toolpath generation algorithm for NURBS

[jbacon]

Hi there,

I'm looking for an implementation of a toolpath algorithm
to mill 3d convex nurbs- or even polygonal surfaces on
a 3-axis milling machine. preferably it has a way of
specifying the tool contour from spline or polygonal
data as well. The output should be a set of contours
for each tool as hpgl or gcode.

Does anyone have a tip on where to find such
software ?

thanks in advance,

Jonathan

[bobJandal]

Pardon me,

Are you looking for actual programming code algorithms, or simply a cam package that does what you're asking ?

I have some crude algorithms in Java for doing parallel lace on a triangle mesh, but thats about all.

Certainly keen to compare notes and learn faster ways to do things, since my methods are bit brutish !

Cheers.

[jbacon]

Hi There,

I am looking for actual code, which is a bit smarter than
just scanlining a heightmap and takes into account that
it is quicker and nicer to go around a circular or cylindrical
area in a (NURBS) patch in circular motions. It'd also be
nice if it takes into account possible concave shapes when
using a convex tool. But it seems there is very little public
domain software for this. I am about to write it myself using
a brute force voxelspace-conversion and then 'stamping out'
the tool covering only voxels that are to be removed. this way,
you dont _have_ to follow a scanline- or any grid-like pattern.

any thoughts on this ?

J

[Tony the Ferret]

Hi Jbacon
not sure if i fully understand your requirement or needs, You did not give any idea of the application or type of part you want to machine, or the machine & Control.
When we looked into nerbs progranning back in the 1990's it was because the controls of the time were not fast enough to process the line data, and as a way of overcoming this the M/C tool guys proposed programing in Nerbs splines. But as time and controlers have moved on, this option is spoken about less and less.
I have a Post processor that will output a Nerbs spline for machining with. contact me and we can discuss it.