mm/s vs mm/min



  • Hello,

    I tried the latest release of Slic3rPE to be able to use the new 'send to duet' feature, and I noticed something weird.

    When I started the print, the head moved very very slowly. I discovered that Slic3rPR now add some limits, at the beginning of the gcode file:

    M201 X9000 Y9000 Z500 E10000 ; sets maximum accelerations, mm
    M203 X500 Y500 Z12 E120 ; sets maximum feedrates, mm/sec
    M204 P1500 R1500 T1500 ; sets acceleration (P, T) and retract
    M205 X10.00 Y10.00 Z0.20 E2.50 ; sets the jerk limits, mm/sec
    M205 S0 T0 ; sets the minimum extruding and travel feed rate

    Problem: Duet M203 and M205 expect mm/min, not mm/s! Is it a bug in Slic3rPE, or do they really use mm/s in their firmware? What about others? Would be nice to all use the same units (mm/s would be better).



  • Is that being added in a custom gcode field?

    It's been possible to add those speed values so that the print time estimate can be more accurate for a while now. They use mm/s. I've just added a semicolon to comment out the commands. The estimator still reads them.

    https://github.com/prusa3d/Slic3r/releases/tag/version_1.39.1-alpha

    You can read about their print time estimator here



  • These values are defined under Printer settings. They can't be disabled, so you really need to enter the correct values, in mm/min, not in mm/s.



  • But they use M205 for jerk, not M566...



  • I hope they add a switch to use those values for the estimator only

    @Phaedrux Latest versions have a special page to set those. And no way to disable them. And if you put in 0 you get 0 in the gcode file.



  • I tried to set 0 too 😉



  • Oh that's too bad. I haven't looked at the newest version yet. I know they were adding some printer profile stuff. I wonder if there is a feature request open already to better support reprapfirmware.



  • @fma I just tried 1.41 and I can't seem to get it to generate the values like you describe.

    Is there some checkbox I'm missing to get it to do this?



  • Ok, I found it generates these lines if you use 'Marlin' flavor G-Codes (maybe with others, but I didn't try). No generation with RepRap/Sprinter.

    BTW, Slic3rPE estimated the print to 3h, and it took 4h!



  • Ah, that makes sense.


  • administrators

    @fma said in mm/s vs mm/min:

    Ok, I found it generates these lines if you use 'Marlin' flavor G-Codes (maybe with others, but I didn't try). No generation with RepRap/Sprinter.

    BTW, Slic3rPE estimated the print to 3h, and it took 4h!

    Have you tried running it in simulation mode?



  • Nope... I will do that.



  • @fma said in mm/s vs mm/min:

    Slic3rPE estimated the print to 3h, and it took 4h!

    I've found that when I have the speed, acceleration, and jerk settings set to match the firmware the estimate is usually within 15 minutes of actual print time. Same with Cura.



  • @fma awesome, this works. I was removing the lines manually for the first two i did but figured i would look it up. Thanks for figuring it out 🙂


  • administrators

    Firmware 2.02RC3 supports the use of M205 to set jerk, in mm/sec.


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