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General Mach Discussion / RepRap printer and G92 pauses
« on: July 21, 2011, 11:32:36 PM »
Hey all,
I built a reprap earlier this year and trying to get decent prints using the opensource hardware was becoming a real head ache. After a couple of months dealing with random G-code bugs, ie premature move finish causing the rest of the print to be out of index, I decided to give my copy of Mach3 a try. I put it off thinking it was going to be a pain to cross over. I could not have been more wrong. The hardware interface was a breeze and the configuration was a no brainer. Should have done this a long long time ago.
The only issue I am running into, albeit small but annoying, is that when it goes to offset the extruder DRO back to 0 (G92 A0) there is about a .5 to 1 second pause. Just before the extruder makes a move with no extrusion it retracts the filament a few mm to prevent oozing. Once it is in position to start a printing move it executes G92 A0 and then primes the A axis the same distance as the initial retraction. The problem is the hot extruder deforms the area underneath it a little bit and sometimes it will begin to ooze a little bit due to the delay as well.
I removed all the M codes from the program so it isn't those. Watching the g code window, it always pauses on the G92. Why is there such a delay and what can I do to mitigate it? I mean, it is coordinating three vectors worth of movement at a time with out issue, the zeroing of an axis should take no time at all.
Here's a video clip of it happening. ideally the printer head should never stop or pause while printing.
http://www.ustream.tv/recorded/16161532
The Mach3 host machine is a Dell Dimension, Celeron 2.66 Ghz with 512Mb RAM using the on board lpt port.
Thanks for the help!
I built a reprap earlier this year and trying to get decent prints using the opensource hardware was becoming a real head ache. After a couple of months dealing with random G-code bugs, ie premature move finish causing the rest of the print to be out of index, I decided to give my copy of Mach3 a try. I put it off thinking it was going to be a pain to cross over. I could not have been more wrong. The hardware interface was a breeze and the configuration was a no brainer. Should have done this a long long time ago.
The only issue I am running into, albeit small but annoying, is that when it goes to offset the extruder DRO back to 0 (G92 A0) there is about a .5 to 1 second pause. Just before the extruder makes a move with no extrusion it retracts the filament a few mm to prevent oozing. Once it is in position to start a printing move it executes G92 A0 and then primes the A axis the same distance as the initial retraction. The problem is the hot extruder deforms the area underneath it a little bit and sometimes it will begin to ooze a little bit due to the delay as well.
I removed all the M codes from the program so it isn't those. Watching the g code window, it always pauses on the G92. Why is there such a delay and what can I do to mitigate it? I mean, it is coordinating three vectors worth of movement at a time with out issue, the zeroing of an axis should take no time at all.
Here's a video clip of it happening. ideally the printer head should never stop or pause while printing.
http://www.ustream.tv/recorded/16161532
The Mach3 host machine is a Dell Dimension, Celeron 2.66 Ghz with 512Mb RAM using the on board lpt port.
Thanks for the help!