Does CAM use NURBS to generate toolpath?
Does CAM use NURBS to generate toolpath?
(OP)
Hi,
I have a doubt regarding toolpath generation in CAM software in general. Modern CAD/CAM systems represent surface and solid data in NURBS form. But while generating tool path does CAM software use NURBS data directly or does it convert NURBS data to Triangulation format? I heard that some CAM software convert in this way. If they do, what is the necessity for such conversion?
Many thanks.
I have a doubt regarding toolpath generation in CAM software in general. Modern CAD/CAM systems represent surface and solid data in NURBS form. But while generating tool path does CAM software use NURBS data directly or does it convert NURBS data to Triangulation format? I heard that some CAM software convert in this way. If they do, what is the necessity for such conversion?
Many thanks.





RE: Does CAM use NURBS to generate toolpath?
NX8
RE: Does CAM use NURBS to generate toolpath?
John Joyce
N.C. Programming Supervisor
Barnes Aerospace, Windsor CT
NX6 & NX7.5
RE: Does CAM use NURBS to generate toolpath?
John R. Baker, P.E.
Product 'Evangelist'
Product Engineering Software
Siemens PLM Software Inc.
Industry Sector
Cypress, CA
Siemens PLM:
UG/NX Museum:
To an Engineer, the glass is twice as big as it needs to be.
RE: Does CAM use NURBS to generate toolpath?
NX8
RE: Does CAM use NURBS to generate toolpath?
Can you explain what is this conversion to triangulation?
Also will the parameters generated by NURBS toolpath same as those that are defined for NURBS surface in CAD? Or will it reconstruct a new NURBS surface? I mean if I know the NURBS parameters from CAD model, can I directly use them in altering the NC code (using appropriate G code)?
Thank you.
RE: Does CAM use NURBS to generate toolpath?
John Joyce
N.C. Programming Supervisor
Barnes Aerospace, Windsor CT
NX6 & NX7.5
RE: Does CAM use NURBS to generate toolpath?
The main reason is reliability, especially with complex topology or poor geometry with issues like gaps between edges, overlapping surfaces, etc. This does not affect the accuracy of the tool path.
In NX, we use both direct offsetting and faceting, depending on the geometry, operation, and tool axis.
Mark Rief
Product Manager
Siemens PLM
RE: Does CAM use NURBS to generate toolpath?
My original question is what markrief answered. Sorry for not being clear. However I got doubt on its usage on machine tool when joycejo posted his first reply. So I added that as well. I agree with what others said about requirement of machine tool. But I think more specifically it depends on control - as I've seen it on Siemens 840D few years back.
Now it's clear to me that to accommodate poor geometry CAM software does triangulation or tesselation. But why operation and tool axis influence the choice?
Thank you.
RE: Does CAM use NURBS to generate toolpath?
There has been a lot of research in this area, so maybe you will find the details you are looking for in a published paper somewhere.
Mark Rief
Product Manager
Siemens PLM
RE: Does CAM use NURBS to generate toolpath?
Regards,
Tomas
RE: Does CAM use NURBS to generate toolpath?