I am planning to build a very large CNC plasma cutting table for cutting
plates of 6000x2000 mm metric, so about 20' by 7'
Anyone know which company supplies rails and screws that long?

On Sun, 20 Feb 2005 23:35:39 +0100, "John Smith"
wrote:

I am planning to build a very large CNC plasma cutting table for cutting
plates of 6000x2000 mm metric, so about 20' by 7'
Anyone know which company supplies rails and screws that long?

Not exactly high precision, but I once saw a rig for cutting big
sheets of architectural lucite that used a skillsaw mounted on a
slowed-down garage door opener.

"John Smith" wrote in message
...
I am planning to build a very large CNC plasma cutting table for cutting
plates of 6000x2000 mm metric, so about 20' by 7'
Anyone know which company supplies rails and screws that long?



What you are building has been done before other than the width and length.
http://www.lockformer.com/pla.html
We have two plasma tables where I work, neither of them have screws to run
the carriage, just motors with drive wheels and sensors so it knows where it
is.
Think DRO.
Greg

"John Smith" wrote in message
...
I am planning to build a very large CNC plasma cutting table for cutting
plates of 6000x2000 mm metric, so about 20' by 7'
Anyone know which company supplies rails and screws that long?

elevator rails are pretty long

In article ,
says...
I am planning to build a very large CNC plasma cutting table for cutting
plates of 6000x2000 mm metric, so about 20' by 7'
Anyone know which company supplies rails and screws that long?



How accurate? For moderate accuracy I haven't found anything that can
beat the price of the timing belt systems from Item. I'm building a
machine right now that has a gantry positioner with a 2.5m stroke. About
$2000 for all the components for one axis, not including the drive and
controls.

http://www.itemamerica.com/

If you need very high accuracy, IKO, THK, etc., will supply their linear
rails jointed to be spliced in any length you specify - at a hefty
price.

A 6m lead screw is not a trivial undertaking, particularly if you
require high speeds and/or accuracy. A timing belt drive would be much
easier and cheaper. It would be easier to make recommendations if you
specify speed, accuracy and loads.

Ned Simmons

"John Smith" wrote in message
...
| I am planning to build a very large CNC plasma cutting table for cutting
| plates of 6000x2000 mm metric, so about 20' by 7'
| Anyone know which company supplies rails and screws that long?

Have you considered 80/20 tubing by Bosch? This stuff is usually used
for framing and such but it also has excellent applications for moving parts
of good precision. Precise, strong as hell, and easy to work with. You can
shim to get even tighter precision. You can have Bosch work out the design
for you or you can do it yourself. I'm in a shop at work now that uses lots
of this stuff for all kinds of projects, from simple to phenomenally
comples, with computer controls for all the moving parts. The current
project I'm working now on uses lots of it. We've come up with a few small
jigs to make drilling it easier, which is nice.
Here's a couple sites that came up with a quick web search, but there
are competitors that have some great stuff and is even cheaper. Each kind
has advantages. http://www.modularaluminum.com/ and
http://www.framingtech.com/
The Bosch stuff comes in like 20 foot pieces, and can easily be spliced
together with no loss in accuracy. I like it a lot.

John Smith wrote:
I am planning to build a very large CNC plasma cutting table for cutting
plates of 6000x2000 mm metric, so about 20' by 7'
Anyone know which company supplies rails and screws that long?


I would use a timing belt drive, Brecoflex sells the most precise belts.
As for the rails, thk style rails can be bolted on end to end. I have
designed long feeding mechanisms in this exact fashion and the resulting
machine was able to hold tolerances under 0.010" atlthough a lookup
table might have been used for error compensation.

stan

On Sun, 20 Feb 2005 21:02:09 -0600, stanley baer
wrote:

John Smith wrote:
I am planning to build a very large CNC plasma cutting table for cutting
plates of 6000x2000 mm metric, so about 20' by 7'
Anyone know which company supplies rails and screws that long?


I would use a timing belt drive, Brecoflex sells the most precise belts.
As for the rails, thk style rails can be bolted on end to end. I have
designed long feeding mechanisms in this exact fashion and the resulting
machine was able to hold tolerances under 0.010" atlthough a lookup
table might have been used for error compensation.

stan
Some cnc software has this option. You can use a laser or similar to
map the errors and tell the control where it really is.
ERS

why not consider using gear racks and spur gears? These and linear rails can
be joined.

"John Smith" wrote in message
...
I am planning to build a very large CNC plasma cutting table for cutting
plates of 6000x2000 mm metric, so about 20' by 7'
Anyone know which company supplies rails and screws that long?