RE: [CAD_CAM_EDM_DRO] Re: CNC Pulse jitter?

Tim,

I agree that the problem does exist even though I don't see it as much with
my setup as you would on a higher performance machine. I really believe
that a major part of the reason I can not get reliable performance at higher
speeds is due in part to the jitters. For example, rapids run fine at 20
IPM for some period of time. I shutdown EMC and come back later, now when I
start the machine the rapids fail at 20 IPM but will work at lower speeds.
It has to be the jitters in the pulse train causing this since nothing else
has changed. I suppose the real answer to most of this problem in an
external hardware based pulse generator and a new module for EMC that can
handle the external pulse generation, like what Jon Elson is working on. I
wonder if the Gecko G210 with the step multiplier / regeneration capability
can help this problem any? Maybe a simpler solution to the problem is a
pulse regenerator that takes the incoming pulse stream, not caring about how
smooth or regular it is and produces a nice smooth output stream.

John Guenther
So much to learn, so little time
Sterling, Virginia

> -----Original Message-----
> From: Tim Goldstein [mailto:timg@...]
> Sent: Wednesday, April 17, 2002 9:21 AM
> To: CAD_CAM_EDM_DRO@yahoogroups.com
> Subject: Re: [CAD_CAM_EDM_DRO] Re: CNC Pulse jitter?
>
>
> John,
>
> It is not just the motors, but also the pulse instability. If you used the
> exact same setup (power supply, driver, motor, machine) and could
> send it a
> perfect pulse train you would find that the maximum reliable rate
> increases.
> Yes, you will get a faster rate by going to lower inductance motors with a
> higher voltage. But, that is just making the system more capable
> of handling
> the jitters. In our hobby class machines it is a very low cost
> way to solve
> the problem, but it does not mean that there is not a problem.
>
> Tim
> [Denver, CO]
>
> -----Original Message-----
>
>
> >Tim,
> >
> >I have tried to increase the speed and I can sometimes get it to
> run up to
> >about 20IPM but not reliably. These motors just won't run it
> that fast. I
> >will be changing the motors soon to some stronger units that have better
> >volt / amp ratings and higher torque.
> >
> >John
> >
>
>
>
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