CAD CAM EDM DRO - Yahoo Group Archive

Re: [CAD_CAM_EDM_DRO] Grizzly 2 axis rotary table

Posted by Jon Elson
on 2000-08-07 13:41:22 UTC
Doug Fortune wrote:

>
> In the summer 2000 flier by Grizzly, page 61,
> they have a 190 lb $895 10" tiltable rotary table
> (both axis on a 90:1 gear ratio) ie base 0-90 degress
> and table 360 degrees.
>
> Does any have one of these and know how good
> (or bad) the backlash is? The purpose of course
> is to mount motors on the handles and do some
> 5 axis turbine blade cutting (of course I don't know
> where to get affordable software for that, but
> first things first).

I have an antique indexing head, looks like it may have
been made in the teens or twenties! but, it is a very precise
unit, and had a clever adjustment mechanism for the engagement
of the worm with the worm-wheel. I tightened this adjustment
up until I got a hint of binding at one spot, and there is no
detectable backlash at the chuck. You might be able to
do the same sort of adjustment on the Grizzly unit.

As for the turbine blade profile, if you have some software
that handles the fluid dynamics performance of the blades,
then you get a grid of points. You can fairly easily write simple
programs to convert the grid and interpolate strings of points
along the surface, and then convert that to G-code, with the
appropriate offsets for the shape of the cutting tool. I don't
think that is such a hard problem. There is some trickiness
in finding appropriate angles to approach between the blades
to avoid a gouge, but a 3-D viewing program could let you
try a particular setup, and then you could see if a gouge would
occur.

More complex is the task of designing the proper blade profile
and determining the performance of it in the fluid dynamic
environment of the engine.

Jon

Discussion Thread

Jon Elson 2000-08-07 13:41:22 UTC Re: [CAD_CAM_EDM_DRO] Grizzly 2 axis rotary table