Can't print for long???

[flyntm 2]

I have a UM3.  It all started with a big print fail,  The Material backed upped into the head and in the process of trying to clean it up, I damaged the head.  Fortunately, I had a spare AA 0.4 head.  I installed the new head, loaded PLA and, as expected, it wanted to calibrate XY.  When it printed the test pattern the Y outline looked OK but then it started printing dots.  Kind of like the head wasn't getting fed enough material.  I have unloaded / loaded material  and tried to calibrate numerous times and it does the exact same thing.  I tried cleaning the head and the feeder and still get the same result. Immediately after loading, it starts out OK but, within a few minutes, it starts laying down dots.  

Another symptom I've found is that when loading material, it starts out coming through the head good but if I don't hit "Confirm" and let it run, the material will start coming out slower and slower. Eventually, the feeder puts a notch in the material and won't feed anymore.  I tried increasing the pressure on the feeder spring but that didn't seem to do anything. I have tried 2 different heads with the same results.  I have watched the temperature graph and the head appears to be holding the correct temperature.

I've run out of things to try.

 

Thanks for being patient enough to read all this,  If you have any ideas...

 

 

[Torgeir 248]

Hi @flyntm,

 

as it starts printing "normal" but soon loose feeding of filament flow, I would check that the front fan is working properly.

If this fan does not work properly (due to rest of filaments strings blocking the fan or broken electrical connection), the cold end of the nozzle will be to hot and make the filament stuck in the upper part of the of the head..

As you just have had all this filaments build up inside the head, it might be wise to check for this issue.

If this dose not work, you might check the feeder unit for proper assembly of the pressure wheel arrangement.

 

However, issues with the front cooling fan not working due to blocked fan have been reported in here several times.

 

Thanks

Torgeir

[flyntm 2]

I think you nailed it!  That fan has a broken wire.  Thanks for your help.

[Trlby 0]

I've had this happen to me a least a dozen times... The reason is the Front FAN and Core Door are

poorly designed. The worse part is Ultimaker doesn't monitor the Fans RPM so when filament hairs get caught in the fan blade, it simply STOPS, and the core(s) overheat.  So you get a "bulge" in the Filament from it's expansion in the top section of the core. This causes the the filament to stop advancing, which intern grinds the material in the Feeder make the whole damn thing useless.  But it just keeps printing away making a bigger and bigger mess while wasting time and money.

 

At least they could do is have a an LED behind the blades so one can see if the FAN is even moving. But even that won't help an overnight print... so now I'm stuck only printing during the daytime so I can check on it with a flashlight to make sure the Fan is spinning.

 

Ultimaker really needs to upgrade this part of the Printing Head... and while they're at it they should design an easier to attach and more effective Silicone cover for the Core nozzles.

Edited June 24, 2021 by Trlby

[chrismason 0]

Hi, I have a similar issue with my Ultimaker S5.

 

The front axial fan failed which resulted in the print core clogging up and ended up with a bulge of filament at the top of the print core. Iamge attached shows in the purple area where the bulge is.

 

I have now got a new front axial fan, installed it and its working fine.

 

The issue i have now, is that i can not remove the filament. I cant pull it up or down  because of the blockage bulge.

 

I also cant pull the print core put because the filament is stopping it from sliding out horizontaly.

 

does anyone know how I can get this out?

 

The only method I have found that might help me is this video: Ultimaker video on youtube

 

It seems do able, but if there is another way to get the filament out, without the need to completly dissasembkle the print head assembly. I would prefer not to risk taking it apart as the spring loaded  leveler bit looks like it could be tricky to put back together if it pops open.

 

Any ideas from anyone would be greatly appreciated.

 

[Smithy 1,144]

Try if it helps when you pull out the collet which holds normally the Bowden tube. 

[chrismason 0]

Hi, I got a responce from my Ultimaker support ticket.

 

The method that was recomended via the video here: Printhead PCB Installation (UM3/UM3X) - YouTube

 

This method was recomended along with a caviate that the print core should be heated prior to disasembling the print head assembly.

 

This sounds good, and I began the disasembly prior to switching off and unplugging the printer. I only had to disconnect the cable, undo the 2 rear screws which go through the full length of the assembly.

 

Byt the time I had removed the print corethe core had cooled, so removing the filament was difficult and additional heat was required. This solved the issue.

 

I then re-assembled the print head assembly, cleaned the cores, calibrated, performed maintenance and everything is now printing well again.

 

I hope this helps someone else if they have the same issue.

[Smithy 1,144]

Thanks for the feedback and I am glad you are back in business! 
 

Happy printing!

[Trlby 0]

Chrismason,

 

"It seems do able, but if there is another way to get the filament out, without the need to completly dissasembkle the print head assembly. I would prefer not to risk taking it apart as the spring loaded  leveler bit looks like it could be tricky to put back together if it pops open."

 

"Any ideas from anyone would be greatly appreciated."

 

In your picture you show an purple oval showing a small gap between the Core and the Case of the Printer head.

 

My disaster killed my Print Core to the point where it wouldn't even heat up.

So I took a piece of thin S.S. flat wire about a 1/4" wide and heated it up with a mini torch until it was hot, but NOT RED HOT. I then used it like a chisel and was able to cut through the Filament well enough to free the Core from the Print head carriage... and it worked like a charm.

 

This is one of many poor engineering issues with the Design of this Printer. There are numerous examples of the Engineering Team not looking at Maintenance issues when designing mechanical assembles that require maintenance or occasional disassembly. Another area is the Feeders... you are forced to relieved the tension (which nobody tells you) if you want to clean out the Knurled Drive wheel. So my first experience opening it, I had everything explode and parts went flying all over the place. Again poor instructions, but the real Engineering flaw is using the "flimsy" Split Molded Case as the resting point of the tension screw. So how short sighted is that?