RE: [CAD_CAM_EDM_DRO] How does a polygon turnign lathe work?

Look for the Technical Information pages at the bottom of this pdf:
http://tinyurl.com/6l3nwbn
It doesn't explain why it works, but it does an excellent job of explaining how to do it, and what results to expect.

It is interesting to note that, at least with an even number of faces, the flats are actually slightly convex, not concave.

Lou


-----Original Message-----
From: CAD_CAM_EDM_DRO@yahoogroups.com [mailto:CAD_CAM_EDM_DRO@yahoogroups.com] On Behalf Of Douglas Vogt
Sent: Friday, October 07, 2011 11:40 AM
To: CAD_CAM_EDM_DRO@yahoogroups.com
Subject: Re: [CAD_CAM_EDM_DRO] How does a polygon turnign lathe work?

My last post was premature. The animation seems to show that the flats are true flats, not concave because the work is turning at precisely the speed so that all of the embryo flat is the same distance away from the cutter from beginning of the flat to end. Interesting.


From: Henrik Olsson <henrik@...>
To: CAD_CAM_EDM_DRO@yahoogroups.com
Sent: Friday, October 7, 2011 1:38 PM
Subject: Re: [CAD_CAM_EDM_DRO] How does a polygon turnign lathe work?


 
Hi,

I'm no expert on this but AFAIK the only "magic" going on is the sync
between the main and sub spindle. The number of cutters and the ratio
between the spindles determines if you get a square, hex, etc.

Here's short animation showing how it works:

<http://video.google.com/videoplay?docid=-7831550688320827327>
http://video.google.com/videoplay?docid=-7831550688320827327#

And here's another video, not showing HOW it works but THAT it works. It's a
cool process.

http://www.youtube.com/watch?v=oGq-9NNmr3o

/Henrik.

_____

Från: CAD_CAM_EDM_DRO@yahoogroups.com
[mailto:CAD_CAM_EDM_DRO@yahoogroups.com] För wolfgang
Skickat: den 7 oktober 2011 19:03
Till: CAD_CAM_EDM_DRO@yahoogroups.com
Ämne: Re: [CAD_CAM_EDM_DRO] How does a polygon turnign lathe work?

it looks like a single point cutter that's moved in and out depending
on the angle of rotation of the cutting head.

The cutting head spin is synced to the lathe rotation by the shaft in
the back, so the two are moving in lock step. I'm guessing it's not a
1:1 gear ratio, otherwise the cutter would hit the same spot every
time.

On Fri, Oct 7, 2011 at 12:23 PM, Douglas Vogt <dbvogt@...
<mailto:dbvogt%40yahoo.com> > wrote:

> The flats may be concave after all but not noticeable at this diameter.

Look at the second video from citizen showing slow motion. The cutter makes
a much larger diameter pass on a relatively small diameter piece. The larger
the diameter cutter and smaller diameter work piece, the less concave will
be the flats of the hex. What is surprising is that the cutter diameter is
under CNC control as well as in the video you cite - the cutter makes a
second larger hex closer to the chuck without missing a beat. It seems the
number of "axes" in a machine can be extended well beyond what we're used
to. All possible due to CNC.

>
> Stop the video several times and you'll likely see a perfectly consistent

reflection on the flats as if they were truly flat. Stop it at 1.02 and you
see the top and bottom parts of the flat shiny but the middle of the flat is
darker suggesting concavity.

>
> Of course, this completely a guess :-)
>
>
>
> From: danmauch <dmauch@... <mailto:dmauch%40seanet.com> >
> To: CAD_CAM_EDM_DRO@yahoogroups.com

<mailto:CAD_CAM_EDM_DRO%40yahoogroups.com>

> Sent: Friday, October 7, 2011 11:44 AM
> Subject: [CAD_CAM_EDM_DRO] How does a polygon turnign lathe work?
>
>
>
> I saw thisamzing video http://www.youtube.com/watch?v=KMdBIBzGtKI and

can't quite figure out how the machine is cutting the hex so perfectly. I do
see that the cutter is just a staight bit and see that the millhead is
syncronized via drive shaft to the spindle. But with the cutter on the
perimeter of the milling head I would think the hex flats would be concaved.
So how does the machine actually work?

> Dan
>
>
>
>
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