Re: [CAD_CAM_EDM_DRO] best servo drives

With so many people using Geckos successfully, I can't believe they
aren't accurate - however they do have fussy step/direction timing
requirements and in my own experience, I've had a lot of trouble working
with Flashcut and Geckos and getting 100% step accuracy in large 3D
files. The problem is non-existant in simple 2.5D work. Flashcut is
working on providing additional configuration setting to better work
with Geckos, I suspect. Jon E recently suggested a flip-flop circuit
which may well solve the problem and I intend to test it a bit later in
the week. I will report my findings to all.

I've been impressed with the performance of the Rutex R990 20A servo
drives - they are very smooth with no cogging when stopped. The R990
does emit a 12kHz (PWM freq.) squeal which I find quite irritating - I
understand a model upgrade is due early this year, raising the PWM freq
to around 20kHz - this model would probably be worth waiting for. They
do require two power supplies (unlike the Geckos) however this is not
unreasonable and they run VERY cool. Only minimal heatsinking is
required. Set-up was quite straightforward but not as easy as the Gecko
G320 which allows you to exactly optimize the PD settings with a scope
by monitoring the error signal. I'm not sure where you saw the
"automatic tuning" - I certainly didn't see any reference to that for my
drives, maybe it is available on another model. I think that would be a
wonderful feature and the Rutex drives might be able to offer it as they
are PIC based (i.e. microprocessor) rather than the Geckos being
discrete logic - as far as I know.

I found the Rutex drives arrived from Australia with 4 days of me paying
for them via paypal, very impressive! Unfortunately, I've been a little
disappointed with Rutex's tech support - Vladimir at Rutex has been slow
to non-responsive to some of my email questions. I called him before
Xmas and he was very helpful - but I haven't received any replies this
year! Maybe he is still on holidays... (It is summer down-under)
Also, Australia isn't that far by phone - and most phone discount plans
only charge 10-15c per minute so don't let the distance put you off.

Cheers, Peter (an Aussie living in Canada - by choice!)



ironarbor2003 wrote:

>Ive recently been looking to upgrade frome stepper to servo motors on
>my plasma table, does any one know wich is the best?
>
>Gecko
>A guy from flash cut called me today and told me that geckos were not
>accurate and that they missed steps? Is this true or a sales man
>doing his duty to put down everyone else?
>
>
>Rutex
>Hows shipping, I see that they automatically tune themselves?
>
>Any other"lower cost" drives out there?
>
>
>
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