RE: [CAD_CAM_EDM_DRO] EMC, ISA and other Questions...

I had occasion to use my rotary table to cut 3 slots aligned with the
circumference of the part. These slots needed to start and end in a 90
degree arc and I needed to compensate for the 1/4 inch cutter diameter. So
I needed to move the rotary axis 90 degrees and move the y axis .250 so that
cut would stop in the proper place. I was able to make these cuts using
TurboCNC with out any problems.

EMC when configured for 80 steps per degree (400*72 / 360) moves the rotary
table at a speed such that the motion is not noticeable. I personally think
it is granularity problem in EMC such that the small number of steps per
unit, in this case 80 steps per degree causes the velocity calculations to
go wrong. If however I configure the rotary table such that one unit = 28800
steps and issue commands such as G01 A.25 to move 90 degrees all is fine,
the table moves at the desired speed. However I do not want to treat my
angular axis in this manor. I will try this with Mach1 to see what it does
with the rotary table on the A axis.

John Guenther
'Ye Olde Pen Maker'
Sterling, Virginia

> -----Original Message-----
> From: Jon Elson [mailto:elson@...]
> Sent: Wednesday, January 22, 2003 12:36 PM
> To: CAD_CAM_EDM_DRO@yahoogroups.com
> Subject: Re: [CAD_CAM_EDM_DRO] EMC, ISA and other Questions...
>
>
>
>
> Tim Goldstein wrote:
>
> >Jon,
> >
> >Maybe some of them should talk to Art at www.ArtofCNC.ca about how he
> >fixed it in Mach1. He has done a marvelous job in handling a rotary
> >axis. You input the distance Z = 0 is from the center of the rotary axis
> >and Mach1 then adjust the feeds to maintain the desired feedrate at the
> >tool tip.
> >
> >
> Ahh, indeed, this is what we need, too. But, if the other axes are
> moving in coordination with
> the rotary axis, then the radius could be changing throughout the move.
>
> Jon
>
>
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