[islamCe]

Iam newer in the cnc world and i made a design for my project(cnc plasma).
Because it is my first experiment, i want to know ur opinion about what i did
and i have some question:
1- is that design is suitable for cnc plasma?
2- is ball screw with lead 5mm at the horizontal and vertical axis is suitable for cnc plasma?
3- is that design will be accurate than rack and pinion transmitting?
note that : the photo of project in the attachment

[xalky]

1- is that design is suitable for cnc plasma?

I would change the drive system to either a rack and pinion or Belt drive system.

2- is ball screw with lead 5mm at the horizontal and vertical axis is suitable for cnc plasma?

Ballscrew is not good for plasma unless you plan on installing a bellows to enclose the ballscrews. Plasma dust will sieze up the ballscrews quickly.


3- is that design will be accurate than rack and pinion transmitting?

Ballscrew might actually be more accurate, but it won't be accurate for long.

This is why most plasma table designs use a Rack. I built my table using belts for the same reasons. Belts were cheaper and so far they have been doing really well. The belts are also very quiet.

The best drive ratio for a servo driven plasma table is 1" of table travel per 1" revolution of servo motor.

[jimcolt]

Actually ballscrews and lead screws are used on a few small cnc plasma tables....the ballscrews need to be protected from direct hits of the sparks...but usually are not completely enclosed in a bellows.

Ballscrews generally are not used for 2 reasons:

1. They are very expensive compared to rack and pinion drives

2. They are difficult to build in lengths over about 8 feet....the ballscrew diameter must get larger (to compensate for torque twist). Wih a rack and pinion you simply add more rack.

Jim Colt

[islamCe]

i surprised to read that words,
this is the first time i heard that the ball screw is affected by dust of the plasma spark.
i saw people used ball screw on them plasma machine like this video:[ame=http://www.youtube.com/watch?v=dkwa2O3BZsQ]Home Made CNC Plasma Table $300 - YouTube[/ame]
But there is way to protect ball screw from the dust of plasma spark,
what is this way?
i heared that the rack and pinion have a large backlash than ball screw.
is this true?