Re: Can You Machine NURBS?

NURBS stands for Non Uniform Rational B-Splines. It is a way of
discribing a complex curve by math equations. Simular to splines.

If you have ever milled complex flowing curves (not a true arc) and
tried to do it with precision you notice that the post files can get
very large. The reason for this is that most cnc controllers can only
interpret straight lines and arcs/circles.

The really neat free flowing curve that you drew in your cad/cam has
to be broken up into really small lines or arcs to approximate the
original curve. So besides the really large post file you still are
not going to be able to machine the exact shape you drew. But you can
get close.

NURBS interpreters (CAD/CAM) will allow you to draw those artistics
shapes and import the math equation directly into the machine
controller. It is then up to the controller to calculate the cutter
path. It only takes a handful of lines of NURBS G-Code to describe a
complex free flowing curve. There are two advantages to this, you are
able to machine the exact shape you drew, and the post files come out
of the CAD/ CAM with a 60-90% reduction in size.

If you have ever milled a curve consisting of lots of small segments
you know how taxing it can be on your machine. The surface finish
also suffers from these small jerky movements.

Hope that helps

Matthew

--- In CAD_CAM_EDM_DRO@yahoogroups.com, JanRwl@A... wrote:
> In a message dated 12/10/2002 9:11:32 AM Central Standard Time,
> mjf46@j... writes:
>
>
> > or a machine controller that will machine NURBS?
> >
>
> Is this an anatomical part? Could you describe what that is for us
dummies,
> please?
>
>
> [Non-text portions of this message have been removed]