Re: [CAD_CAM_EDM_DRO] Re: Gear milling

npalen@... wrote:

> --- In CAD_CAM_EDM_DRO@y..., machines@n... wrote:
> > --- In CAD_CAM_EDM_DRO@y..., smoke@t... wrote:
> > > Anyone know of a SIMPLE program (possibly a plug in?) for
> > generating
> > > drawings of gears so's I can generate some g code for milling
> them?
> > >
> > Smoke,
> > Unless these are big gears how are you going to get a tool into the
> > gear shape?
> > Most of the gear generating programs are for wire eroders. Milling
> > with small cutters won't give you a deep enough face width.
> > There is a program here:-
> > http://www.simtel.net/pub/pd/41862.shtml
> > This will even generate the G code for you, or save as a DXF file,
> > but beware they are large files as it's all small moves.
> >
> > John Stevenson
>
> A possible solution for making gears for low speed applications would
> be laminating with rivets, screws etc. several thin gears machined
> out of sheet metal. The X and Y milling coordinates would generate
> the profile of the teeth around the periphery. The thin sheet metal
> would allow use of a small enough endmill diameter for a given tooth
> pitch as well as the keyslot. Machinery's Handbook should give tooth
> profiles which can be
> circular arrayed in a CAD program and dxf'd out for G-coding.

The best solution for small pitch gears is to use a double-angle tool
and cut on the side of the tool, with the axis of the gear at right angles
to the machine's spindle axis. Then, you use an indexing head to
turn the gear blank the required amount. You could also mill or turn the
correct profile for a gear tooth cutter.

Jon