[chbot] building CNC router - was Free stepper motors

[Mark Atherton]

Robin,

Any interest in standing up and doing a 10 min talk on the subj. next meeting ?

..also bring along a commercial controller.

Cover PC and OS requirements, interface types, software packages.

What would you do differently next time ?

Etc.

Sounds like you could save some members a lot of hair-pulling.

Regards,

Mark



At 02:23 p.m. 1/07/2011, you wrote:
>Hi,
>I've built a semi-successful CNC router/mill.
>I haven't used it to do PBCs but have routered up to 6mm Ali
>
>To do PCBs the best approach seems to be using a floating engraving head.
>This follows any contours in the board and so gives consistent cut width.
>Otherwise it's necessary to keep the board very flat during routing.
>
>The biggest issue has been with using a dermal as the spindle & lack 
>of rigidity. I've made my own spindle but have blown it up twice now 
>& so it's on the "to do" shelf for a while.
>
>Good drive electronics are important. I started with discreet chips 
>& dropping resistors but have moved to a commercial 5 axis board 
>that uses PWM current limit & micro step. The complete board was 
>cheaper that the list price for 5 of the chips. The boards are 
>listed on trademe but I go mine direct from China for about 2/3 the 
>price all up.
>
>Caution some types of unipolar steppers don't like being driven as 
>bipolar & others don't like PWM current limit.
>
>
>I'm happy to answer any questions & tell you what didn't work for me.
>
>
>Regards,
>Robin
>
>
>
>
>
>-----Original Message-----
>From: chchrobotics-bounces at lists.linuxnut.co.nz 
>[mailto:chchrobotics-bounces at lists.linuxnut.co.nz] On Behalf Of Cass Jones
>Sent: Friday, 1 July 2011 9:53 a.m.
>To: Christchurch Robotics
>Subject: Re: [chbot] Free stepper motors
>
>Thanks, having a look through now, any chance of earmarking  a set or
>should I just get there early? has anyone here made a pcb mill or done
>any cnc stuff before?
>
>On Friday, July 1, 2011, Chris Hellyar <chris at trash.co.nz> wrote:
> > Hi,
> >
> > They're all 200 step nema 17's.
> >
> >  From memory there were no matched sets of 3, but Richard can confirm.
> >
> > There would be some pairs for X&Y though.
> >
> > If you're keen on making anything cnc-ish check out the forums on
> > www.cnczone.com it's an awesome resource.
> >
> > Cheers, Me.
> >
> > On 30/06/11 22:23, Cass Jones wrote:
> >> Is there a set of 3 or 3 similar 200 step motors in there by any
> >> chance? I'm planning on making a circuit board mill as my next
> >> project.
> >>
> >> On Thu, Jun 30, 2011 at 9:42 PM, Richard Jones<rjtp at ihug.co.nz>  wrote:
> >>> In reply to Mark Becket I have appended photos of the stepper 
> motors to our
> >>> last meeting pics located here:
> >>> ChchRobotics2011June20 | 113134050398543502524 
> <https://picasaweb.google.com/113134050398543502524/ChchRobotics2011June20?authkey=Gv1sRgCLH0yquZjd6hVA&feat=directlink>
> >>> The motors were kindly donated by Chris Hellyar when he was tidying up
> >>> around last February.
> >>> I also have a few NiMH AA cells if people want those for 
> robots. I'll bring
> >>> these items to our next meeting on Monday 20th July 2011.
> >>>
> >>> Richard
> >>>
> >>
>
>_______________________________________________
>Chchrobotics mailing list Chchrobotics at lists.linuxnut.co.nz
>http://lists.ourshack.com/mailman/listinfo/chchrobotics
>Mail Archives: http://lists.ourshack.com/pipermail/chchrobotics/
>Web site: http://kiwibots.org
>Meeting Time and Location uncertain while Science Alive is out of action.
>
>When replying, please edit your Subject line to reflect new content.