Filament getting stuck after 5-6 minutes of printing

Discussion in 'Calibration, Help, and Troubleshooting' started by Drip, May 15, 2016.

  1. Drip

    Drip Member

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    Hi all,
    My filament is getting stuck in the extruder after about 5 - 10 minutes of printing. The only way to undo it is to heat the head up, and then pull it out with a bit of effort. Then cut the front section of. It's then good to go for about 5 minutes of printing.

    So why is it getting stuck, I have tried temps from 190 - 225. After it's got stuck I'm not able to push the filament trough so it does not seem like it's a feeder issue.

    Any help will be appreciated.

    thanks

    J
     
  2. Sarah Nicholson

    Sarah Nicholson Well-Known Member

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    I would check that the heatsink fan is working and that the heatsink is staying reasonably cool. This could be caused by too much heat creeping up and making the filament swell. Having a good look at the filament you've pulled out can help to see if there's any bulges in it. Another cause can be too much retraction if you're pulling hot filament back past the heatbreak.
     
  3. Henry feldman

    Henry feldman Well-Known Member

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    Have you calibrated your e-steps?
     
  4. Old_Tafr

    Old_Tafr Well-Known Member

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  5. TimV

    TimV Well-Known Member

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    Reduce your retraction, if you have a direct drive (not bowden) to something in the range of 0,6mm. Had the same issue
     
  6. Drip

    Drip Member

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    Thanks all,
    I'll try this tonight, I did do this.

    Cleared and re inserted the filament, extruded a 100mm and it ran through smoothly! took a break for 60 second and extruded 100mm again, every now and again the gear slipped as it pushed the filament through, 60 second break again and still the same. I also noticed that when it starts the filament curls to the side, apparently this could happen due a partially blocked drive line if I can call it that... So I've run it up to 160 degrees and ran some more filament through, ran smoothly, will check and do all you your suggestions and report back
     
  7. Drip

    Drip Member

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    Hi all,
    So i've dropped the temp down to 190 and still the same issue, it seems like it mostly happens when it's filling in bigger flat surfaces as would be the case with the 1st and 2nd layers. attached is tonight's DSCN1338.JPG DSCN1342.JPG results. not the best...
     
  8. Sarah Nicholson

    Sarah Nicholson Well-Known Member

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    That looks pretty funky!

    You seem to have quite a few problems going on there. The bottom layer seems to have warped and lifted in places, so first thing would be to make sure your bed is trammed and maybe reduce the nozzle to bed difference a bit.

    What slicing parameters are you using, in particular infill %, number of perimeter shells and number of top and bottom solid layers?

    I assume you're printing in PLA, what's the bed temperature set to and what about cooling fans? Bits of that print look too hot, particularly the top few cubes, but that could just be not enough cooling on the small parts of the print or minimum layer time set too low.

    I would start by trying to get an accurately sized solid cube which will give you an idea of whether your extrusion rate is in the right ballpark or not. Try a 20mm cube with 100% infill, 2 perimeters and 4 top/bottom solid layers, tune your extrusion rate until it comes out with the correct dimensions. You can then try different temperatures to get a good surface finish.

    Of course this all assumes you're not suffering blockage problems. If you are, definitely try to pull some cool filament back out and have a look at the shape, this will help point to where the problem might lie. It could be a partial nozzle blockage or filament swelling in the PTFE. Another culprit can be if the PTFE isn't inserted all the way down which can allow a plug of filament to form.
     
  9. Old_Tafr

    Old_Tafr Well-Known Member

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    When I first built my printer and I had to cut the ptfe tube to go inside the hotend, I cut it with side cutters not a saw. (very sharp blade is best) This resulted in the tube being slightly squashed at one end. It also had a serious bend in it presumably from the roll it was stored on.

    In addition where it was cut (at both ends) it was uneven i.e. cut at an angle.

    No one of these things may be a problem, but for example if the end cut on a slight slope was upward then there would be a point where the filament could snag, or at the lower end possibly where a small amount of melted plastic would stick (and then possibly harden stuck to the filament preventing the filament from moving

    I cut the end at a perfect 90o, I ran a piece of filament through to check it was clear and where it wasn't ran a drill bit through to clear the inside. At the upper end I used a larger drill bit to very slightly countersink the end so that when filament hit it, it was guided inside. I also bent the piece of ptfe straight before fitting it.

    I can't say that any one of these things made a lot of difference but having things clean, clear, straight and made to guide the filament without gaps isn't a bad idea as once assembled it's impossible to know what is happening.

    Just looking at the ptfe supplied with my Titan upgrade, at one end it is cut flat and not distorted but at a serious angle, and the bend in it is quite pronounced. If this end was uppermost without tidying it up it could be a problem.
     
    #9 Old_Tafr, May 16, 2016
    Last edited: May 17, 2016
  10. Drip

    Drip Member

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    Thanks again for the advise will try them all one by one. Here is a pic of the fillament image.jpeg
     
  11. Sarah Nicholson

    Sarah Nicholson Well-Known Member

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    What is causing that narrow bit in the middle? That looks a bit suspect, when I pull filament from my hot end it's a single uniform cylinder until it tapers into the nozzle.

