cnc plasma stuff

[matttargett4]

hi guys,

im new here so forgive me if i talk rubbish! i am planning an 8 ft x 4ft plasma table, have done quite a bit of research an was planing to use igus w single rails for the x, with a rack and pinion drive next to it on both sides to try to combat binding, a 1.25mm pitch is planned driven by a 18 tooth spur on each side direct onto a 12nm stepper giving a minimum step of 0.112 mm or 0.0044" if i can do 200 steps / rev and @ 1000 rpm could reach 22.5m / min or 880 " / min. igus double rail for the y and z axis with a single rack and pinion drive with the same motor and spur.

does this sound remotely credible? feel free to tear it apart id rather find out from a group of experts than throgh expensive cock ups!. willl mach be good to run it?

thanks alot

matt

[Cartierusm]

I wouldn't use 1 rail I would use 2. The point of the rail is carry the weight of the axis, if I get what you're saying you're going to use the rack and pinion as the linear slide. I just don't think it would be that good. Now are you talking about the Igus slides that have the teflon inserts? If so they suck for linear motion I have a whole bunch of them I bought when first building my CNC. I tried everything and they just don't cut it. Plus them have plastic parts in them that some of the slag from the plasma and sparks might not like.