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Filament stops flowing after 2.5 hours

Posted by gemors 
Filament stops flowing after 2.5 hours
July 24, 2018 12:58AM
Hi Guys,
As of late on big prints it seems like the filament is getting jammed after about 2.5 hours of printing. I’ve changed the nozzle from a .35 to a .5 and it is still happening. Nothing is being pushed out of the side of the extruder either.
I’m running a I3 Prusa from Geetech with a E3d hotend and as well as a Bowden conversion.

Any thoughts on why after 2.5.3 hours of printing it will stop extruding and clogging up?.

I've attached a couple of test prints of late.


Thanks

Edited 1 time(s). Last edit at 07/24/2018 01:00AM by gemors.
Attachments:
open | download - 222.jpg (486.7 KB)
open | download - 111.jpg (532.1 KB)
Re: Filament stops flowing after 2.5 hours
July 24, 2018 04:47AM
If you have an all-metal Mk8 extruder, the extruder motor can get so hot, that the extruder stops working reliable.
See heat creep, for tips to prevent overheating.
Re: Filament stops flowing after 2.5 hours
July 24, 2018 07:14AM
I was running the E3d at 220 Degress Celcius, could that have been to hot?
Re: Filament stops flowing after 2.5 hours
July 24, 2018 07:28AM
heat creep (since you clearly didn't look it up) is when the heat from the hot end moves past the heat beak and heats up the things around it.

Things that are meant to stay cool,, such as PTFE tubes, stepper motors, or plastic part in general.

Do you have a fan that blows on to the cooling fins of the hotend?

Do you have a fan on your electronics? In particular over the stepper drivers?

Edited 1 time(s). Last edit at 07/24/2018 07:29AM by Dust.
Re: Filament stops flowing after 2.5 hours
July 25, 2018 04:50AM
perhaps you should have read what I replied....
Re: Filament stops flowing after 2.5 hours
July 25, 2018 06:16AM
the temperature you run the hot end at is irrelevant, could be 5 degrees or 5000, its shouldn't get past the heat break. (on a suitably designed hot end)
Re: Filament stops flowing after 2.5 hours
July 31, 2018 12:53AM
Probably the most asked question in all of 3D printing is "why does the extruder stop extruding?"
First of all, be observant. does the extruder motor itself stop running? Is the filament getting eaten by the feeder? Do you hear any strange sounds?
Get a basic idea and think about whether it is more likely electrical or mechanical. Then you might have better luck with advice pertinent to the issue.
Good luck.
Re: Filament stops flowing after 2.5 hours
July 31, 2018 08:03PM
What @jdargot said. Plus...

Any time-related problem usually has heat-creep as the root cause. It could be stepper drivers getting hot, the extruder motor getting hot, or it could be heat creep in the hotend. Try the finger test on the stepper drivers (especially the extruder driver) and the extruder motor. If all's well, you should be able to hold your finger on them without getting burnt.

If there is a good heat-conduction path from the heater block up to the cold part (top) of the hot-end, and/or inadequate cooling of the cold part, and/or a poor heat-conduction path to the nozzle, then filament that is supposed to be cold gets warm. It swells, softens, and clogs the hot-end. Improper heat conduction is caused by improper assembly of the hot-end... search my old posts for proper assembly instructions.

I disagree with @Dust in that if your temperature is too high, heat can creep up the filament. That typically clogs when you do a retraction (e.g. when moving from one printing location to another) and warm, soft filament gets pulled up into the cold part of the hotend. You could try reducing or even turning off retraction -- the downside is that you then get increased stringing.

Exactly what type of filament are you printing? 220C is a bit hot for PLA (I use 195-200), but not for ABS. Try printing a temperature tower to find the minimum you can use, and go about 5 degrees above that, plus another 5 for your first layer.

Your photos don't tell me anything about possible jam explanations. They look like calibration cubes which would only take a few minutes to print? Photos of the large items that failed *could* be useful.

Some more information to gather:
  • You could try slowing your print down; that might be enough to let heat radiate from whatever was getting hot.
  • Or try pausing the print after an hour, allow everything except the hotend to cool (say 15 minutes), then resume. Does it still jam after a total of 2.5-3 hours printing time, or does it jam 2.5-3 hours after you resumed?
  • What exactly is your printer doing when it begins to jam? Printing some small, complex layer (with consequently lots of retractions)? Long straight pieces? Solid layers?
  • Does it always jam at the same height? Or the same X or Y position? Or is it purely time-based?
  • Is your extruder motor skipping? Or grinding?
Re: Filament stops flowing after 2.5 hours
July 31, 2018 10:03PM
Quote
Dust
the temperature you run the hot end at is irrelevant, could be 5 degrees or 5000, its shouldn't get past the heat break. (on a suitably designed hot end)

If the print temperature is low, it can be difficult for the extruder to push it out the nozzle, and that can lead to jamming.

If you use adequate print temperature but come to a part of the print that does a lot of retracting, and your retraction is too long, you can pull soft filament up into the heatbreak where it will cool and cause a jam.

Edited 1 time(s). Last edit at 07/31/2018 10:05PM by the_digital_dentist.


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