Re: G02 Tolerance ?

[Phil Smith <phil-at-conwaycorp.net>]

Hugh & Denise Currin wrote:

> In the last few days I've gotten a foreign knee mill running under CNC, at
> least X & Y.  It's using ball screws, 750 oz-in steppers with 2:1 timing
> belts, Camtronic 5A drivers, opto-isolation from a computer running Red Hat
> 6.2, rtlinux & EMC.  Now that it is functioning I'll have a bushel of
> questions, I hope you guys have some patience.  Thanks. :-)
>
> First, I have a question regarding the g-code G02 command.  The first thing
> I'm doing is machining belt guards for the timing belts.  In checking my
> code I get the error that the radius from the start point is different than
> the radius to the end point.  I thought this was my hand coding and
> rounding to .001 but I just created code using Yeager ACE and can't see any
> problem in the code.  The code that give the error is:
>
> G01 X0.047366 Y2.186987 f40
> G01 Z0.000000
> G01 X0.102140 Y2.880401 Z0.000000
> G01 X10.662027 Y2.046252 Z0.000000
> G01 X10.607085 Y1.350706 Z0.000000
> G02 X10.607085 Y-1.350706 I10.375000 J0.000000
>
> I think the only relevant commands are the last two.  Why does this create
> an error?  Is there a tolerance setting in EMC for this?  I could not see
> one in the '*.ini' file.
>
> The error occurred while running "sim.run" in what I think is the standard
> distrubution.  (Thus explaining the feed rate of 40, visual output via
> backplot no cutting.)
>
> I can work around this using radius R rather than center I&J but would like
> to know how to adjust this tolerance.
>
> Thank you.
>
> Hugh
>
> --------------------------------
>   Hugh & Denise Currin
>     currin-at-cdsnet.net
>     Klamath Falls, Oregon  USA
>     541/884-3023
> --------------------------------

I havent programed any code for EMC yet as far as G code goes (read as
anything) other then playing with jog mode, but I can imagine that its also
important to have a G1 or other modal call after the arc command.
your code snipit stops after your arc.

G01 X0.047366 Y2.186987 f40
G01 Z0.000000
G01 X0.102140 Y2.880401 Z0.000000
G01 X10.662027 Y2.046252 Z0.000000
G01 X10.607085 Y1.350706 Z0.000000
G02 X10.607085 Y-1.350706 I10.375000 J0.000000

G01 X11.0 Y-2. F40     (MAYBE)


phil