Re: [CAD_CAM_EDM_DRO] Subject: Re: AMAZING STUFF!

Backlash has to be handled some way or your machine will never return spot ever in its life. So if a closed system is no good
then what can be done. Sony makes a feed back hook up for closed systems.
Larry

Roland Friestad wrote:

> From: Roland Friestad <cardinal.eng@...>
>
> I try to read the messages pretty regularly but don't contribute a lot since
> there always seems to be someone out there who has the answers to questions
> that arise and so my own comments are usually superfluous -
>
> However the point about a system of using a DRO of some kind to "close the
> loop" on a stepper motor is something that to my knowledge has been around
> for at least 25 years - I've been using and working with NC and CNC for
> nearly 35 years and this concept has been used several times with various
> levels of success -
>
> The implementation of the electronics is pretty straightforward with the
> software being more complicated and overcoming the realities of the physics
> of machining with "backlash", "hysterisis", or "wind" in the system being
> the most difficult problem of all - It has been said, after all, that you
> "can't fool mother nature" -
>
> Electronics and computer software can be pretty wonderful stuff but
> machining using CNC with backlash can be a really frightening experience for
> those who are unaware of the amount of kinetic energy that can be stored in
> the resulting flying parts caused by mixing backlash and CNC - As someone
> who has had the misfortune to be in the way of such flying pieces and had to
> endure the resulting personal damage I would hate to see someone else have
> the same problem because I didn't speak up -
>
> On another topic - I'll issue another invitation to display or participate
> in the CNC seminar to be held in Wyandotte Michigan at the annual NAMES show
> - End of April - Contact me for more details off list if you are interested
> - Several folks have already signed on and it is always a pleasure to meet
> and greet people with common interests -
>
> Roland Friestad
> cardinal.eng@...
>
> Copy of message follows
> **********************************
> Message: 10 - Digest #399
> Date: Sat, 11 Mar 2000 18:17:27 -0000
> From: "james owens" <wotisname@...>
> Subject: Re: AMAZING STUFF!
>
> Some time ago I proposed a system using DRO input to a CNC program for
> stepper motor control of workshop machinery. The idea was considered to have
> "No Merit" and not of commercial value. I proposed it as a means of using
> lead-screws that have some wear and still achieving an accurate CNC
> machining centre. I have continued to develop my thoughts and am close to
> achieving the required results. It has taken so long because it was
> necessary for me to start from scratch without the benefit of readily
> available components.
>
> Is this a case of parallel development or piracy. Don't get me wrong if this
> is piracy Dan has every right to produce this application but it would be
> nice to have been given a little recognition.
> *********************************
>
> ------------------------------------------------------------------------
> GET A NEXTCARD VISA, in 30 seconds! Get rates
> as low as 0.0% Intro APR and no hidden fees.
> Apply NOW!
> http://click.egroups.com/1/975/1/_/423600/_/952890758/
> ------------------------------------------------------------------------
>
> Welcome to CAD_CAM_EDM_DRO@...,an unmoderated list for the discussion of shop built systems in the above catagories.
> To Unsubscribe, read archives, change to or from digest.
> Go to: http://www.onelist.com/isregistered.cgi
> Log on, and you will go to Member Center, and you can make changes there.
> For the FAQ, go to http://www.ktmarketing.com/faq.html
> bill,
> List Manager