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Noise between G1/G0-commands

Georg99Georg99
in Motor Control
I use Ramp1.4 with Repetier 0.92.9 for a x,y plotter.
The plotter ist hanging on a wall.
Speed is low 15mm/s and acceleration 10mm/s2.
I want that the plotter is slow and quiet.
The motor sound is good, but ..

There is a noise (like "tak"), if one G1 or G0 commands ends and the next one starts (SD-card).
There is no noise during the command itself.
The noise is not loud, but louder than the motors.

I do not remember this sound from my 3D-printer.
I changed speed, jerk and acceleration, but this does not influence the "tak" between the commands.

What can be the reason?
Does the motor stop shortly between the commands?
Thanks!



Comments

  • RepetierRepetier
    If commands come fast enough the moves get queued so there is no pause. But if you change direction between commands it will get slower and then faster if jerk is exceeded and that is something you can hear. Also on some printers especially if they have backlash you can hear direction changes.
  • Georg99Georg99
    Thanks for your comment!
    The direction changes about 15 degrees. My impression is that the tak is always to hear independent on the length or direction of the next way.

    Do you suggest a jerk more like 40?
    The buffer is always close to 16 - is that a sign for no backlash?
  • RepetierRepetier
    Buffer 16 means you have no pauses between move since the next 15 moves are also loaded a precomputed.
    Backlash is if your printer head has play so on direction changes it might need 0.1 move before it starts moving. Then belt has already bigger speed and you might here it starting.

    Higher jerk reduces slowdown but can lead to lost steps if you exceed the forces of motors and printer get more jerky and shake more. Since you speed is 15 jerk 30 means no acceleration/deceleration at all. It will always start at full speed (15).
  • Georg99Georg99
    I changed jerk to 2 - but no change with the noise.
    The noise is exactly the same, so it is not influenced by jerk.

    I tested it only with only one motor - the noise is still there, no matter what motor is off
    (with no motor no noise ! what a  surprise?!)

    The play of the axes is difficult to say - from my feeling not much...
    One axe runs with a rack the other one runs with a belt.

    hmm!
    do you have an idea what I can test?
     
  • RepetierRepetier
    So you proved noise is mechanical. Doe sit happen with bost axis if pure and is the same? It is hard to find a noise source remotely. Sinc eit is a plotter are there any loose parts holding pen etc that can be heard when changing direction or accelerating?
  • Georg99Georg99
    I removed all mechanics, just the motors are left. The noise is still there. The klick is between the G0 commands. My impression is that the movement starts with the klick.
    It happens with both motors (I connectied only one motor)
    I changed acceleration, speed, motordriver board - seems to be independent from the configuration.
    Comes the noise from the first start step of the motor movement?
    (motors are Nema 17 stepper motors 1.8°, typical 3D-printer motor, 1/16 micro stepping)
  • RepetierRepetier
    Motor start with a speed of jerk/2 so that could make a noise, but you said noise between moves. Between moves you might still have a jerk if you change direction and acceleration/decelleration to limit jerk. But these need to happen to make it move effectively.
  • Georg99Georg99
    The noise is between the G0/G1 moves.
    It is independent from the direction, eg G1 X10; G1 X20 (only X direction) makes the same "tack".
    I played around with jerk 0 to 10 .. that makes no difference (atleast what I can hear).
    I  tested now with manual control, the "tack" appears on start and end of each single movement.
    The motor is without power after the move ..

    Probably I can not change the "tacks" - I used the same equipment originally for a delta printer. In that configuration I cannot remember that sound (but eventually I overheard it, because the noise was in general higher)




  • RepetierRepetier
    Motor should have power after move. If not you have enabled to disable the motor and what you hear is then the sound from power on/off. Normally you want the xy to keep power. This was more meant for z axis with M8 rods where Z does not move even if power is off. For xy it is normally to dangerous to loose steps.
  • Georg99Georg99
    aha that might be the point! I will check...
  • Georg99Georg99
    yes, great now it is quiet! thanks for help!
    That was it - surprising that the power on/off makes noise ... I thought that I should switch off the motors to avoid heating, because the friction in my system will prevent to loose steps. But the motors are cold anyway...

  • RepetierRepetier
    Motors will never hold microsteps without power. They always fall back to closest full step without power. Soy ou get some movement then.
  • Georg99Georg99
    thanks for the info - (it is obvious, when I think about it) - So my plotter will win some accuracy!
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