Ender 3 ... Can Duet or Duet/Klipper achieve 80+ mm/s?



  • I'm currently printing most objects with the default Cura Rough Draft profile which has speeds of 30mm/s outer wall, 60mm/s inner walls/infill, and 120mm/s travel speed. Someday I'd like a Voron or something which can go a lot faster but until then, is it possible to print faster, 80-120mm/s with the Ender 3 and still have the same quality prints on "Rough Draft" prints?

    If not with the RepRap config, would Klipper help? I've read some arguing Klipper is unnecessary with the Duet but isn't Klipper better for high speed because of it's physics calculations which allow maximum last minute deceleration and acceleration out of corners, etc. with minimal compromise to quality?



  • Klipper will help you when you have an 8bit board, but IMHO it doesn't add much on 32bit boards like the Duet.

    The duet board should easily be able to drive a Cartesian build at high speed, but it depends on the mechanical quality of the frame whether this is possible

    Other limitations are the ability of the hotend to melt plastic fast enough (should be OK) and the extruder to move the filament fast enough -- I highly doubt the stock extruder on the Ender 3 that is injection moulded plastic will be able to deal for a long time).

    Anecdotally, I did run a CR20 at way too high speeds on a 32bit board (Max feedrate 2500mm/sec and acceleration at 1000mm/s² -- don't ask (-: -- please mind those speeds were never attained due to the short moves involved in printing a benchy) and the print was fine until it got thrown off the bed due to plastic warping up and lack off enough zhop on retraction (see below). As the CR20 is very similar to the Ender 3, your target 80mm/s may be attainable with a duet, but you may need to tweak both the mechanics and the configuration to get usable prints.

    0_1558979945318_IMG_20190527_195444.jpg



  • @bugsysiegals Duet hardware and firmware won't be the limiting factor. For info, this is me doing "Real world high speed printing" using Duet hardware and firmware. https://www.youtube.com/watch?v=rUV5IZxfAxU
    300mm/sec from about 9 minutes into that video.

    Explanation and results discussions on my blog here https://somei3deas.wordpress.com/2018/10/14/real-3d-printing-at-high-speeds-and-even-higher-melt-rates-with-a-large-nozzle/



  • @oliof Thanks for your reply. Do you have any recommendations for a replacement extruder? Is it better to set exact max speed, accelleration, jerk values in config file or set them high and then enable acceleration and jerk control in Cura where you define these settings specifically under different profiles?



  • @deckingman wow, that thing was really moving, thanks for sharing!



  • Regarding extruders, it's a matter of preference, but a lot of people swear by dual gear extruders like the bondtech ones for maximal extruder force. I just went with an aluminum one and was capable of getting 150mm/sec on longer straight lines (beyond that the standard heatblock won't be able to melt the filament fast enough and you will get underextrusion).

    Regarding speed/acceleration/jerk settings I personally dislike the extra limits set by cura because they make gcode nonportable between different printers (in the sense that you impose another printer's limits when that may be inappropriate) and even if you have only a single printer they defeat the ability to tweak these values live during a print.



  • @oliof said in Ender 3 ... Can Duet or Duet/Klipper achieve 80+ mm/s?:
    ............................................

    Regarding speed/acceleration/jerk settings I personally dislike the extra limits set by cura because they make gcode nonportable between different printers (in the sense that you impose another printer's limits when that may be inappropriate) and even if you have only a single printer they defeat the ability to tweak these values live during a print.

    I second that sentiment for the same reasons. Nothing against Cura - Slic3R PE also does that and worse IMO.



  • @oliof said in Ender 3 ... Can Duet or Duet/Klipper achieve 80+ mm/s?:

    Regarding speed/acceleration/jerk settings I personally dislike the extra limits set by cura because they make gcode nonportable between different printers (in the sense that you impose another printer's limits when that may be inappropriate) and even if you have only a single printer they defeat the ability to tweak these values live during a print.

    It's a trade off, to be sure. Personally I never treat gcode as portable to begin with. I'm going to reslice for a number of reasons anyway. I like to be able to fine tune the slicer settings for each print move type. I see it as an extension of the speed control per move. Would you give up the ability to set independent speeds for external perimeters and infill? I see giving up control over independent acceleration and jerk in the same way.



  • Fair point, but for some reason I see acceleration and jerk as "machine side" while speeds for parts are "slicer side". It's probably as false a dichotomy as any (-;



  • @oliof When all gcode settings can be modified on the fly, why stop at jerk and acceleration?



  • @oliof said in Ender 3 ... Can Duet or Duet/Klipper achieve 80+ mm/s?:

    Fair point, but for some reason I see acceleration and jerk as "machine side" while speeds for parts are "slicer side". It's probably as false a dichotomy as any (-;

    I tend to agree. If you always use the slicer to set the accelerations and jerk values, then it's not an issue. But my concern about slicers changing configured acceleration and jerk settings is what state the those settings will be left in at the end of a print, and therefore what they will be when I start another print, possible with a "historically sliced" gcode file.

    Slicers have no means of knowing what my configured accelerations and jerk values are, so they can't restore those values at the end of a print. Therefore any subsequent "historic" gcode files that were sliced using configured default values will get printed at other than intended acceleration or jerk values, depending on what state the previous printer left the acceleration and jerk settings at (until power is cycled or the firmware re-booted).

    So they need to be either exclusively set for every print using config.g or exclusively set using the slicer but not a combination of both.



  • @deckingman M98 Pconfig.g in end.g to reset all values to firmware defaults?



  • @phaedrux said in Ender 3 ... Can Duet or Duet/Klipper achieve 80+ mm/s?:

    @deckingman M98 Pconfig.g in end.g to reset all values to firmware defaults?

    Yes I guess. But re-loading config.g more or less forces a re-boot doesn't it? I suppose there is nothing to stop one having a macro that just sets jerk and accel values to config.g values and running that. But it's a lot a f*rting about.

    TBH, I've played around a bit with so called advanced acceleration control and only ever get worse results than if I leave it all the same. I've even gone back to using the same basic speeds for everything wherever possible. The only thing I set to print slower are small perimeters (holes) and top solid infill. For whatever reason, I get better results keeping speeds and accelerations as near constant as possible. My hot end just doesn't do rapid changes in flow rate. But that may be because I tend to print faster than most people, so I probably have more residual hot end pressure which tends to have a damping effect on flow rate changes.



  • @deckingman I don't think reloading config.g would force a reboot, since it's just a macro file like any other. Editing it on the DWC does prompt for a reboot, but I don't think there is anything inherent within config.g that would require a reboot.

    I think your results make a lot of sense based on your printer. My extruder is probably on the opposite end of the spectrum for responsiveness. I think it's a good thing there are options and dials to turn to fit the gcode to the machine.



  • @phaedrux said in Ender 3 ... Can Duet or Duet/Klipper achieve 80+ mm/s?:

    I think it's a good thing there are options and dials to turn to fit the gcode to the machine.

    Yes agreed. Every machine is different and every user has their own preferred way of doing things, so the more "options and dials" the better (as long as people are able to choose whether or not use them).


 

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