Re: [CAD_CAM_EDM_DRO]A question of size managenent.

Pardon me for jumping in, I am a newbie.

What enables a machine control to accept NURBS input? What machine
controllers can accept NURBS input?

Thanks
Joe Fahy

----- Original Message -----
From: "Marcus & Eva" <implmex@...>
To: <CAD_CAM_EDM_DRO@egroups.com>
Sent: Wednesday, November 29, 2000 12:24 PM
Subject: Re: [CAD_CAM_EDM_DRO]A question of size managenent.


>
> Hi Bill:
> How did the program get to having the arcs broken up into line
segments
> in the first place?
> Was the toolpath generated from a spline or a surface in the CAM software?
> Splines and arcs will output as line segments in most CAM software, since
> there are very few machine controls out there that can handle NURBS input.
> (Splines and surfaces are often described mathematically as NURBS
entities).
> Sometimes, it's difficult to determine if the entity you see on the screen
> is an arc or a spline.
> Most programs have some king of "analyze" function that will tell you.
>
> Anyway, back to your original question.
> A lot of the guys I worked with, preferred to take a simple 2D profile and
> program only the first pass.
> They would then "loop" the program to create all the subsequent passes.
> That gave them only one short chunk of code to edit.
> If you have multiple copies of your profile to cut, it makes for a very
> economical program, but you have to know how to set up the loop commands
in
> your particular controller.
> Hope this helps
>
> Marcus
> -----Original Message-----
> From: BillDarby <ddarby@...>
> To: CAD_CAM_EDM_DRO@egroups.com <CAD_CAM_EDM_DRO@egroups.com>
> Date: Wednesday, November 29, 2000 7:38 AM
> Subject: Re: [CAD_CAM_EDM_DRO]A question of size managenent.
>
>
> >Hi All
> >
> > I recently ran a tool path with 36,000 lines of code. (no big
deal
> in the real world) Now my question is this: This
> >path was really only 200 sets of (a line an arc and a second line) or
> [line, arc, line, 200 times]. "If" I could have entered the
> >summation of the 160 lines of code representing each arc into one common
> "arc command" I would have had a total of just 600 lines
> >of code.
> >
> > As it was, there was not enough memory to edit on the CNC. It
> could run the program, but if I wanted to change anything I
> >had to do the change on my off line program on my PC, then reload by
floppy
> to the CNC.
> >
> > Is there any software that could convert all these line commands
> into arc commands?
> >
> >Just compelled to ask!!!
> >
> >Bill Darby
> >
> >Also (have never seen my CNC do this before) As these [160 line] arcs
> became smaller my CNC began what appeared like a series of
> >jerky motions as it rounded these corners and sped up when it hit the
> straight-away. The cut looked and felt perfect but there
> >definitely some jerking going on as the entire mill set up a rocking
motion
> on the wooden floor. I almost thought the CPU was
> >bogged down. The feed was set at 32 IPM and dropped to less then 1/3 rd
on
> the corners.
> >
> >What do you think is going on??
> >
> >
> >
>
>
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