Re: [CAD_CAM_EDM_DRO] I'm curious

I'm not sure where you get the idea that reduction = backlash. I
worked on diamond turning lathes for years, several models in fact and
they all had belts between the motor and leadscrew. Every one of them
was a servo driven system and the belts where there for resolution.
Gearbox / belt reduction free systems are certianly possible, especially
given the explosion in equipment and manufactures, but they are not
cheap systems by any measure. Plus the idea of directly driving a
telescope axis with a motor large enough to do so is a bit unsettling.

If you are up to speed with respect to issues related to micro stepping
then why all the complaints about Geckos? I'm really trying to
understand your desires. Do realize that if you go with a servo drive
and encoder feedback you would need an encoder with very high
resolution. That sort of hardware is hard to find and expensive.

Thanks
dave


yahoo@... wrote:

>
>Reduction is backlash. You're in the optic industry, sure you understand
>that consideration.
>I fully understand the issues with microstepping with reference to accuracy.
>I believe that's one of my barriers to cracking 8 arcseconds.
>
>Jack
>-----Original Message-----
>From: CAD_CAM_EDM_DRO@yahoogroups.com
>[mailto:CAD_CAM_EDM_DRO@yahoogroups.com] On Behalf Of David A. Frantz
>Sent: Thursday, July 21, 2005 12:32 AM
>To: CAD_CAM_EDM_DRO@yahoogroups.com
>Subject: Re: [CAD_CAM_EDM_DRO] I'm curious
>
>I was talking about dropping a >>>>SERVO<<<< drive in place of a stepper
>drive.
>
>In any event you can not expect a micro stepping drive of any type to be
>extremely accurate. It is the nature of the motor and controller.
>If you want maximum resolution with good repeatability you need to look
>as servos as opposed to steppers. Or select a reduction ratioo for the
>stepper that keeps things in spec.
>
>The thought processes here revolve around systems with high performance
>and low cost that can implement the desired control. In any event the
>is the ..._EDM_DRO group so you might want to consider the CNC and
>motion control groups. As to answer to question, the responses
>require a bit of digestion. You shouldn't be surprised though when
>people try to realign you thinking.
>
>Thanks
>Dave
>
>
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