    It might be worth taking your PTFE tube out and making absolutely sure it's fitted correctly and seated right down into the heatbreak - Old Tafr's post above has some really helpful hints for getting it to fit perfectly. Also make sure you've put the thermal paste on the heatbreak threads and that the heatsink is being sufficiently cooled - the fins should be cool enough to touch.

    Also when reassembling make sure you have hot-tightened the heatbreak into the heater block.
     
  12. Old_Tafr

    Old_Tafr Well-Known Member

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    And also you have done the heat to (285oC I think) temp and tighten the nozzle. This is awkward and best done with a fixed size spanner or at worst an adjustable spanner not pliers or pipe grips which required a lot of force to hold the Al heater block and cause disaster if you slip. Use a box (socket) spanner for positive grip on the nozzle itself.
     
    #12 Old_Tafr, May 17, 2016
    Last edited: May 23, 2016
  13. Miasmictruth

    Miasmictruth Well-Known Member

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    I haven't read every post as I am tight on time so sorry if this was mentioned, did you apply the thermal paste to the heat break?
     
  14. Drip

    Drip Member

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    Hi all,

    So I've done most of the above, stripped it all down and rebuilt including thermal past and all, There was a little bit of play in the ptf tubing. Still the trouble continues. Watching closely it seems like the extruder stepper motor gear flicks back when it it suppose to move forward, this happens during normal printing as well as in mid air (to ensure no pressure). So it looks like it's the stepper motor where the issue is, I'n not sure what the root cause would be for this.
     
  15. Old_Tafr

    Old_Tafr Well-Known Member

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    If you can still extrude 100 mm without a problem but printing still brings up the problem and you are happy that the whole hotend is assembled correctly then maybe some basic steps to prove that you can control the stepper motor that drives the filament, then a look at each situation, 100 mm calibration and then printing.

    OctoPrint gives you the controls to move the bed, the steppers etc. and a choice of the size of steps. Maybe with the nozzle up to temperature from the front panel, a test of just extruding filament and quite a lot to see if it works continuously.

    If that works then the 100 mm calibration, then if this works, then a simple print with known slicer parameters, keeping things as simple as possible with default s3d settings

    -----------------------------

    Another option would be to make a video of your assembling the whole assembly, nozzle, heater block, heat break and heat sink. The thought here is that we all tend to make the same mistake at a certain point even though we think we are following instructions to the letter. We all interpret the same text differently.

    -----------------------------

    Just re-read the "motor flips back" bit .............. is this just the normal retraction (of which I know nothing ! ) but seems to be to stop filament oozing out when you move from one part of a print to another (etc.) ...............where you sometimes get a faint stringing effect.

    I still think some basic tests extruding a lot of filament via Octoprint would help to prove (or not) that it's possible to move filament steadily through the whole assembly.

    (really daft suggestion but the filament isn't getting stuck on the reel? I sometimes hear a real twang as it gets stuck and pulls free, so I pull a little off the reel now and again to make sure it's free. )

    Some check of removing filament to see what it looks like as suggested by Sarah would be good if things stop working on this simple extrude test.
     
  16. Old_Tafr

    Old_Tafr Well-Known Member

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    Different approach.

    100 mm calibration takes only a few seconds.

    Problem when printing occurs after five or six minutes.

    Maybe it is not related to the hot end or slicer parameters but to the extruder motor and the time?

    Did you set the stepper motor voltages (correctly)?

    If the motor was not quite receiving the correct voltage then it can give very odd problems.......... there is another post where there were millions of checks and in the end the voltages were out, when corrected accurately to the 0.55 to 0.6v (digital meter preferred)

    http://wiki.e3d-online.com/wiki/BigBox_Printer_main_assemblies:_Step_By_Step_Assembly_Process

    search on 0.55

    This post

    http://forum.e3d-online.com/index.p...-while-printing-solved.1264/page-3#post-12409
     
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  17. Drip

    Drip Member

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    Hi all, So many thanks for all the comment and suggestions, they have all helped me so far and I have learned heaps, Great stuff TOP Forum.

    I've increased the power to the stepper motor by means of turning the screw on the driver unit about half a turn and this has made a huge difference, and is in line with the comments from mike01hu above. I'll read the links he sent. Just printing the test cube now and will post a pic, it's still how can I say bouncing back now and again, about 90% less than before. so looks like this is the issue, just got to fine tune the stepper driver unit a bit more and hope nothing else comes up....
     
    mike01hu likes this.
  18. Old_Tafr

    Old_Tafr Well-Known Member

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    Set the voltages correctly :) too much voltage may be as bad or worse than too little.
     
    mike01hu likes this.
  19. Drip

    Drip Member

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    I've set the voltage to 0.6 of a volt, when I do a 100mm extraction it runs through just fine, when I loosen the pressure adjuster between the gear and the wheel that pushes or pulls the filament I get the following. Tighten it to much, constant kick back, loosen it to the point where it no longer kicks back then the filament does not feed enough.

    Could it be the filament that's causing the issue, I've had it now for about 5-6 months standing on my desk...?
     
  20. Old_Tafr

    Old_Tafr Well-Known Member

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    Some filament is hygroscopic, it's worth a check. No sure if like welding rods it can be "baked"
     

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