to have posted. Here goes again....

There are some photos on this site:
http://members.cox.net/ahabsworkshop/CNC.htm

So far I've just been using a transformer/rectifier with a resistor to vary the current and thus the heat of the wire. I just bought some components to build a PWM heat control but I haven't built it yet. I think it would be relatively easy to build a computer controlled wire heat control as well but I haven't needed it yet.

I'll have to post some photos of the construction of my machine. I am finding that drawer slides, while may be nice for the first time builder, they are too loose. What size transformer are you using and how about a simple drawing of what you are using to heat the wire.

I made my first cuts last night (freehand) just to see how the wire worked. That inconel wire is really nice stuff. Worth every penny. If you ever decide to build the board to computer control the hot wire I would sure be interested.

Great work and I'm glad I've found someone else taht will talk hotwire and not just CNC machining.

[captahab]

Yeah, I was totally disappointed with the whole drawer slide thing. What do you want to make with your machine? I wanted to be able to use mine to build full scale homebuilt airplane wing cores so I needed a pretty big machine that was capable of a high degree of accuracy. Most everyone else I've read about or talked to are making model wings. If you want to find some more people to discuss this with, check out this forum:

http://groups.yahoo.com/group/CNCFoamcutters/

and this one:

http://www.rcgroups.com/forums/showthread.php?t=469391

For a wire power source I just used a Wal-Mart 12V battery charger. I made a simple variable resistor by wrapping a piece of stainless steel safety wire around a board. I can vary the resistance by changing where the leads are clipped. I used the same thing for my homemade TIG welder. There are a couple of photos on this page: http://members.cox.net/ahabsworkshop/TIG.htm

It's pretty quick and dirty but it gets the job done. I want to build a more sophisticated design using pulse width modulation and/or make it computer controlled. By looking at the schematic for the mm2001 board, the computer controlled heat portion looks pretty simple. I'll probably tackle that when I get my wire holder completed.

[GAWnCA]

Yeah, I was totally disappointed with the whole drawer slide thing. What do you want to make with your machine? I wanted to be able to use mine to build full scale homebuilt airplane wing cores so I needed a pretty big machine that was capable of a high degree of accuracy. Most everyone else I've read about or talked to are making model wings. If you want to find some more people to discuss this with, check out this forum:

http://groupyahoo.com/group/CNCFoamcutters/

and this one:

http://www.rcgroups.com/forums/showthread.php?t=469391

For a wire power source I just used a Wal-Mart 12V battery charger. I made a simple variable resistor by wrapping a piece of stainless steel safety wire around a board. I can vary the resistance by changing where the leads are clipped. I used the same thing for my homemade TIG welder. There are a couple of photos on this page: http://members.cox.net/ahabsworkshop/TIG.htm

It's pretty quick and dirty but it gets the job done. I want to build a more sophisticated design using pulse width modulation and/or make it computer controlled. By looking at the schematic for the mm2001 board, the computer controlled heat portion looks pretty simple. I'll probably tackle that when I get my wire holder completed.

I have a very simple wire holder... I simply took 2 eye hooks and screwed them into the lead nut (made of UHMW) and then connected a spring to that. Smees to work fine. WHat is your's looking like. TIG welder, what do you use it for?

[GAWnCA]

Will your TIG welder do aluminum? I'm a member at both of those groups.

[captahab]

I used a similar wire holder to that to begin with. It works fine for cutting things with little or no taper but not so well for things with a lot of taper like airplane wings. My machine needs to allow the wire to change length up to about 20" at the maximum. Also, I don't like it when the tension changes all the time. With the small diameter inconel wire it will break easily when you get too much tenson on the spring. I'm building a bow that will hold the wire and keep the tension constant. The machine will hold the bow fixed at one end and allow the other end to slide back and forth so the length can change.

I used my TIG welder to weld all the pieces of the machine together. I originally built it to weld thin stainless steel sheet metal for experimenting with pulse jet engines. No, it won't weld Aluminum, it's just a DC machine. It will weld just about anything else though. Now I have a Harbor Frieght TIG welder which works pretty well (still no aluminum though). My homemade one actually works better for really small stuff but the Harbor Freight one works better for thicker stuff.

[GAWnCA]

I have seen where some people have put like a pully wheel on one side of the cutter and then hung a weight from the end of the wire and that would give you as much length as you need. I may try that and see how it works. as long as the pully and the mounting bracket are mad of metal the power connection could stay in a fixed location.

I may give your TIG welder a try one of these days. Harbor Freight has a dual MIG welder that will feel aluminum for welding. It's a LOT cheaper than a Miller MIG that does the same thing. Sometimes on ebay you can find the spool feed gun for a reasonable price.

I used a similar wire holder to that to begin with. It works fine for cutting things with little or no taper but not so well for things with a lot of taper like airplane wings. My machine needs to allow the wire to change length up to about 20" at the maximum. Also, I don't like it when the tension changes all the time. With the small diameter inconel wire it will break easily when you get too much tenson on the spring. I'm building a bow that will hold the wire and keep the tension constant. The machine will hold the bow fixed at one end and allow the other end to slide back and forth so the length can change.

I used my TIG welder to weld all the pieces of the machine together. I originally built it to weld thin stainless steel sheet metal for experimenting with pulse jet engines. No, it won't weld Aluminum, it's just a DC machine. It will weld just about anything else though. Now I have a Harbor Frieght TIG welder which works pretty well (still no aluminum though). My homemade one actually works better for really small stuff but the Harbor Freight one works better for thicker stuff.

[IAD]

Quick question: Does MACH (2 or 3) have support for hot-wire machines?

~Luke

[GAWnCA]

I don't think it really does. I guess you could make it work, but it sure is overkill. Try http://gm.cnc.free.fr/en/index.html I've got a firned building a LONG -EZ plane and he is cuttin ghis foam using this software. Gilles gives pretty good support. You can download the Pro version and run it for 30 days and then if you like it, it's about $200.00 USD to buy.

Quick question: Does MACH (2 or 3) have support for hot-wire machines?

~Luke

[IAD]

I see. The reason I was asking was because I'm building both a router and a (have built) a hot-wire setup, and figured driving both with the same software package would be nice. I've used GFMC a bit, and I do like it, except for the price-tag.

~Luke

[jetski]

I used a NiCrome wire with great results on a manual unit. I dont remember the dia.

[flyboy1015]

I saw a few posts back that Captahab wanted to build a heat control. I used a power transistor that I had in my box and then used a potentiometer to adjust the amps. It's very simple and pretty effective. If you wanted something a little more complex, you could add an LED bar (LM3914) driver to make a meter with LEDs to monitor the voltage/current.

[jetski]

First you go to Wal-mart and pick up a cheap batt. charger. Then you hook the positive up to one side and the negative to the other end of the Ni Chrome wire and to make it hotter you slide the one closer and to make it not so hot you slide them apart. Oh there is an expansion problem, so I put a small spring that will stretch about 3-4 inches to keep the slack out. I would bet you could use a HO train trans former and a few test clips. Just depends of the amps you need to heat the wire to the temp you need. I was cuttin 6-8 inch styrofoam for a roof. Now the only foam I cut is off the top of a tall beer glass. Guiness need a truck jump start wire set up.