Re: [CAD_CAM_EDM_DRO]doodling with ideas

Bill,

Yes, there are a number of ways to do what you mention, squares, hex,
etc. The obvious way is with "live" tooling, that's like having a
milling spindle mounted in your lathe's tool holder and indexing the
spindle to mill the flats. Big buck CNC lathes use this method all
the time. Unsymmetrical shapes like cam lobes are done the same way,
except the lathe spindle is rotating slowly as the milling spindle
moves in and out to create the shape. These methods are fairly
slow, but have the advantage that a part can usually come off the
lathe complete without needing second operations on a mill.

Another way is by using a polygon turning attachment. This is fast.
Polygon attachments "turn" various symmetrical shapes on work while
the lathe spindle is turning at high speed. A polygon attachment
uses an auxilliary rotating spindle with a wing type cutter rotating
in synchronization with the lathe spindle. Polygon attachments are
mostly used on high production non-cnc lathes by using a gear train
to synchronize rotation the two spindles. Most CNC lathes don't have
an easy way to adapt a gear train, but I've been thinking it might be
a natural to electronically synchronize the spindles.

Another method of making both internal and external symmetrical
shapes on lathe parts is with a "wobble" broach. This is fast. With
a simple attachment you can easily make internal (or external) hexs
(and other shapes) while the lathe spindle is rotating at high
speed. The wobble broach was developed for high production non-cnc
machines, but can be used as well in cnc lathes or mills. I have a
couple of CNC lathe parts where we use this attachment. One part is
a small round head SS screw with a 1/8" hex socket in the head. The
1/8" hex is made in a few seconds while the part is running about
1800 rpm.


Doug

--- In CAD_CAM_EDM_DRO@egroups.com, BillDarby <ddarby@s...> wrote:
>
> Was just sitting here wondering if anyone has used any CNC lathe
software that would allow you to turn shapes, other then just
> circular. It occures to me that under CNC control, a lathe should
be easily capable of turning all sorts of shapes (squares, hex,
> lobs, cams)????
>
> Bill Darby