Re: [CAD_CAM_EDM_DRO]A question of size managenent.

Hi Joe:
There are a few high end controllers that are supposed to be able to
output code that comes from NURBS entities.
I have never even seen one and I have no idea how they work.
I assume that there must be special Gcodes to define NURBS toolpaths.

Marcus
-----Original Message-----
From: Joe Fahy <72510.1173@...>
To: CAD_CAM_EDM_DRO@egroups.com <CAD_CAM_EDM_DRO@egroups.com>
Date: Thursday, November 30, 2000 8:13 AM
Subject: 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??
>> >
>> >
>> >
>>
>>
>> Welcome to CAD_CAM_EDM_DRO@...,an unmoderated list for the
>discussion of shop built systems, for CAD, CAM, EDM, and DRO.
>>
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>> bill,
>> List Manager
>>
>
>
>Welcome to CAD_CAM_EDM_DRO@...,an unmoderated list for the

discussion of shop built systems, for CAD, CAM, EDM, and DRO.

>
>Addresses:
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>List Manager