Re: CNC acetylene torch table drive

People,

After some feedback, I updated the design for the proposed acetylene
torch table.

Please view my updated design:

http://openfarmtech.org/index.php?title=Torch_Table

Please let me know if you see any issues or inaccuracies that I should
correct.

Sincerely,
Marcin


--- In CAD_CAM_EDM_DRO@yahoogroups.com, "marcin_ose" <marcin_ose@...>
wrote:

>
> Hello,
>
> I am looking at Xylotex.com 425 in oz motors to drive the long axis of
> a 4'x8' torch table. I'd like to use a 3/8" pitch by 1/2" wide belt
> that functions as a rack. The pinion is a pulley of 2" diameter. I'd
> like to have one drive motor on each side of the long axis.
>
> Would I be able to drive the pulley directly with the motor, or do I
> need some gearing on the motors? The carriage will be the is the
> lightest possible tube, just to carry an acetylene torch head.
>
> My concern is having adequate traction between the belt rack and the
> pulley. Is gravity sufficient to hold onto an upward-facing belt rack?
>
> I've considered ball screw assemblies, but it appears that I don't
> need such high accuracy, and simple belt drive will get me at least
> 1/30 inch accuracy on the torch table, and better if I use
> microstepping. Are the 3/8" pitch pulleys sufficiently accurate as I
> indicate with the calculated 1/30 inch? I am trying to do the
> rack-and-pinion belt instead of ball screws for lower cost. The
> original design was screws- but I'm moving onto rack and pinion, with
> 2 motors on the main axis to get the drive mechanism away from the
> working area.
>
> http://openfarmtech.org/index.php?title=Torch_Table
>
> Sincerely,
>
> Marcin
> http://openfarmtech.org/weblog/
> http://openfarmtech.org/index.php?title=Overview
>