RE: [CAD_CAM_EDM_DRO] slave motor for geko 340???

There are many systems that use 2 motors on one axis. The trick is to
use a separate driver with each motor. In the case of steppers hooking
up the step and direction signals to both units will result in matched
movement assuming

A) matched motors.
B) no slipping ( motors must be rated, like in any app, to be strong
enough.

In the case of servos, matched motors with matched encoders will do the
job.


David


-----Original Message-----
From: alex [mailto:telecomt@...]
Sent: Monday, November 18, 2002 7:01 AM
To: CAD_CAM_EDM_DRO@yahoogroups.com
Subject: Re: [CAD_CAM_EDM_DRO] slave motor for geko 340???


Maybe to install sprockets on the shafts and connect them with the
chain? This should keep them in sync. Alex

----- Original Message -----
From: Jon Elson <elson@...>
To: <CAD_CAM_EDM_DRO@yahoogroups.com>
Sent: Sunday, November 17, 2002 10:41 PM
Subject: Re: [CAD_CAM_EDM_DRO] slave motor for geko 340???


>
>
> Brent Fuchs wrote:
>
> >I am building a gantry style machine to route wood with.
> >2 of the axises have 2 screws each, I have decided to use
> >a motor for each screw. Is my thinking correct? can I use two servo
> >motors per geko 340 by connection one as a slave with no encoder,
> >just connecting the armature???
> >
> >
> no, absolutely not. Slight variations in the motors, friction,
> weight, etc. will get them out of sync very quickly (like less than a
> second). You need to have a home switch on each portion of the axis.

> This is called a tandem axis in CNC
> parlance. It is frequently used on gantry-type machines like vertical
> boring mills
> and bed mills. You would need a separate Gecko servo drive and
encoder
> for each
> motor. The gantry or axis will need to be constructed with links and
> bearings so
> the axes will not bind when slightly out of sync. You will have to
add
> some logic
> between the CNC computer and the Gecko drives that stops the step
pulses
to
> whichever motor reaches the home position first (when in search for
> home mode). This should allow both axes to be moved to home. Then
> this bit of logic would
> be switched to normal mode, and let all step pulses through to both
> drives, and
> they should stay in sync as long as they both stay enabled.
>
> If you can't arrange the bearings and links to prevent binding when
> out of sync, then you will need to use one motor and belt drives to
> keep the two screws synced.
>
> Jon
>
>
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Addresses:
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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



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