Re: [CAD_CAM_EDM_DRO] Re: Ball screws for CNC plasma cutters

Perhaps a system using those "cable gears" from Berg would work well for a
20' machine..like Helen wants to build?
Should be a lot cheaper and easier to build than using a 20 foot long rack!
Wouldn't require a precision rack mounting surface either.

An even easier way would be to mount the unit using a plain cable. Fix both
ends of the cable to a shaft driven by the servo motor. At the other end
wrap the cable around a pulley. Use a cable on both sides of the machine to
equalize forces. Link the safts on opposite sides with a "cable belt".
Build the Y axis the same way. All you'd need is a track guide for the
mechanism holding the torch. You could run a system like this at just about
any speed you wanted to.

And for those of you who say a "cable drive" wouldn't work...I ask..."Have
you tried iit?" I do know of some equipment that uses cable drives very
effectively.

Smoke

>If you've seen a plasma cutter then you have also seen all the particulate

slag and grit that is generated. This grit can play havoc

>with any type of screw. A better solution is a rack and pinion drive. If

the teeth on the rack are positioned vertically or upside

>down the grit problem is minimized. Racks can also be of unlimited length.

Screws on the other hand suffer from whip lash at longer

>lengths. My 72 x 126 inch CNC plasma, with rack and pinion drive, holds the

same tolerances it did when it was new fifteen years

>ago.
>
>Jay Hayes
>