Re: [CAD_CAM_EDM_DRO] Rotary table DRO

Hi B

Yes it is possible to gear drive an encoder. You then have to deal
with the reality of backlash and other errors. It might be useful to
put the encoder on the shaft driving the worm, thats assuming of course
that you have a worm drive. finally you can go out and buy very high
resolution rotary endcoders but you aren't going to want to pay the
price.

As far as rotary encoders go the best I've seen, this was a few years
ago, was a system that delivered 500000 counts to the servo loop.
That was after some on board resolution multiplication, I'm not sure
anymore what the "real" resolution of the encoder was.

Once in the world of very high resolution devices you will experience
limitations that one does not often see with run of the mill systems.
One thing to be concerned with is the maxium speed that the encoder is
capable of tracking.

thanks
Dave


babinda01 wrote:

>Hello,
>
> I was wondering if someone may be able to help me with a problem I
>have at the moment.
>I am trying to add a DRO to my 'little' rotary table. It is 6 meter
>diameter. I am looking to get .05mm accuracy if at all possible. I
>was thinking of puting a rotary encoder onto the main spindle which
>is coupled directly to the table, but to get the resolution I am
>looking for I need approx 400 000 pulses per rev (0.00095 deg). All
>the encoders I have looked at seem to be about 8000 pulses per rev in
>quad. Is it possible to gear an encoder up? If so how (so as to get
>minimal backlash)?
>
>Thanks for your help
>Andrew
>
>
>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@..., timg@...
>Moderator: pentam@... indigo_red@... [Moderators]
>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/
>
>
>
>
>
>