Re: [CAD_CAM_EDM_DRO] Plasma table gear reduction

Hi Dave,

This is one of the problems with r&p or belt drive. The reduction ratio
you need is
(pi * gear diameter * motor rpm )/feed rate

For a reasonable sized plasma cutter (say 8' x 4') you want at least
200IPM rapids. Even my little stepper driven machine does more than that.

Let's assume your motor does 1000RPM and you have a 1" diameter gear.
For 300IPM the reduction would be:
(3.14 * 1 * 1000)/300 = 10.5:1

To get this sort of reduction you have no real choice but to go for two
stage reduction with a jack shaft of some description.

Les


turbulatordude wrote:

>Hi all,
>
>Next step is the transmission.
>
>Assuming a 1,000 RPM servo motor (for ease of calculations)
>
>and a rack or belt drive.
>
>It would appear that the lowest gear ratio is about 1:1 and that is
>using a pretty small drive gear.
>
>Assuming one wants 100 inch per min speeds, there is a need for a
>10:1 reduction.
>
>I can get a pair of timing belt pulleys for about a 3:1, maybe a 4:1,
>and that would indicate that a jackshaft would be in order for two
>sets of belt reduction.
>
>This seems pretty striaght forward and different pulleys offer the
>ability to change ratios.
>
>Obvously, when the surplus motors are spinning 4 times faster, it
>means the need for a reduction is required.
>
>Is there a simplier way to do reduction ?
>
>Dave
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