A question of Scale.....
26 Feb 2019 09:39 #127147
by rodw
I did have a Gexko G251x and I did not think it was anything special against the Chinese ones I use now. Don't forget the steps we send to the controller is not necessarily the steps the controller sends to the motor. Current stepper controllers do step morphing and I have seen no performance penalties on my system. Quite happy with the 21 m/min I get out of my steppers.
Replied by rodw on topic A question of Scale.....
That high Microstepping kills all your Performence but ads allot of Issues to your machine
10 Microsteps as Fixed on the G540 Whow
I did have a Gexko G251x and I did not think it was anything special against the Chinese ones I use now. Don't forget the steps we send to the controller is not necessarily the steps the controller sends to the motor. Current stepper controllers do step morphing and I have seen no performance penalties on my system. Quite happy with the 21 m/min I get out of my steppers.
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09 Mar 2019 09:31 - 09 Mar 2019 09:36 #128146
by Richard J Kinch
On ordinary machine tools and shop measurements, yes.
Five microns is doubled by Nyquist, and doubled again by radial-operation/diametric-result operations. So you're already at a granularity of 20 microns = 0.0005in in your digital representation of desired outcome. That's a larger number than the minimum finishing cut an ordinary machine tool can make (typically a few tenths 0.001in), so it is not excessively precise for the genuine material limits of machining precision.
A lathe machinist working manually with a 5-micron DRO can repeat 5 micron tool positions and repeatedly hit diameters to 20 microns (0.0005in). Surely CNC should be able to mimic and automate that, or you're surrendering the best precision the machine can physically perform.
If 5 microns didn't matter, then why do we need micrometers that read 0.0001in and gage blocks with micron precision?
Replied by Richard J Kinch on topic A question of Scale.....
A red blood cell is about 5 microns wide. So then you need to ask yourself would a smear of blood only one cell thick affect your engineering outcome?
On ordinary machine tools and shop measurements, yes.
Five microns is doubled by Nyquist, and doubled again by radial-operation/diametric-result operations. So you're already at a granularity of 20 microns = 0.0005in in your digital representation of desired outcome. That's a larger number than the minimum finishing cut an ordinary machine tool can make (typically a few tenths 0.001in), so it is not excessively precise for the genuine material limits of machining precision.
A lathe machinist working manually with a 5-micron DRO can repeat 5 micron tool positions and repeatedly hit diameters to 20 microns (0.0005in). Surely CNC should be able to mimic and automate that, or you're surrendering the best precision the machine can physically perform.
If 5 microns didn't matter, then why do we need micrometers that read 0.0001in and gage blocks with micron precision?
Last edit: 09 Mar 2019 09:36 by Richard J Kinch.
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