Author Topic: CV bad behaviour need improvement  (Read 14975 times)

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Offline skunkworks

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Re: CV bad behaviour need improvement
« Reply #30 on: April 11, 2012, 02:27:56 PM »
Don't forget to play with G64 Px.********* Qx.*********xx with linuxcnc.   It allows you to set path following tollerance to increase speed.

Make sure you are updated to the latest release of linuxcnc also (2.5 was just released)

There are a few threads similar to this where mach doesn't seem to obey machine accel/velocity constraints.  Linuxcnc doesn't have as large a 'look ahead' as mach but it does pretty well.


the reason for all headaches was to increase the feed, not to slow it down
my machine limits are 15m/min with acceleration time 0.2 sec
I guess that the problem on my PC become noticalbe a bit early bacause of different settings, more steps per unit, or something else, but soon or later that will become a problem when you wish to improve, it looks like the problem is with the motion algorithm when tryinh to calculate CV movements
unfortunately mach3 work smooth up to 3m/min, with increasing the feed is not so smooth anymore, in some situations do not decelerate, which is unacceptable, actually 3m/min is really good speed for all DIY, even too much for steppers
emc is a bit complicated to setup all features, but I used it for 4-5 days cutting and it looks like the movements are much better, same G code with the only change - feedrate. it is moving smooth up to 15m/min on straight lines only slowing down to 6-7m/min on short-lines-arcs, but still moving so smooth, with the current tool and spindle I can cut with maximum feed of 8.5m/min, and now I can use the full potential, for now I will stick with emc on my mill
so the problem with the mill is solved and Im very happy now, same G code is executed in a quater time than before, and same quality as mach3 on 3m/min
today I tried to run a lathe with mach3 turn, currently I struggle with M6, is not changing the tools, probably I have to read a bit more

Offline nik

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Re: CV bad behaviour need improvement
« Reply #31 on: May 11, 2012, 02:57:11 PM »
emc2 work even without tolerances much faster and much smoother (G64 only)