Slow prints

Discussion in 'Calibration, Help, and Troubleshooting' started by Falc.be, Apr 4, 2016.

  1. Falc.be

    Falc.be Well-Known Member

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    I am not sure whether its an actual problem with S3D or my printer but print time is 2-3 times slower than what S3D calculates.

    the print quality is pretty good, but the speed seems off

    Has anyone noticed this ?
     
  2. Kanedias

    Kanedias Well-Known Member

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    I find it to be off by a 10-30% only. But then I've also found I can twist the FR on the printer up to 130% with no appreciable loss of quality so it works out ok :D
     
  3. Pierce

    Pierce Well-Known Member

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    Yes, I had a thread about this as well. Try a vase mode print of something simple and the times will be pretty close. I believe the acceleration or jerk settings are more limiting than simplfy3d could guess so that's what's causing the disconnect. I generally double any estimates I have if print is complex
     
  4. Falc.be

    Falc.be Well-Known Member

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    thats actually a big downer for me, it makes the printer allot slower than my old one
     
  5. Pierce

    Pierce Well-Known Member

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  6. Falc.be

    Falc.be Well-Known Member

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    I compared those settings with my ultimaker, some where ten times higher

    4h37 on a 2h50 print , its almost 65% extra

    You can easily deduce that print speeds are a mere 20 to 25 mm/s instead of the promised 50 mm/s

    I will try a print at 50 mm/s and one at 25 mm/s realy wonder what the difference will be
     
  7. R Design

    R Design Well-Known Member

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    a) remember that Simplify3d has a number of "underspeed" settings including for "perimeters" and infill. New users don't notice these and that a lot of things are slowed down by parameter;

    b) on shorter moves no printer reaches "top speed" and the time for the manoevre is very much related to ACCELERATION; of course it is true that the Ultimaker has phenomenal acceleration..... (due to the fact the print head weighs about as much as a grape)
     
  8. Falc.be

    Falc.be Well-Known Member

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    I had already adjusted those settings accordingly, I do have experience with it.

    I was printing both the rear y axis braces, these are no small pieces.

    fact is, with the current settings, the printer is nowhere near capable of the average 50 mm/s printing speed that was promised.

    Even the benchy with the standard PLA profile took 1h45 instead of 1h15
     
  9. Pierce

    Pierce Well-Known Member

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    I printed a vase in spiral mode that was almost a square, print time was very close, so I don't think speed is an issue and it is reaching 60. As R Design says it's limits in jerk and acceleration which is causing any print with lots of turns or changes in directions (like infill...) to slow down as simplify3d doesn't know the jerk or acceleration limits of your printer. I think that if we increase some of these limits we will see print time improvements but at the possible cost of lower print quality.
     
  10. PsyVision

    PsyVision Moderator
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    Pierce and Sarah Nicholson like this.
  11. Kanedias

    Kanedias Well-Known Member

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    I guess it just means the default profile is set to very conservative speeds. You can keep increasing them yourself to see how fast it'll go before it affects print quality.
     
  12. Falc.be

    Falc.be Well-Known Member

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    Ok I have done 4 testprints with 4 different speeds

    I have printed the Y axis cable bracket with identical settings except the basic print speed
    Speed / Calculated / Actual print time / Difference in %
    29 mm/s / 38 mins / 45 mins / 18.42 %
    35 mm/s / 32 mins / 38 mins / 18.75 %
    50 mm/s / 23 mins / 34 mins / 47.8 %
    60 mm/s / 19 mins / 32 mins / 68.4 %

    All 4 prints have absolutely no difference in print quality and it also happens with the vanilla PLA profile

    So @Greg Holloway , whats going on ? this is nowhere near the promised 100 mm/s
     
  13. Greg Holloway

    Greg Holloway Administrator
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    One word | Acceleration.
     
    mike01hu and Pierce like this.
  14. Falc.be

    Falc.be Well-Known Member

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    I am actually looking for an explanation on why it was tuned so low ? Are there mechanical reasons, electronics ?
     
  15. Kick2box

    Kick2box Well-Known Member

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    Was done to leave room for successfull experiences to kickstarter backers! :D
     
  16. Pierce

    Pierce Well-Known Member

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    @Falc.be can you try this if you get a moment to see if our times are aligned, download this part: http://www.thingiverse.com/thing:18672 scale it to 50% or something and print in vase mode.
    My time was within minutes of the estimate as its generally pretty straight lines so not affected as much

    That will hopefully convince you that its just the acceleration settings rather than anything else!

    Also change infil to rectinliner rather that triangles for less changes in movement :)

    @Greg Holloway any recommendations for experimenting with acceleration and jerk settings?
     
  17. R Design

    R Design Well-Known Member

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    Tom has done a piece on this:



    The default settings are obviously our starting point and it's trial and error all the way up from there.

    Presumably the Titan will enable dual users - all things being equal - to accelerate faster? With a bit of luck I'll be able to mount a lightweight geared extruder on my Pro too!

    btw. max speed is currently firmware limited to 150mm/s. We can play with that too. But only relevant on the long straights.

    Another data point: Richrap does his long big prints at 70mm/s.... (Which are pretty much all perimeter - little / no infill.) Probably the speed-limiting factor there is print quality....
     
    #17 R Design, Apr 6, 2016
    Last edited: Apr 6, 2016
  18. Greg Holloway

    Greg Holloway Administrator
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    You can change any numbers you want guys & gals. I'd suggest small increments.

    The disparity between the S3D print time and the actual print time is due to acceleration. It assumes full print speed for all motions.
     
  19. Henry feldman

    Henry feldman Well-Known Member

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    Well, when the UltraBigBox comes out, we can use NEMA 42s which will take care of that little acceleration issue!
     
  20. R Design

    R Design Well-Known Member

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    Using a standard 0.4mm nozzle and extruding at the default 0.48mm extrusion width and X mm/s ?

    Want a 50% speed bump, independent of acceleration?

    Try a 0.48 * 1.5 = 0.72mm extrusion width!

    (Richrap pointed out that the flat bit at the tip of the nozzle allows you to extrude up to 2.5 times nozzle width. I haven't gone that far, but a modest increase gives all the plastic-related advantages of a nice steady extrusion and brings no (motion or plastic related) speed artefacts!)
     

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