Problems controlling Feedrate and motor speed.
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Hello,
Any assistance could be highly appreciated.
I have problems with accurately controlling the speed of the motors using DUET 3D.
Let me explain my case first: I am have a 3D bioprinter prototype. Instead of using ordinary printheads, I have self-made extrusion pumps. these pumps consists of a stepper motor that presses an ordinary syringe, which by its turn extrudes the material outside of it. What concerns me is that I have difficulty controlling the speed and the feedrate control of these motors. I have verified that the steps-per-millimetre is correctly calculated, and the theoretical and real displacement match. yet the motors are unable to execute the actions sometimes at the right speed. For example:
G1 U10 F5: executed in 20s. wrong
G1 U10 F10: executed in 20s. wrong
G1 U10 F20: executed in 20s. wrong
Above F50, correctly abiding by the feedrate rate. correct execution time.
Any thoughts on that?
Thanks in advance. -
I believe you may be running into the minimum feed rate limit.
F5 is 5mm/min
https://docs.duet3d.com/en/User_manual/Reference/Gcodes#m203-set-maximum-feedrate
Innn Minimum overall movement speed (firmware 2.03 and later), default 30mm/min
RepRapFirmware has a default minimum movement speed of 0.5mm/sec, or 30mm/minute.
Gcode commands sent with a slower feedrate than this (e.g. drilling) will automatically run at this speed.
In firmware 2.03 and later this can be changed using the I ('i') parameter of the M203 command. For example, for a 10mm/minute minimum speed, send:
M203 I10 ; set minimum speed to 10mm/min -
@Phaedrux, Thank you so much for your on-point remark ! Best, Selman.
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@Phaedrux, feedback: I put it to the test and it works ! thanks again !
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