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Sudden underextrusion during print


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Posted · Sudden underextrusion during print

Hi guys,

 

I have the problem that on long running prints I get underextrusion during the print. I'm using an Ultimaker 3 with standard AA 0.4 nozzles and PLA. At the beginning everything is normal and looks fine, but after some time underextrusion starts till in the end no material is extruded any more. 

Afterwards I have to clean my nozzle because it is clogged. I already checked the feeder, this is looking fine. I don't think that it is the material as this is not the first time this happens and not only with this material. Also it just happens in long running prints. I also checked the other nozzle, but there i have similar problems. 

 

Do anyone has any ideas left? 

 

Thanks in advance

20190114_111135.jpg

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    Posted · Sudden underextrusion during print

    My first advice would be the print core itself, but if you have changed it already to the other one, then something else must be the problem. 

     

    How fast do you print? I mean, if you print too fast, the feeder pushes the filament forward, but your nozzle cannot melt that amount of material in time and with the time, the nozzle gets clogged.

     

    How hot do your print?

     

    When you clean your nozzle, do you make cold/hot pulls as described in the maintenance guide?

     

     

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    Posted · Sudden underextrusion during print

    Thanks for your answer.

     

    I'm printing at 200°C at a speed of 80mm/s, which is the standard setting for the normal profile of a layer height of 0.15mm. 

     

    The cleaning I'm doing like described. 

     

    In my opinion the weird thing is that the print runs without any problems for 15 hours and then begins to underextrude. So I'm thinking that this problems somehow accumulates during the print.

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    Posted · Sudden underextrusion during print

    It is really strange, 80mm/s sounds much for the first moment, but yes it is the default print speed for the 0.15 profile, and actually, you just print infill with that speed, everything else is 30mm/s or 40mm/s which is ok.

     

    Which brand of PLA are you using? If it is some cheap China filament, it could be that the nozzle will be clogged with the time, or the filament diameter is not consistent over the spool.

     

    Another idea is, that if the spool comes near to the end, that the friction is much higher than with a new spool, could this be your problem?

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    Posted (edited) · Sudden underextrusion during print

    I'm using PLA from filamentworld, which is a german company. I measured the diameter and it was overall consistent at 2.8mm. So this seems fine.

     

    You're right, I am near to the end of the spool (I don't know exactly how much is left). So I will try again a print in the next days with the spool like it is and report afterwards. 

    Thanks for your help

    Edited by orlin278
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    Posted · Sudden underextrusion during print

    If this is the problem, then I would say, your feeder gears or the Bowden tube needs some maintenance. You should change the Bowden tube once per year or if you get problems. Maybe the friction inside the tube is too high and therefore you get problems.

     

    But if this is the case, I will not explain why you get a clogged nozzle.

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    Posted · Sudden underextrusion during print

    Hello @orlin278, could you please attach a project file that has failed. I would like to have a look at the settings. Thanks.

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    Posted · Sudden underextrusion during print

    @smartavionics, thanks for your help. I attached the model.

    The things i changed from the normal settings are the wall line count, the thicknesses and the in fill density concerning the PLA part. I also used a skirt instead of a brim.

    The support is also altered in multiple ways (overhang angle, support density, conical support from experimental settings), but this worked without any problems.

     

    Maybe one more thing. I already printed this model successfully once. Back then i used other support settings and a 3 lines instead of 2 and 1mm Top/Bottom Thickness instead of 0.7mm.

    BodySelfDesign_factor.3mf

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    Posted · Sudden underextrusion during print

    It's a little late for a reply, but maybe it helps somebody with similiar problems.

     

    I did a lot of testing, replaced the bowden tubes, tested other print cores and most of the time it worked in the beginning but after some printing it failed. 

     

    In my case it was something completly different. So the guiding wheel of the feeder in the back was coming apart. There are two pieces which are clipped together which are holding the ball bearing. As the came apart the guiding wheel was not on the correct axis anymore and at some point the feeder couldn't feed the correct amount, which leads to the material to stay to long in the hot end and clogging the core. 

    I replaced the part with a new one (found a 3D printed replacement online where the two parts are connected with screws) and from them on (2 months ago) I haven't had any problems. 

     

     

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