Maximum Acceleration of the MS

Discussion in 'Motion System' started by smoki3, Jul 17, 2020.

  1. smoki3

    smoki3 Active Member

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    Hello,

    I read the data sheet of the tool changer an saw that the movement parameters are defined as followed:

    So the max. acceleration is defined very low here. In the firmware which came with the printer with 6000mm/s².

    So which value is suitable?
     
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  2. p3t3rp4nd4

    p3t3rp4nd4 Active Member

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    I use the following settings on my own build of the ToolChanger:
    Code:
    M566 X400 Y400 Z8 ; Set maximum instantaneous speed changes (mm/min)
    M203 X36000 Y36000 Z1200 ; Set maximum speeds (mm/min)
    M201 X6000 Y6000 Z400 ; Set accelerations (mm/s^2)
    But with slightly diffrent Steppers for the XY movement:
    https://www.reichelt.de/hybridschri...17hs5425l2x2-p237910.html?&trstct=pos_9&nbc=1

    ... never had any problems so far and the ToolChanger has many hours on it.

    For the hemera direct tools, i have slightly diffrent setting which are applied within the tpre.g toolchange macros:
    Code:
    M566 X300 Y300 ; Set maximum instantaneous speed changes (mm/min)
    M203 X30000 Y30000 ; Set maximum speeds (mm/min)
    M201 X4500 Y4500 ; Set accelerations (mm/s^2)
    Hope this will help you.
     
  3. smoki3

    smoki3 Active Member

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    I use use the same as you.

    But how do you handle the switch the speed by a tool change?

    Do you completely handle this by tpost scripts?

    Would be nice if Reprap Firmware supports a command to set a percentage of the defined acceleration
     
  4. Nibbels

    Nibbels Well-Known Member

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    This is a very interresting topic.
    My other printers are quite stiff and heavy machines. On them the movable bed = y axis is ~1.2kg stock weight. And x axis is around 600-800g I guess. (Nema 17)

    On those printers 1500mm/s² (maybe .. 2000mm/s²) acceleration limit is a good choice. Jerk is best at ~ 10 .. 13 mm/s but as I understood it Jerk depends on weight and the spring tension of the system. (Jerk: I cannot compare the printers by guessing ...)
    I didtnt run any tests jet.

    The values I wrote into my config.g are just a good guess.
    As I only use direct drives on my TC I set the accelerations to
    M201 X2500 Y2000 Z500 C500 E2500:2500:2500:2500 ; Set accelerations (mm/s^2)
    for now.

    Did anyone run benchmarks for 400g or 500g toolheads on a TC?
    What about Jerk?
     
  5. p3t3rp4nd4

    p3t3rp4nd4 Active Member

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    In my tpre.g file for the hemera direct tools, i inserted the following commands
    Code:
    M566 X300 Y300 ; Set maximum instantaneous speed changes (mm/min)
    M203 X30000 Y30000 ; Set maximum speeds (mm/min)
    M201 X4500 Y4500 ; Set accelerations (mm/s^2)
    And in the tfree.g macos i inserted the commands for the standard settings i use
    Code:
    M566 X400 Y400 Z8 ; Set maximum instantaneous speed changes (mm/min)
    M203 X36000 Y36000 Z1200 ; Set maximum speeds (mm/min)
    M201 X6000 Y6000 Z400 ; Set accelerations (mm/s^2)
    I uploaded my RRF 3 config files with all the toolchange macros for my Hemera bowden V6 (T0), Hemera bowden Volcano (T1) and my two Hemera direct tools (T2,T3) and with the height adjustable brushes.
    Please use with caution!
     

    Attached Files:

  6. smoki3

    smoki3 Active Member

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    I do it the same way

    Then E3D should correct their data sheets :)
     

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