I've built a 4 axis hot wire machine you can see my build and plans at http://www.rckeith.co.uk and have used it to produce wings and fuselages. I don't really have a limit to the size of wing as the two towers can just be moved further apart. I usually secure them to a board to prevent them moving. I've found the best result are obtained with really thin wire( I think the size is on my website). If your wire is long then you may need to experiment with feeds and current as it may vibrate a little and give poorer results. The biggest challenge I've found is the software. Not much around for 4 axis hot wire so tends to be more expensive. I've spent more on software than hardware. I use Profili2 Pro and Dev Fus Foam but its a bit of a learning curve. Straight wings are fairly easy but tapered are bit more challenging. If you don't have positioned correctly in the machine according to the distance specified in the software the wing comes out larger or smaller. My first flying wing came out a bit smaller than I expected but it was a bonus because if flies absolutely fantastic. Hope that helps

Keith

Quote Originally Posted by Skipsoaring View Post
Hi there!
I will be building a 4 axis CNC hotwire maching for cutting cores for Radio Controlled gliders.
I am just starting the serious research (when I am not being seconded into the real world) and so far I'm thinking that due to my current space constraints I will make it so that it holds the foam vertically against the garage wall.
The machine size is still up in the air and will depend on the size of the blocks I can source. The largest wing panel I can see myself making is 1500mm, although being CNC made (accurately compared to wire dragged over templates/fences) I could make the panels in 2 parts as the majority of the wing panels would be 750mm.

I have a LOT to learn as I am trying to teach myself CAD (Onshape and Sketchup), am yet to learn anything about CAM and have always been petrified by Electrickery!!

I have chosen to build a CNC hotwire as it should be relatively simple and I want to build a CNC router next, having learned some lessons along the way.

The basic idea of the CNC Hotwire machine is to enable me to cut eliptical wing panels which requires independent movement of each end of the wire along the x axis and z axis (hopefully got them right from a gantry machine perspective)

The x axis travel shouldn't need to be more than 500mm and the z axis travel should be similar. I do need to figure out if I would need more though. If, for example, I was to cut a 750mm panel with an elliptical shape and the posts were 1500mm apart, the x axis travel would need to be much greater than if the posts were 800mm apart. Perhaps I need to look at designing my machine to have relocatable rails for the x axis?

I understand that from a construction point of view, my two machines will be worlds apart, the lessons I'm hoping to take to the next build will hopefully be software, electrical and generic.
Anyway, gotta go do the school run.

Cheers
Clayt