Re: Cam program and post needed for a cnc propeller carving lathe

To Danny and Andrew,
Wood works out pretty good for airplane and wind turbine blades,It
doesnt develope cracks after repeated flexing unlike aluminium or
steel. Also it's cheap, light weight and easily worked. The famous
wind turbine builder Jacobs made variable pitch spruce blades about
30 ft, in diameter for his biggest wind plants and millions of units
about 14 ft. in diameter from the 1930's through the 50's. One left
in anartica performed unatended for many years.
Wide cicular saw type cutters were used by Blanchard who invented
the the pattern following gunstock producing lathe in the 1800's.
I proposed mechanically slaving the z axis to the spindel to avoid
a third servo controller. The program would be a very long series of
short interpolated G1 2 axis moves.
The lathe spindel would revolve at 20 RPM, rather slow.
One of the biggest forums for home built wind turbines is
www.fieldlines.com Just need the right cam program to make it happen.
Thanks, Larry Reiss Omaha, Nebraska

--- In CAD_CAM_EDM_DRO@yahoogroups.com, Andrew Werby <andrew@...>
wrote:

>
> 2a. Cam program and post needed for a cnc propellor carving lathe
> Posted by: "Larry" reiss_machinist@... reiss_machinist
> Date: Thu Jan 29, 2009 10:27 am ((PST))
>
> I am interested in building a cnc propellor carving lathe to

create

> wooden wind turbine blades, one blade at a time. The proposed lathe
> would be run with Mach 3 and 2 axis control having a servo motor
> drive on the headstock spindel and one on the cross slide axis.

There

> would be gearing and a lead screw to slave the Z axis from the

spindel

> at the rate of .125" per revolution.The cutting tool would be a 10"
> dia. carbide table saw blade that would move in and out on the

cross

> slide X axis as the spindel rotated continuously.
> I have use of a program that will create an STL. file of the
> blade.But I need to learn of a cam program that will let me define

the

> axis of rotation and has a post processor for a machine of this
> configuration.
> Thank You, Larry Reiss Omaha, Nebraska
>
> Hi Larry;
>
> [Is there a reason these have to be made in wood? Is this a

replication project, or are they supposed to be functional? If
you're creating these for a museum or something I suppose
authenticity counts, but for functionality I'd think you'd want
these to be made in a high-tech composite material that isn't going
to self-destruct in a high wind. No problem with mastering them in
wood, I suppose, but I wouldn't want to be anywhere near your home-
made wooden turbine when the prairie winds really pick up...

>
> That said, this is a pretty unusual machine you describe above.

Saw blades aren't generally used this way - I'd think you'd want
something more like a router bit to do the cutting. A lathe spins a
lot faster than you'd want it to for this; a rotary table would be
more to the point. And there's no need for gearing and lead-screw
slaving in the modern CNC era; the computer-controlled stepper or
servo motors do all that for you in a more controllable and flexible
manner. I'm pretty sure you won't find any posts for a machine like
this, but compared to building this beast, writing a post-processor
for it should be a piece of cake...]

>
> Andrew Werby
> www.computersculpture.com
>