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Inconsistent Extrusion  

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Allanimal
(@allanimal)
Eminent Member
Inconsistent Extrusion

I've had my Mk3 for a few months now, and it worked great for a while, but I am now having many extrusion issues.
Sometimes things work OK for a while, but eventually it will stop extruding entirely.

As an example, here is a test print - the oval should be completely filled in, but instead I am getting this striping effect.

Also often during a print, the printer will pause, move extruder will move the the front right corner, beep and request I remove filament and then re-introduce the filament. Usually when this happens, even though the filament will appear to load and extrude, it will usually fail to continue to print - either it will happen again in a minute or two, or it will not extrude at all and the print is wasted.

I have changed nozzles, unclogged the nozzle in various ways, adjusted the tension on the extruder idler, and other maintenance. It happens with at least two different brands/colors or PLA. I don't have any other materials to try.
I just can"t figure out what to do next to fix this... Any ideas what could be causing it and how to fix it?

Posted : 09/06/2018 5:29 pm
OneThou
(@onethou)
Member Moderator
Re: Inconsistent Extrusion

I sometimes see extrusion problems once a fresh filament spool has been in the open for several weeks. Also, assuming that's PLA in the picture, that amount of stringing looks somewhat unusual to me. For these reasons, I'd suggest to experiment with some filament-related settings since you've already ruled out all kinds of printer issues. Specifically, I'd run some tests with an increased extrusion multiplier (like, 1.25 instead of 1 to see how it reacts), and/or increased temperature (towards the upper limit recommended for your brand).

Posted : 09/06/2018 11:20 pm
Allanimal
(@allanimal)
Eminent Member
Topic starter answered:
Re: Inconsistent Extrusion

Thanks for your reply. I'll try your suggestions when I get a chance and get back with the results.

Posted : 10/06/2018 4:33 pm
Allanimal
(@allanimal)
Eminent Member
Topic starter answered:
Re: Inconsistent Extrusion


I sometimes see extrusion problems once a fresh filament spool has been in the open for several weeks. Also, assuming that's PLA in the picture, that amount of stringing looks somewhat unusual to me. For these reasons, I'd suggest to experiment with some filament-related settings since you've already ruled out all kinds of printer issues. Specifically, I'd run some tests with an increased extrusion multiplier (like, 1.25 instead of 1 to see how it reacts), and/or increased temperature (towards the upper limit recommended for your brand).

So, I tried the easier of the two suggestions and tried printing at a higher temp. I was already printing at the recommended temp of the filament manufacturer, but tried at +10°C. The print was pretty good, with much less stringing than before. I'm trying again now, with +20°C.
I was under the impression that stringing happened at too high temps, not too low.

At any rate, it would seem that maybe my thermistor is off, and my nozzle is actually quite a bit lower than the reported temperature.

Posted : 10/06/2018 6:42 pm
Allanimal
(@allanimal)
Eminent Member
Topic starter answered:
Re: Inconsistent Extrusion



I sometimes see extrusion problems once a fresh filament spool has been in the open for several weeks. Also, assuming that's PLA in the picture, that amount of stringing looks somewhat unusual to me. For these reasons, I'd suggest to experiment with some filament-related settings since you've already ruled out all kinds of printer issues. Specifically, I'd run some tests with an increased extrusion multiplier (like, 1.25 instead of 1 to see how it reacts), and/or increased temperature (towards the upper limit recommended for your brand).

So, I tried the easier of the two suggestions and tried printing at a higher temp. I was already printing at the recommended temp of the filament manufacturer, but tried at +10°C. The print was pretty good, with much less stringing than before. I'm trying again now, with +20°C.
I was under the impression that stringing happened at too high temps, not too low.

At any rate, it would seem that maybe my thermistor is off, and my nozzle is actually quite a bit lower than the reported temperature.

The print at +20°C had almost no stringing... I’ll try with something real instead of just this test object.

Posted : 11/06/2018 12:10 am
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