kevin.c20
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Mk3 underextrusion with Slic3r?

Sun Feb 18, 2018 6:34 am

First 0.05 mm print on my Prusa Mk3, no clue what's wrong, appears to be some underextrusion, it was sliced through Slic3r prusa edition using the default 0.05 profile with infill reduced to 20%, combining infill every 4 layers, and support material enabled with detect bridging perimeters enabled too.

printed with the silver PLA that came with the printer and the Prusa PLA profile

Image
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just did another print at 0.15 mm this time slicing through Prusacontrol with default settings and supports enabled and it turned out just fine.

also printed with the silver PLA that came with the printer and the Prusa PLA profile

just started another 0.05 mm version sliced through prusacontrol before i head off to bed, I guess won't learn, fingers crossed! will update tomorrow!
Image

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joan.t
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Re: Mk3 underextrusion with Slic3r?

Sun Feb 18, 2018 8:18 am

I understand that the Mk3 is not good at 0.05 layerheight, the Bondtech extruder gears are larger than previous extruder gears, and it is difficult to get good control of the tiny extruder movements required at this layer height...

I have never tried it, but I have herd that 0.07 layer height is just about printable... with the Mk3

Having said that I haven't tried 0.05 layer height for ages.

regards Joan
I try to make suggestions that I believe to be well founded and safe,You should understand the context and ensure you are happy that they are safe before attempting to apply my suggestions,
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ewout.s
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Re: Mk3 underextrusion with Slic3r?

Sun Feb 18, 2018 6:12 pm

Same results here unfortunately, mostly. Haven't bottomed it out yet but very small prints seem to end up being fine from start to finish. Larger prints (i.e. normally sized) seem to start fine and then go awfully wrong, much like your first picture where the feet seem good. My theory was that pressure slowly builds up in the extruder until it reaches a critical magnitude and things start go wrong.

I have read what Joan mentions as well and it makes sense. Theoretically, if the extruders are the root cause then I would expect to see similar flaws manifest themselves when printing at standard layer heights and veeeery slowly as that would slow the extruder motor down. Many theories here but no evidence to support any of them, or much experience :roll:

Currently too busy trying to tune my first layer evenly across all bed locations for large prints to dive into the 0.05mm layer issues for small prints but will definitely have a closer look at this when time allows :)

stuart.b4
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Re: Mk3 underextrusion with Slic3r?

Sun Feb 18, 2018 9:40 pm

joan.t wrote:
Sun Feb 18, 2018 8:18 am
I understand that the Mk3 is not good at 0.05 layerheight, the Bondtech extruder gears are larger than previous extruder gears, and it is difficult to get good control of the tiny extruder movements required at this layer height...
The attached had all these exterior parts printed at 0.05 so I haven't found that to be true in my experience.
IMG_1431[1].JPG
IMG_1431[1].JPG (2.87 MiB) Viewed 189 times

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