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Severe under extrusion and filament flow issues?


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Posted · Severe under extrusion and filament flow issues?


I am new to 3d printing. I have started working in my office and have taken over from another guy in doing the 3d prints on our ULTIMAKER ORIGINAL, using Slic3r.

Up until last week we had very clean, crisp prints. However in the last few days we have had serious issues with the prints. They were coming out under extruded or the fill wasn't meeting the edges. At first we thought this had something to do with settings, we fixed the problem temporarily, and then the prints got much worse.

What is now happening is the bed layer is extremely thin. 0.05 or something like that. The bed also contains gaps within the pattern and lines dont merge together but are rather independent of each other.

The prints are now also sticking to the glass heated bed because they are so thin!

We have adjusted the bed several times thinking it was out of alignment. We have also cleaned the nozzle with the atomic method, adjusted the spring of the feeder and cleaned the rough bolt in the feeder. This led to 1 or 2 initial lines which extruded fine. The rest of the print after that extruded extremely thin, and with the same problems mentioned before. I don't believe it is the settings anymore but rather an issue with the printer as these same default settings of ours printed just fine 1 week ago *with minor issues that seem perfect in comparison to what I have now.

The settings are

Ultimaker Original

Filament : PLA

Layer height = 0.2

First layer = 0.35

Fill Density = 40%

Solid Infill Threshold Area = 70mm2

Vertical shells = 2

Horizontal shells = top 3, bottom 3

perimeter_speed = 60mm/s

small perimeter speed = 60mm/s

bed_temperature = 45

bridge_fan_speed = 100

cooling = 1

disable_fan_first_layers = 3

extrusion_multiplier = 0.8

fan_always_on = 0

fan_below_layer_time = 60

filament_colour = #FFFFFF

filament_diameter = 2.85

first_layer_bed_temperature = 45

first_layer_temperature = 200

max_fan_speed = 100

min_fan_speed = 35

min_print_speed = 10

slowdown_below_layer_time = 5

temperature = 200

Current Super thin under extrusion #1


Current Super thin under extrusion #2



Example of 'gaps between the bed layers' and all subsequent layers on top. The darker patches are still thinner than normal, but look good by comparison.


Any and all help will be greatly appreciated!

Kind Regards,




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    Posted (edited) · Severe under extrusion and filament flow issues?

    I don't know this slicer so I don't know what the extrusion multiplier of .8 does exactly but it sounds like it would underextrude by 20%.  Are you sure that's correct?

    Too cold, too fast.  Your bottom layer is .35mm thick, with .4mm nozzle and 60mm/sec that is 8.4 mm^3/sec.  much too fast for 200C.  Try 240C if you are going to print that fast or slow it down to maybe 10mm/sec for the bottom layer, then 20mm/sec for the rest.  The UMO can print that fast at 240C but you are still pushing it a bit.  I recommend you print at half maximum speed as shown below.  For the bottom layer of course it's almost twice as thick so print half these speeds...

    Here are my recommended top speeds for .2mm layers (twice as fast for .1mm layers):

    20mm/sec at 200C

    30mm/sec at 210C

    40mm/sec at 225C

    50mm/sec at 240C

    The printer can do double these speeds but with huge difficulty and usually with a loss in part quality due to underextrusion. Different colors print best at quite different temperatures and due to imperfect temp sensors, some printers print 10C cool so use these values as an initial starting guideline and if you are still underextruding try raising the temp. But don't go over 240C with PLA.

    Edited by Guest
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    Posted · Severe under extrusion and filament flow issues?

    Hi GR5

    That worked really well. Thank you! Not sure why my previous settings which worked stop working, but I understand the principles of your advice.

    The print still however has the gapped streaks in the base.


    Do you have any idea how to fix this?




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