Printing parts – Estimated print times wildly inaccurate

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This topic contains 10 replies, has 5 voices, and was last updated by  Alex Hodge 1 year, 2 months ago.

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    Alex Hodge

    I guess I’ll start off with the printer that I’m using. It’s a Wanhao Duplicator i3 with a few upgrades (nothing that would change my stock printing speeds, just quality of prints). If you’re not familiar with this printer, it’s a very popular and very common Cartesian printer based on the Prusa i3 (also very popular and very common). So I’d expect that my print times would be somewhat close to the estimates. The only guidance I see is the infill %, which I have used on every part as specified. Still, every part I print is taking twice as long as the estimates. So I figure I must be doing something wrong in my slicing. I’m using Simplify3d, but I tried Cura as well and had basically the same results. For some of these parts I’m using supports. While that adds some time to the print, it’s not enough to account for the disparity. Anyway here are some details. Maybe someone has an idea of what I’m doing wrong here.

    Default Printing Speed 3600 mm/min
    Outline Underspeed 50%
    Solid Infill Underspeed 75%
    Support Structure Underspeed 65%
    X/Y Axis Movement Speed 4800 mm/min
    Z Axis Movement Speed 1000 mm/min

    C-Roller W/ Support 55% infill
    Build time: 11 hours 3 minutes
    Filament length: 31847.8 mm
    Plastic weight: 76.60 g (0.17 lb)
    Material cost: 1.69

    C-Roller W/O Support
    Build time: 9 hours 32 minutes
    Filament length: 28646.1 mm
    Plastic weight: 68.90 g (0.15 lb)
    Material cost: 1.52

    I’m using .1mm layer height. 6 top layers, 6 bottom layers, 4 shells. Start points optimized for speed.
    My infill is Full Honeycomb for strength.

    So does anything jump out at anyone? I’m using less filament than estimated and taking at least twice as long to print. My parts are coming out very nice and very solid…It’s just taking ages to print them all.

    I use these basic settings for most everything I print and typically only change the infill % depending on what I’m printing. I’ve never considered my prints slow, but maybe I don’t know any better.



    Repetier has print time calibration settings.

    Those times are never going to be very accurate. It is only making a guess on you print and travel speed. It does not factor in all the accelerations and deceleration. They get even further off if you are printing multiple objects at once. It then embeds the times into the gcode so if you speed it up or slow it down manually the time will not adjust its just kinda of a gimmick.

    Now you know the time are about twice what it says.


    Alex Hodge

    Ok fair enough. Out of curiousity, what printer do you use? Are you getting close to those time estimates? I’d guess you’re printing parts on MPCNCs. I’m excited for the possibility of a much larger print area. I’m planning on putting an E3D V6 and Titan extruder with a pancake stepper motor on the MPCNC for larger area prints.


    Jakob A

    Umm, maybe the layer height ? šŸ™‚



    Wow! .1mm layer heights will take forever! Most of my structural stuff I print at .3mm, and “pretty” stuff I print at .1mm, or .2mm, usually 2.


    Alex Hodge

    So, I typically run .1 for quality. And I want my parts to be strong AND look nice. Maybe I should experiment with .2, it would cut my print time in half LOL!


    Alex Hodge

    You’re not kidding they take forever! This should be done in an hour or so hopefully, I’ll start another one with .2 and then compare the two when they’re done.



    Alex Hodge

    I guess to some degree that makes sense. As your layer height decreases, your layer count goes up. So, you would have more layers to possibly separate if using a lower layer height. Well, now I’m really glad I posted this up. Thanks guys!



    I found the print time estimate to be pretty much dead on for me. I also used .26 as the layer height and the parts look great.

    I too was misguided and thought that a lower print height was stronger, when in fact a larger layer is stronger.


    Alex Hodge

    Just a quick update for everyone. Printed at .2 my parts are finishing almost exactly on the money based on the estimates. They’re coming out almost indistinguishable from my .1 prints, just requiring a tiny bit of cleanup whereas my .1 prints came out finshed. Thanks everybody for your help getting my mind wrapped around this. Maybe some more printing guidelines besides infill % should be added to the documentation to remove all doubt. Recommended infill %, infill pattern and layer height maybe? Anyway, Thanks again guys!

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