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Filament not extruding

Posted by legoset0 
Filament not extruding
January 05, 2017 04:34AM
I was having dots on the side of the print and often gaps between layers which seemed to go away by increasing the temperature. I then had problems where filament wasn't always extruding. the filament now will normally extrude fine but then after a short time it will stop, the gear continues to spin but no filament is pulled in or extruded.
The printer is a geeetech prusa i3 with a mk8 extruder which doesn't have a tension adjustment. I can create pressure on it which sometimes helps and sometimes doesn't, even if it does it normally ends up stopping.

Edited 1 time(s). Last edit at 01/05/2017 04:34AM by legoset0.
Re: Filament not extruding
January 05, 2017 12:07PM
There are replacement extruders with tensioner for the idle gear on thingiverse. But you'd be lucky, to print one if the problem is as serious as it sounds.
Maybe you even find an all_metall_version for 10 bucks on the bay.

Edited 1 time(s). Last edit at 01/05/2017 12:09PM by o_lampe.
Re: Filament not extruding
January 05, 2017 07:42PM
Re: Filament not extruding
January 06, 2017 04:25AM
Yup, they are all similar. The second one comes without Bowden tube pushfittings, but you probably don't need them anyway.
Re: Filament not extruding
January 06, 2017 07:32AM
Since this was extruding OK at lower temperatures you shouldn't assume just changing the extruder so you can increase the idler load will solve the issue.
I would be looking at the temperature effects. Sounds like the higher temperature is causing the hot end jam. So we need to confirm there is no strange installation issues such as a short heat break tube, insufficient insertion of the heat break tube into the mounting block, PTFE tube correctly fitted etc.
Are you using a Bowden?
Can you post a pic of the hot end?
Re: Filament not extruding
January 06, 2017 08:09AM
this is the side of the print when it does work, this might help identify the problem. I will get a photo of the hot end tomorrow and experiment with temperatures a bit.


Edited 1 time(s). Last edit at 01/06/2017 08:10AM by legoset0.
Re: Filament not extruding
January 07, 2017 03:51AM
MCcarman is right, the main reason for your print failure is heat creeping, but the all metal hotends deal much better with radiating heat, than the crappy plastic version you have now.
So using a new one is a win-win for you.

Edited 1 time(s). Last edit at 01/07/2017 03:52AM by o_lampe.
Re: Filament not extruding
January 07, 2017 05:46AM
I have ordered a new metal extruder.
this is the picture of the hot end if still needed

Re: Filament not extruding
January 07, 2017 11:04AM
The heat barrier is way to long or not screwed up until it almost touches the drive gear / idler bearing
Attachments:
open | download - extruder _topless.jpg (330.8 KB)
Re: Filament not extruding
January 07, 2017 07:02PM
The M6 nut is not for locking the heater block from turning on the throat tube. It is intended to lock the throat tube from turning in the extruder body. The way you lock the heater block is to not quite screw the nozzle home in the block, screw the throat tube into the top of the block by hand (so you don't snap it) and hard up against the top of the nozzle. Then heat the extruder, hold the block from turning with a spanner and use a second spanner on the nozzle to tighten it hard. This then locks the nozzle and throat tube in the heater block and ensures a good seal that can't leak filament. When positioned correctly with the M6 nut up under the extruder support bracket there should be no more than two nuts thickness between the bottom of the nut and the top of the heater block. But also check that there is clearance between the top of the throat tube and the extruder drive gear.

Once you have tightened it this way you will need to heat the extruder and hold the block with a spanner before unlocking the nozzle to dismantle or change.
Re: Filament not extruding
January 08, 2017 09:04PM
this is how it came and was working fine previously.

I have now done it how I think was said however it doesn't seem to have fixed anything.

Re: Filament not extruding
January 09, 2017 03:47AM
You haven't checked my picture? The screw has to go further up, until it almost touches the gears.


Re: Filament not extruding
January 09, 2017 04:58AM
Legoset0,

I couldn't see the top nut in your original picture, hence my comment. Nonetheless the bottom one is not strictly required and shouldn't be tightened down hard against the block as this can stress and snap the throat tube. O Lampe is right when he says that the throat tube should sit higher in the extruder block. This makes it easier to load the filament and provides better filament support when printing with flexible filaments.
Re: Filament not extruding
January 09, 2017 05:05AM
I didn't notice the picture before however in my extruder it can't go up that far. I should be able to do it correctly when the new one arrives.
Re: Filament not extruding
February 24, 2017 01:26AM
I received the parts a few weeks ago and installed them, I haven't had much time however the problem seems to be fixed but now there is another problem, the prints look like this.

