Extruder stops extruding mid print

Have bought a new prusa i3 and am having these issues like forever. The extuder does not print continously and stops extruding mid print, it starts again when i manually push in the filament and stops again after a while.
Also looks like it does not pull enough from the filament spool. Have leveled the bed, checked extrusion by extruding 10, 50, 100 mm of material, also tuned up stepper current.
Tried almost every solution on the forum, i feel like trashing my printer! Please help me.

Increase the tension on your extruder?

Filament spool turns easily?

No sharp turns in the path between spool and extruder?

Gear is tightly locked to the drive motor?

All screws tight?

Proper alignment of holes in extruder and hot-end?

I second what frankvdh said, make sure the idler tension is high and also try increasing the temperature to make the filament easier to extrude.

Yes, have tried it. I am printing PLA and have reached Upton 230 degs. Also there are no sharp turns between spool and extruder have used an idler support. The tension between idler and grab nut of my direct extruder is also max. Should i try using wades extruder?

Measure your filament diameter... it may be undersize.

Filament 'knotted' on the spool? I've had this where, when I set up the spool, I inadvertently pull the loose end *underneath* a second loop of filament. As the printer pulls filament, the second loop pulls tight and stops the filament from feeding.

230 degrees is very hot for PLA... I print at 180. Have you tried lower temperatures?

Print a smaller object for tests... I use a 10mm cube... only when that's good do I move onto something larger. This saves filament and time.

Mark the extruder gear with a felt pen so that you can easily see if it is turning or not. Also mark the filament with felt pen so that you can easily see if it is moving or not.

You need to watch your printer and try to recognise a pattern. Does it stop feeding when the nozzle changes direction? At the first layer? Never on the first layer? During infill? During solid fill? The layer after solid fill? Only after 30 minutes of printing? At a particular X or Y or Z axis location? When moving slowly? When moving fast? Once jammed, does it ever unjam itself? If you can identify a situation where it *always* jams up, then you're halfway to solving the problem.

Try to control the environment... no breezes or open windows or varying room temperature. The less uncontrolled variables, the easier it will be to solve. Change only ONE thing at a time. Different filament, or different temperature, or different feed rate.

Another thing to try is to "air print"... while printing, wind the Z axis up 10mm or so by hand, so that the nozzle is "printing" in midair. It obviously won't build anything, it'll just exude a long twisty thread. But this will at least tell you whether the problem is in any way related to the nozzle interacting with the bed or previously printed layers. If it doesn't jams up, the problem is in your nozzle or Z settings. If not, then the problem is elsewhere.

It may be a good idea to turn down the current to the extruder motor, so that instead of grinding away silently at the filament, there will be an audible click as it skips a step, so that you immediately know when something is going wrong.

Interesting that you mention filament size . . . I recently got a spool that had small sections that were over 2mm (on a 1,75mm spool) that would not physically go through by bowden tube.

- Tim

I cant thank you enough for taking so much time and effort to help me out. I will try those things and try varying one parameter at a time and get back. Also I have noticed a pattern though,
If i keep unspooling by hand so that there is some loose filament hanging above the extruder entrance, it prints fine. It prints small parts well. It screws up during long rapid strokes like solid infill and bottom layer infill. I thought higher the temperature easier will the material flow. At 180 it does not flow very fluid.

Before I abandoned my bowden system I noticed something that might be affecting you too.
Curled up filament, especially when reaching the last layers of a spool was very hard to get through the tube.
Although I tried teflon and normal blue air hoses (which actually worked better) I never got rid of the inconsistent prints.
And due to the high pressure required to push the filament through the hobbed bolt started to get clogged with filament dust relatively often.
Until the nex extruder was ready I partially counteracted the filament problem with a heat lamp (the infrared ones for personal use not the heaters for a terrarium).
Had the spool about 1m away from the printer and the light placed so the filament would warm up on the way to the printer.
The result was that the filament came to the extruder almost striaght instead of a curled up spring.

But I am not going back to a bowden system with this printer again.

Quote
siddhesh92
I cant thank you enough for taking so much time and effort to help me out. I will try those things and try varying one parameter at a time and get back. Also I have noticed a pattern though,
If i keep unspooling by hand so that there is some loose filament hanging above the extruder entrance, it prints fine. It prints small parts well. It screws up during long rapid strokes like solid infill and bottom layer infill. I thought higher the temperature easier will the material flow. At 180 it does not flow very fluid.

Higher temperature does ease the flow, but it also makes it more likely that the filament will soften too high up the hot end if the hot end heatsink is not being cooled enough, or the hot end has a PTFE liner that isn't a good fit.

195C is a good temperature to start printing PLA at. When you have solved your extrusion problems, if you have a problem with stringing then reduce the temperature from there.

Both my printers use Bowden extruders, and I find them reliable.

Edited 1 time(s). Last edit at 07/29/2015 10:52AM by dc42.

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

Quote
siddhesh92
If i keep unspooling by hand so that there is some loose filament hanging above the extruder entrance, it prints fine.

This sounds like friction somewhere in the filament feed. Can you post a photo of the whole printer?

I will, I am out for a meeting, will post my pictures along with all the situations once I get home on Sunday. Thank you for your help.

Here are pictures of my setup, please help me fix this mess.

The location of your 'idler support' pulley means that there are quite tight bends in the filament path, particularly when the head is further to the right.It also means that as the head moves left-to-right, it pushes filament back towards the spool (which could cause 'knotting' of the filament at the spool), and as it moves right-to-left it will pull it from the spool (if there's friction this may cause variations in feed rate). In a few months, this may also cause wear in the extruder, which will cause more jams.


I suggest mounting the spool *above* the printer somehow, so that the filament feeds more-or-less vertically straight down into the extruder, and get rid of the pulley. After many jamming issues, I currently have my spool holder on a portable workbench on top of the printer table, until I can get something better built. Maybe mount your spool holder on the side or back wall of your alcove? If you don't want to do that, you should get some improvement if you lift the spool up higher where it is now; just replace the short vertical bits of PVC tube on your spool holder with long bits. Also, turn the spool over so it feeds from the top instead of the bottom, to get a straighter feed path. Keep the pulley I guess, but put it halfway? between the head and spool to minimize the angle.