Filament feeding stops after a few minutes of printing - UM3

[fw101 0]

The PLA filament stops feeding after a few minutes of printing.

I would like your opinion on what the cause could be.

My guess is: 1) filament gets too hot in the core causing it to expand too much and ends up jamming in the core's cool section, or 2) heat cuts out for some reason during the print causing the filament to cool too much in the core.

 

The UM3 setup I am using is shown in 00-setup.png.

I am using the 2.85 mm PLA filament.

Print temperature is 195 C and print speed is 70 mm/s. Fan speed is 100%.

The filament stops feeding near the end of the first layer. See 01-layer1-actual.jpg and 01-layer1-Cura.png.

When the filament jams, I cut the filament before the feeder then pull the Bowden tube containing the filament section off the UM3.

A photo of the filament section in the core is shown in PLA-filament.jpg.

 

Other observations: 1) the front fan often is not turning, 2) the LED on the PLA core starts off red and then goes to blue. Not sure it cycles between red and blue.

 

Thanks for any help with this problem.

 

 

[gr5 2,265]

The front fan is a very serious issue and could explain everything.  Remove the rear 2 screws on the print head and the rear cover will pop off easily.  Push down firmly (with the head in a corner so you don't bend the rods) on the connector in there and see if that fixes the fan.

 

Also how many hours are on that core.  The teflon may have gotten old if it's say 2000 hours or more.  Under 500 hours I'd say no way.

[fw101 0]

Thanks for the advice about the fan connector. I will check it.

Just to be sure I understand what you are saying, are you referring to the procedure described in https://ultimaker.com/en/resources/50882-replace-the-axial-fan?

 

The core has less than 500 hrs on it. 

 

[gr5 2,265]

No!  That's much more complicated.  There are 4 screws higher up on the head.  Perfectly symmetrical in a square.  Remove the 2 towards the rear.  That will not do much other than give you the ability to remove the rear half of the top of the head.  It's a small flat rectangular piece of plastic - similar to a battery cover.  That will give you access to a connector - if the cable comes partly loose (very common with UM3!!!) one possible failure mode might be the front fan not working.

 

If the front fan doesn't work then one would expect the filament to overheat above the heat break (after a while - maybe 10 to 40 minutes) and swell up and get jammed.  Especially if there are lots of retractions which help move the heat upwards in the core.

 

 

[Haliisme 0]

I have also been having this problem and have figured out that the fan settings aren't being translated to the machine properly. When I start the print in the 'tune' setting the fan is at 0% even though it is 100% in Cura, I have found manually raising that to 100% in the tune setting solves the heat creep/clog issue. 

 

Good luck, hope this helps! 

[Smithy 1,146]

4 minutes ago, Haliisme said:

have figured out that the fan settings aren't being translated to the machine properly. When I start the print in the 'tune' setting the fan is at 0% even though it is 100% in Cura

Have you set the fan speed also to 100% for the first layer? In Cura are separate settings for the first layer and the rest.

[fw101 0]

Thanks to all who replied to my question.

 

I checked the connectors to the fans. They were OK.

 

Next, I verified what the Cura settings were for the cooling by exposing other parameters in \Settings\Configure setting visibility\Cooling.

The 'Regular Fan Speed at Layer' was set to 4 as a default.

So, I made the following changes to the Cooling settings:

Fan Speed = 100%

Regular Fan Speed = 100%

Initial Fan Speed = 100%

Regular Fan Speed at Layer = 1

 

With the changes to the Cooling settings, I was able to successfully make the print.

 

I noticed that the front fan did not turn on at all and the LED on the AA core always stayed blue. 

There was no apparent effect on the print though. Not sure it is normal behavior or not.

 

[Smithy 1,146]

The part fan is usually set to 0% for the first layer, because you want little or no cooling there, so the first layer adheres well to the glass.

 

The middle fan is responsible for cooling the print core and cannot be controlled via Cura. This fan starts automatically as soon as the Printcore exceeds 40°. If the fan is not running during printing, you should try to fix it. If the middle fan does not work, the heat in the Printcore climbs higher and higher and at some point no more filament can be transported.