Re: Filament not extruding
February 27, 2017 05:30PM
what happened to me was nozzle clog, and then the nozzle got rekt so hard like yours it just couldn't extrude. get another nozzle. turn your flow down, i print on 97-98% standard, after slic3r slices the stl, the thingies on the side go away.

your print looks like that because your flow is higher around the bottom. duh.keep it the same. i keep mine on 97-98, again.

Edited 1 time(s). Last edit at 02/27/2017 05:35PM by Hedgehog.
Re: Filament not extruding
March 01, 2017 05:20AM
Sorry hedgehog flow down is not the solution.

wider bottom layers could be heatbed to hot - have a look at the "pictorial print issue identifier" thread at this Forum.
Re: Filament not extruding
March 01, 2017 05:31AM
It wont be the nozzle as I also replaced that, which might have caused part of it as before it was a 0.3mm nozzle and I replaced it with a 0.4mm one as it is what I thought I had. the problem at the bottom most likely is the temperature, I can change that but the other problem will still exist. could it be something to do with the extrusion rate since the nozzle size was changed. I was trying to print an item that has thin square towers and they ended up with rounded corners, it was almost a circle.
Re: Filament not extruding
March 01, 2017 06:22AM
Are you printing PLA?
If yes, how big was this object to be printed?
If it is very small, this is a very common problem - you might have to
-) go down slightly with hotend-temperature and/or
-) print more parts at the same time to let them cool down sufficiently and/or
-) need a layer cooling fan


Owner of a Sintron Kossel Delta Printer an a self sourced KosselXXL
Re: Filament not extruding
March 02, 2017 03:44AM
I lowered the temperature and it seems to have improved it a lot however the towers are still bad and the print has lots of stringing.



Re: Filament not extruding
March 02, 2017 06:32AM
your towers will automatically get looking better, if you fight the blobs and stringing.

fighting thees blobs and stringing is a thing of
-) retraction lenght
-) retraction Speed
-) retraction acceleration
-) travel Speed

-) travel Speed should go up
-) Keep retraction length short 2mm max (because you have a direct drive) - the less the better! - but not Zero.
-) do not accelerate to fast - else the molten Filament gets detached from the not molten one, and so dripping out.
-) do not retract to fast - same as above, but don't do it to slow - it's a bit of try and error

in your slicer: do you have the Checkbox "outer Perimeters first" (or similar) checked - if yes uncheck it
additionally do more than one Perimeter. If doing so, any lost blob will be missing on the inner Perimeter, and thus not visible from the outside.

Which tempreature are you printing at? - Maybe still to high.
Try to print with lower temperature - do it in 5° steps down, till the surface starts to look dull / Extruder starts skipping.
Then get temperature up a Little bit again. - You should have found a sweet spot, where good printing and layer adhesion combine with less dripping when doing travel moves.


EDIT: And looking on your top layer seems to me, you have a bit of overextrusion, Have you calibrated your E-steps?
EDIT 2: And/Or have you measured the Diameter of your Filament exactly and told your slicer this value?
Re-reading your Posts: changed Nozzle 0,3/0,4mm - you have to tell this your slicer too!

Edited 2 time(s). Last edit at 03/02/2017 06:41AM by Dancer.
Re: Filament not extruding
March 03, 2017 05:08AM
I have the temperature at 190, when it was lower I would sometimes get skipping. I have tried to calibrate the e steps however I am actually currently extruding 95mm instead of 100mm so this is probably not the problem. I have the nozzle set at 0.4mm in both places, I now changed the filament diameter to 1.9mm but am not sure exactly as I don't have digital calipers. I also lowered the retraction from 2 to 1 and increased the travel speed. the print seems to be a bit better but still not right.


Re: Filament not extruding
March 03, 2017 06:34AM
Ok - I think you should start with a 10mm calibration cube - uses much less Filament & is much faster to print.

If you manage to print one cube successfully, add a second one to get travel & retraction dialed in.

Just some things to check Prior to printing:
-) are all screws fastened?
-) are all belts fastened?
-) is your Frame rigid?
-) What is your print Speed? - For first tests to start: 30mm/sec, Layer 0,2mm with Nozzle 0,4mm; You can go faster, if you manage to do it good with this Settings.

I think I printed about 300 calibration cubes till now eye rolling smiley
Re: Filament not extruding
March 04, 2017 03:23AM
I have changed some settings and managed to get the 10mm cubes to look like these. I think the second one is the best and closest. I couldn't find anything to do with the frame or belts that could be affecting it. I have changed the filament diameter to 1.9mm, the layer height to 0.2mm and the print speed to 30mm/s. the temperature is at 190, raising it made it worse. I also tried lowering the filament diameter to 1.8 and that was also worse. Could it help to get a 0.3mm nozzle or try the old one as I don't know why I would have so many problems from changing the extruder.

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