Re: [CAD_CAM_EDM_DRO] Re: Step resolution question, dividing head

ballendo@... wrote:

>
> Jon,
>
> My first thought was the same as Peter. You sure it's only 4:1?

Yep, 4:1. It's really a nice setup, with the 90 hole plate it's direct
indexing in one degree increments.

1 degree motors are not very common, and especially in any size.
I'm working with what I have, which is the cheapest route of all.
I don't plan on trying to resolve moves to arc-second accuracy, but
what I wanted to achieve is full even microsteps for any full angle
move, within the limits of what I can fit to the unit. I might be able
to do a bit better going somewhere other than MSC for the pulleys.
I made up a spreadsheet to check all the microstep resolutions available
on my Compumotor OEM650, and 18,000 micro steps is the first resolution
available that gives me even steps/degree at any pulley combinations I
can make up from MSC's stock. Part of the problem is the motor has a 3/8
shaft, so right off I have to bore a 5/16 pulley just to get a decent
sized drive pulley.

Another reason for using the motor I have, is it was fitted with a brake
(was used for a very heavy vertical slide originally). With a 4:1 ratio,
it could be possible to back drive the indexer. Not likely, but since
the results of such an event would be a disaster, the brake is cheap
insurance. It'll be controlled by an M function eventually.

Main thing is to know I got my math right. I can now go play with
alternatives and see if I can come up with something better.

Thanks,

Jon