Foam XL hot wire cutter

[Boyan Silyavski]

yes, there is absolutely no point of going with 12 size rails given the size of your extrusion. 20 size will be best. 15 size may save you some $$

i went with screws as on that length price was same, but i had to go with bigger belt, at least Hdt3 15mm wide, which would mean bigger motors, bigger drives. And at the moment i am hoping to drive all with 30 euro ramps 1.4 and drives, 4 motors 10 euros each and the DEVFoam CNc which seems best for the purpose

[charlieuk]

I'm probably not actually even going to make mine cnc to start with, until I decide to go 4 axis there is not a lot of point as any wings I would need are tapered and then I would probably just build a small machine for them. most of what I do is just cutting square blocks and I can do that without so will just have some sort of motor and gearbox and some basic controls. I also decided to make the machine the full 6meters ( full length of alli) so that means ether belt or rack.no I do have some spare rack here that was left over that I could use but its going to be hard to get it to work without having it on booth sides so I'm going to probably have to use a belt to drive that.

[Boyan Silyavski]

What would you cut at 6meter length? i mean, arent all foam blocks 2mters long?

if i was going to make such a serious machine i would have probably used belt on belt drive which will again simplify things. In that scenario there is no need of very big size belt as the stretch is "none"

[charlieuk]

the same thing stuff that I cut on my 6m long cnc. The blocks I normally use are 16' x 4' x 2'. belt on belt is a good idea I will just have to figure where is best to place it, it will probably mean that I will need to have one ether side and two separate motors but that shouldn't be too much of a problem. unfortunately I cant see myself being able to join the gantry underneath due to the length and trying to support the frame.

[charlieuk]

so I remembered I had this idea a while back but forgot and that was to make it so that in the future I can add cnc and convert to 4 axis. It wont really add anything to the cost of the frame but would require two extra lengths of rail and two more carriages so I will at least do the frame like this from 40x40

[charlieuk]

thought I would get some quotes for rails, china want £638 plus shipping for 15m of linear rail and 6 carriages odiously its not going to be real hiwin were as cnc4u is £989 for the same but real hiwin. This is just to do a single rail each side for two axis which would obviously be nearly double to do 4 axis and have the two rails each side.

ether way I think I may be back to looking for possible cheaper solutions, I was wondering about round rails if I did the two rails each side but not sure there would be that much saving in cost.

[Boyan Silyavski]

On such a big machine round rails-No. What about exploring the 3d printed +Delrin balls scenario? It will be the best pricewise.

[charlieuk]

I'm thinking maybe these and 3 per side for the main axis and maybe stick with the linear rail for the vertical. It sucks I really hade to cut corners but for the amount it will be used I cant justify 1k on linear rails.

other wise I guess It would be using some sort of bearing carriages to run on some steel guides. like cnc router parts do.

[Boyan Silyavski]

I'm thinking maybe these and 3 per side for the main axis and maybe stick with the linear rail for the vertical. It sucks I really hade to cut corners but for the amount it will be used I cant justify 1k on linear rails.

other wise I guess It would be using some sort of bearing carriages to run on some steel guides. like cnc router parts do.

Most probably that rollers will not do. Inside there must be angular contact bearing or a bearing with no clearance. I am 99% sure thats not it. Plus they need to be turned, not molded plastic

[Clive S]

Charlie I think you need to be realistic regarding the tolerances here, I don't know but surly you won,t need more than a 1mm for cutting foam you are going to get sag in the wires etc. I think something like what you are planning should work ok.