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Author Topic: CV bad behaviour need improvement  (Read 16041 times)

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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.

http://linuxcnc.org/docs/2.5/html/gcode/gcode.html#_g64_path_blending_a_id_sec_g64_path_blending_a

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.

sam


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

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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)