Dodgy stepper? I have been having heaps of problems with the extruder stripping the

3D Printing
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1

Dodgy stepper?

I have been having heaps of problems with the extruder stripping the filament and ruining the print. I have tried pretty much everything so far; temperature, pressure on the extruder gear, nozzle sizes, different hot ends and speeds.

Now I have noticed that when I push in new filament the motor locks up at a certain spot in its rotation. It still seems to work when under power though.

But I’m not sure how this can cause the gear to strip the filament.

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Try a different brand of filament and see what that does.

3

Of course try different filament but because your extruder motor “locks up at a certain spot in its rotation” when you push filament through by hand (hopefully with the motor disengaged), let’s diagnose that:

[NOTE: These are NOT novice troubleshooting steps. Please know what you’re doing and ask questions. I’m not responsible for you making a bad-situation worse. For example, Step #4 should be run without filament in your extruder. If you don’t automatically realize that, don’t run these steps]

  1. What type of extruder are you using?
    1a. Describe your filament management system… Where do you hang your roll? How many anchors does filament pass through before reaching the extruder? Is it running too tight for your extruder to pull?
  2. Have you tried loosening the extruder idler (if applicable) so that the filament slides freely then pressing the filament into the heated hotend by hand? What were those results? Smooth extrusion?
    2a. If the two-finger extrusion above is smooth and acceptable, perhaps you’re running with your idler too tight. Try slightly less tight than before and print again.
  3. Have you tried turning the extruder motor by-hand without ANY POWER WHATSOEVER being applied to it? Did it still lock-up in that certain spot?
  4. Have you tried swapping your E Motor connection with either your X or Y Motor connection (Not Your Z Motor connection) and issuing appropriate X or Y movement commands? Does the extruder motor run smoothly?

This isn’t an all-inclusive check list but it’s enough to get anyone started with extruder issues. Steps #2 might not apply to you since you’ve tried different hotends with the same results.

4

@Woody_Williams
Many thanks for taking the time with that response.

I have tried sever different types and brands of filament. PLA seems to be the most reliable at the moment. I can print with Arnitel the most reliably and ABS is fine to (which is pretty odd that I can print the hard materials fine).

To answer your questions:

  1. I have a Felix 2 modified to use a E3D v5 direct drive hot end. It is a simple direct drive extruder with a this toothed gear on the motor with a spring loaded bearing applying tension.

  2. I have used various spring tensions and also used various springs. At the moment I have pretty good tension (I think) where the extruder can exert a good amount of force.

When the motor is NOT powered up, I can feed the filament through fine. the gear does make small indents in the filament, but there is not enough tension there to squash the filament out of shape.

  1. Yes, and I can push the filament through with acceptable force. The problem is that it starts out this way, but some way through the process something happens and the extruder is unable to physically push the filament through. It then digs into the filament and kind of gets bogged (as it has dug in there is no spring tension left and it has a big bump to get over).

When it has failed, a few times I have paused the print and tried to push the filament through by hand (I do this by pushing on the spring to remove tension). I have noticed that it is very hard or not possible to push through. The display is still reading that the extruder is up to temperature.

Remember that I have tried two different hot ends (two different Felix hot ends) and now the E3D v5. I also moved from a 0.35 to a 0.40 nozzle. The 0.40 does seem a little more reliable.

  1. I actually had another close look at the problem of the motor turning and getting stuck. What happened there is that the top of the “cold end” must ahve moved a tiny amount and the grub screw holding the gear on was just touching it and jamming. I moved the gear along the shaft and that part is now fixed. I think, though, that this was a result of me re-assembling the whole extruder assembly a little wrong.

I did have a problem where the cold end was not lined up properly with the feeder hole and the filament was out of alignment. In fixing this I brought the cold end closer to the grub screw on the gear. This has been resolved.

But I don’t think my underlying problem has been resolved.

and if you have read all the way down to this point; THANKS. :slight_smile:

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I forgot to address question 1a):
I keep my filament in relatively sir tight boxes with 1KG of silica gel to keep them dry (have had problems before with humidity). I have a roller that I designed (http://www.thingiverse.com/thing:204244) that I sit the filament spool on. this goes from the floor to a simple guide that then feeds into the extruder. I run the filament through a foam cleaner that is just above the extruder. I have done several prints where I continually manually unroll the filament so that the extruder doesn’t have to pull the roll.