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I have replaced the main board of my Anet A8 printer with a Raspberry Pi based one, running PyCNC.

After many issues I have finally got to a point where all the motors work as well as heating and sensors.

However I am unable to print due to the E motor seems to run too much. How can I figure out what values should go to the config of PyCNC? I use Cura, maybe a different slicer/gcode format needs to be chosen? Thanks!!

# Maximum velocity for each axis in millimeter per minute.
MAX_VELOCITY_MM_PER_MIN_X = 3000
MAX_VELOCITY_MM_PER_MIN_Y = 3000
MAX_VELOCITY_MM_PER_MIN_Z = 300
MAX_VELOCITY_MM_PER_MIN_E = 150
MIN_VELOCITY_MM_PER_MIN = 1

# Average velocity for endstop calibration procedure
CALIBRATION_VELOCITY_MM_PER_MIN = 300

# Stepper motors steps per millimeter for each axis.
STEPPER_PULSES_PER_MM_X = 50
STEPPER_PULSES_PER_MM_Y = 50
STEPPER_PULSES_PER_MM_Z = 50
STEPPER_PULSES_PER_MM_E = 15

# Mixed settings.
STEPPER_PULSE_LENGTH_US = 2
STEPPER_MAX_ACCELERATION_MM_PER_S2 = 3000  # for all axis, mm per sec^2
SPINDLE_MAX_RPM = 10000
EXTRUDER_MAX_TEMPERATURE = 250
BED_MAX_TEMPERATURE = 100
MIN_TEMPERATURE = 40
EXTRUDER_PID = {"P": 0.059161177519,
                "I": 0.00206217171374,
                "D": 0.206217171374}
BED_PID = {"P": 0.226740848076,
        "I": 0.00323956215053,
        "D": 0.323956215053}

Update: None of the motors work properly. When I try to print a gcode file the motors travel too much an too fast.

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  • $\begingroup$ I'm not familiar with PyCNC, but generally, first you need to define how much is "too much" and after that you would need to most probably update your STEPPER_PULSES_PER_MM_E with a value other than 15. $\endgroup$
    – 0scar
    Sep 20 '19 at 7:56
  • $\begingroup$ Thanks for your comment. This is where I got stuck. I don't know what should be the number for STEPPER_PULSES_PER_MM_E. Actually, turned out all the other motors have this issue. I have no idea how to get these numbers. $\endgroup$
    – haxpanel
    Sep 20 '19 at 9:27
  • $\begingroup$ Generally you calculate the value, but you can use this one and measure how much extrudes so you can adjust to a new value. You could look into "How do I calibrate the extruder of my printer?" for hints. $\endgroup$
    – 0scar
    Sep 20 '19 at 12:18
  • $\begingroup$ Great, thanks, i'll have a look! How to calculate the other values, for the X Y Z motors? This is a common printer, can't i just use the values from .. somewhere? :) $\endgroup$
    – haxpanel
    Sep 20 '19 at 12:54
  • $\begingroup$ Yes, e.g. here. For the steppers: #define DEFAULT_AXIS_STEPS_PER_UNIT { 100, 100, 400, 100 } for respectively X, Y, Z and E. You've got too few steps configured, so X and Y are twice the speed, Z four times, etc... If those values work, an answer can be composed for you. $\endgroup$
    – 0scar
    Sep 20 '19 at 16:52

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