RE: [CAD_CAM_EDM_DRO] EMC vs. Mach2

Hi Jeff

EMC has constant velocity contouring. I regularly use it
with program paths that have hundreds or more segments per inch
at up to 200 ipm.

The planner is a simple trapezoidal velocity type so it could
be a bit smoother. It connects segment corners with a blended
parabola. This of course means the path misses the point because it
rounds the polygon. It also means that acceleration has sudden changes.
Running with low specified acceleration helps to keep
a smooth path.

There is a new version of emc that uses a third order planner
called segmentqueue that is very smooth. It uses pseudo waypoints
such that the path is a true spline...it passes through the actual
waypoints. Currently it does run but has some problems at high speeds.
It is being worked on.

Can't comment on Mach 2 as I only use servo based systems...

Les

Leslie M.Watts
L M Watts Furniture
Tiger Georgia

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-----Original Message-----
From: ja_erickson [mailto:ja_erickson@...]
Sent: Friday, July 30, 2004 5:55 PM
To: CAD_CAM_EDM_DRO@yahoogroups.com
Subject: [CAD_CAM_EDM_DRO] EMC vs. Mach2


greetings,

i am currently using a controller software called mach2 which is
windows based but it seems to have problems with lost steps and some
other issues. my questions are does anybody have experience using
emc and mach 2? if so what are your opinions of the two. mach 2 has
alot of capabilities for blending and constant velocity contouring
as well as an exact stop mode which is supposed to be more accurate
but produces tool marks on the part. there seems to be some issues
about the blending and rounding of toolpaths when using the constant
velocity modes in mach2 which makes me think that the resulting
finished geometry may not be correct in some conditions. what are
some of the toolpath characteristics of emc as far as its smoothness
and accuracy when machining short linear 3d moves like when your
machining a mold cavity? i really could use some guidance here
as far as selecting a software. anything else you could add would
be great !

thanks in advance
jeff