Re: cnc bar feed

Doug (comments mixed in)

   From: Doug Fortune <pentam@...>
<s>> like virtual bar feed with a long bar --

>> and run programs over night.  

These virtual parts are easy to ship. I'd attach a couple so you could
check tolerance but Bill won't allow attachments. <g>

>Neat.  How did you arrange the 'advancement' of the bar?
>I presume it was a single bar per setup, rather than a
>stack of bars which fed in sequentially.  

When I run the EMC overnight it's virtual cutting.

I do have a bar feed with the Hardinge made from a chunk of tubing.
Hardinge used a lot of these on their chuckers. Some of the fancy ones
use a two part bar pusher. the bar end is cupped and runs in a sealed
bearing. Behind it is a short rod with a bearing seal pressed on the back
and rubs against the inside of the tube. No rocket science here.

Low pressure air pushes on the bar and when the collet is opened, it bangs
the bar into a stop on the turret. Just move the stop close to the
cut-off position, open the collet, move z to the length you need and close
the collet.

>You must also have
>had some 'enclosure' for the part of the bar sticking out
>the left side of the headstock - to prevent it whipping.

The tubing does that. Max size with a 5c collet is about 1" so we aren't
dealing with big stuff here. I chamfer the bars a little so they fit in
the cup and at most speeds there is very little whip. If the stock is
real small < .200, I keep the bars short and usually the air pressure will
keep the whipping down.

> Did the finished part just fall off and remain where it lay,
> or was there a 'collection' mechanism for the finished parts too?

Hardinge makes an air powered sliding parts catcher that slips in under
the spindle nose while you do the cut. If you have coolant running from
above, it will wash the cut part down onto the bed of the lathe beside the
headstock.

HTH

Ray

Doug Fortune
http://www.cncKITS.com