Hello everybody,

This is my first post on this forum, but I've already learned a lot from it. Anyway, here is my story/idea.

I started building a cnc from MDF in january. I've completed it about 2 months ago or something like that. It works fine, but it is still made of wood, so speed and precision are still limited. I've used skatebearings for the linear rails which will do for now, but I think they still have a lot of play so that is not very precise. I've used normal leadscrews in combination with nylon self-tapped bolts. Pictures and a test video can be seen here: http://www.modelbouwforum.nl/phpBB2/...=asc&&start=90
This all works good, and so now I am shure that it works, that I am able to build a cnc. But now, I want more.

I would like to build a new machine out of 3mm steel. I want to draw it up in solid edge and then take the plans to the laser cutter and have them cut out. I want to paste the pieces together with loctite 330, also used in the zoltar machines and the "tron" cnc. The steppers I have now are 2 times 1.5Nm for de x and y ax, and 1Nm for the Z ax. I am using the nc step 3D card to controll them and a 42V power supply to feed the steppers. I would like to use these steppers on the new machine.
Som specifications for the new machine:

-cutting area: 1000mmx500mm or 1000mmx800mm. The last one would be better as I could lay down complete sheets of depron(kind of isolation material to make rc airplanes) on the cnc, but if it gets too expensive, I would stay with the 500. 1000mm is just the length of a sheet of balsa.

-use trapezium leadscrews. Anyone knows some cheap but good websites of stores in Europe?

-It has to be able to cut balsa wood, triplex, plexiglass and other harder plastics. Would cutting metal also be possible with this machine?

-Linear motion: use igus products, because this is relatively "cheap".
I do need some advice on this. Can anyone tell me what products to use on what ax? I thought to use:
>the single rail, dia 20mm on the x-axis(should I use one or two on each side? so do I need 2 rails or 4 rails for the x-axis?)
>dubble rail 80mm wide (16mm dia) on the y-axis
>dubble rail 40mm wide (10 or 16mm dia ?) on the z axis.
(products can be seen here: http://igus.bdol.com/show_dw.asp)

I someone has some experience or tips, please let me know so I can start drawing in solid edge. The key parts now are the linear slides. If you have a better alternative on the igus products that also is as affordable, please let ma know so we can discuss it here.

thank you, and sorry about my english

Mathias