Re: [CAD_CAM_EDM_DRO] servo or stepper size selection

Which ones do you recommend Bill, Dan for a Bridgeport Vertical Mill?

Vince

----- Original Message -----
From: "Dan Mauch" <dmauch@...>
To: <CAD_CAM_EDM_DRO@yahoogroups.com>
Sent: Sunday, January 05, 2003 7:19 AM
Subject: RE: [CAD_CAM_EDM_DRO] servo or stepper size selection


> I agree that a servo system using Gecko G320's and my servo motors is
> just about the same cost as an equivalent stepper motor system. I also
> love the silky smooth performace of the servo system. A servo system is
> a bit more tricky to set up because first you have to set the Gecko
> current limit, gain and dampening, then you have to dink with the
> software max speed, and acceleration but once you got it then you're
> set. I have converted most of my machines servo's and the last one will
> get them soon.
> Dan
>
> -----Original Message-----
> From: William Scalione [mailto:wscalione@...]
> Sent: Saturday, January 04, 2003 6:05 PM
> To: CAD_CAM_EDM_DRO@yahoogroups.com
> Subject: Re: [CAD_CAM_EDM_DRO] servo or stepper size selection
>
>
> Jan,
>
> I have to disagree with you here, I keep reading on this list how much
> cheaper stepper systems are than servo systems, and how much easier they
> are to set up, but I don't think that is necessarily true. Sure, if you
> are going to go with a full analog system the servo system will be more,
> but if you are going to use Gecko's or other step and direction type
> drives. the price is about the same.
>
> Drives - the gecko servo and stepper drives are about the same price,
> maybe a few dollars difference
>
> Motors - Just one example - Dan Mauch sells a 600 peak oz/in servo motor
> with encoder for $159.00, and a 785 oz/in stepper for $170.00. At
> anything more than a few hundred rpm's, that servo will have more torque
> than that stepper. On ebay or other surplus sources servo motors are
> usually much less than steppers
>
> As far as complexity, a step and direction servo system requires about
> the same amount of wires to hook the drive to the motor and computer.
> About the only thing more complex is using good shielded cable for the
> encoder wires, but you should be doing the same thing for the step and
> direction wires on both the stepper system and servo system, so it's
> nothing new.
>
> Performance - I have used both and I would never go back to a stepper
> system. No mid band instability or whatever it's called, just very
> smooth motion all the way from a standstill to top rpm. No missed steps,
> and most important, if the servo amp has not faulted, you can be 100%
> sure that the axis is where it is supposed to be. On a stepper system,
> there is always a doubt, that the motor has missed steps on that last
> circular interpolation that you had the override set too high on.
>
> I keep reading to buy the best you can afford when building your
> machine, then in the next sentence, someone will suggest going with
> steppers instead of servos. I guess I should be happy, as the $50.00
> servo motors on ebay have less bidders.
>
> What is the opinion of those on the list who have switched from steppers
> to servos, as to price and performance comparasion.
>
> Bill
>
>
>
>
>
>
> Addresses:
> FAQ: http://www.ktmarketing.com/faq.html
> FILES: http://groups.yahoo.com/group/CAD_CAM_EDM_DRO/files/
> Post Messages: CAD_CAM_EDM_DRO@yahoogroups.com
>
> Subscribe: CAD_CAM_EDM_DRO-subscribe@yahoogroups.com
> Unsubscribe: CAD_CAM_EDM_DRO-unsubscribe@yahoogroups.com
> List owner: CAD_CAM_EDM_DRO-owner@yahoogroups.com, wanliker@...
> Moderator: jmelson@... timg@... [Moderator]
> URL to this group: http://groups.yahoo.com/group/CAD_CAM_EDM_DRO
>
> OFF Topic POSTS: General Machining
> If you wish to post on unlimited OT subjects goto:
aol://5863:126/rec.crafts.metalworking or go thru Google.com to reach it if
you have trouble.
> http://www.metalworking.com/news_servers.html
>
> http://groups.yahoo.com/group/jobshophomeshop I consider this to be a
sister site to the CCED group, as many of the same members are there, for OT
subjects, that are not allowed on the CCED list.
>
> NOTICE: ALL POSTINGS TO THIS GROUP BECOME PUBLIC DOMAIN BY POSTING THEM.
DON'T POST IF YOU CAN NOT ACCEPT THIS.....NO EXCEPTIONS........
> bill
> List Mom
> List Owner
>
>
>
> Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
>
>
>
>