Difficulty unloading filament from Bondtech extruder  

RE: Difficulty unloading filament from Bondtech extruder

What exactly happens when you unload? I mean, when you took extruder apart (to free the filament), what did you see? Not enough filament extruded (filament remains between those two gears)? Or is there some blob at the end of filament, which prevents filament to come out between two gears in extruder?
Btw. I'm using same extruder for months and that never happened to me -just saying.

RE: Difficulty unloading filament from Bondtech extruder

Just pulled it out and there is indeed a blob at the end of the filament, stuck before reaching the gears on the side of the intake/filament sensor. I have had trouble pulling filament out before (both PLA and PETG), this is just the first time I had to take the extruder apart for it.

So why is the blob forming? Am I unloading filament too quickly after finishing a print or the other way around?

RE: Difficulty unloading filament from Bondtech extruder

So why is the blob forming? Am I unloading filament too quickly after finishing a print or the other way around?

No, blob can't/shouldn't happen by any user action (at unloading filament, in this case).

The problem is hotend. Or more precise: heatbreak.. or even more precise: because of heat, PTFE tube inside heatbreak became slightly shorter over the time (I assume that hotend is assembled properly, of course).
To spare you with explanations and to keep post short... Take hotend apart, check inside heatbreak (clean it if needed), check PTFE tube length and replace if necessary.

RE: Difficulty unloading filament from Bondtech extruder

That's the interesting thing. The hotend side is entirely new: new nozzle, heaterblock and heatbreak (brozzl - titanium). And yes, I made sure to push the block upwards while cold tightening but it is possible it slipped a bit when I hot tightened as I had to reposition it a bit.

And the blob happened with the previous setup as well (stock heatbreak) although for that one I assumed time had come to change the ptfe tube and decided to simply replace the heatbreak.

As for the blob as you can see it is not massive, just a slighlty enlarged bulb of material.

RE: Difficulty unloading filament from Bondtech extruder

Blob happens in heatbreak and the reason is (usually) gap between heatbreak and PTFE tube at the bottom. Brozzl doesn't specify the length of PTFE tube, so what length did you use? Brozzl heatbreak seems to be a Bondtech clone, so I assume it should be 36mm (with chamfer on both sides)

Anyway, your blob doesn't look that big and I would think it should pass trough extruder gears. Maybe you should reduce filament tension, so gears would increase gap easier to let blob trough.

RE:

I'm having a similar issue when loading and unloading filament with the Bondtech IFS extruder.  The extruder motor makes a high pitch noise and the gear freezes up when it tries to move more quickly.  But when it's going slow during the initial load or unload, it's fine.  It also prints just fine.  But it'll take several iterations to get the filament loaded or unloaded.  Not sure if these issues are related.  See the video linked here that shows the gear's behavior.  The door is open for viewing purposes, but the same thing happens with the door closed.

Note: I switched back to the stock Prusa extruder and the filament loaded/unloaded without issue.  Also, I tried to pass more current to the extruder as suggested by Bondtech support, but that didn't help either.

Any insight is appreciated.  Thank you.

RE: Difficulty unloading filament from Bondtech extruder

Can’t really help you there, managed to solve the unloading issue with mine after reseating the hotend (I assume).

RE: Difficulty unloading filament from Bondtech extruder

Posted by: @justinline

I'm having a similar issue when loading and unloading filament with the Bondtech IFS extruder.  The extruder motor makes a high pitch noise and the gear freezes up when it tries to move more quickly.  But when it's going slow during the initial load or unload, it's fine.  It also prints just fine.  But it'll take several iterations to get the filament loaded or unloaded.  Not sure if these issues are related.  See the video linked here that shows the gear's behavior.  .[.....]Also, I tried to pass more current to the extruder as suggested by Bondtech support, but that didn't help either.

Any insight is appreciated.  Thank you.

I am also having the exact same issue with my Bondtech. Such a maddening issue.

RE: Difficulty unloading filament from Bondtech extruder

I’m having this same problem. Any new solutions?

RE: Difficulty unloading filament from Bondtech extruder

Posted by: @fatato

I’m having this same problem. Any new solutions?

I also have this problem, I took it apart and put it back together several times to see what the problem was. But no errors found, it prints wonderfully. Nobody seems to have a solution to the problem. The steps etc are set. I have to load and unload the filament several times until it gets to the extruder.

RE: Difficulty unloading filament from Bondtech extruder

I guess i will chime in as well, just installed the ifs extruder, loading filament seems to go fine, but unloading is a hot mess. It takes 2-3 'unloads' along with some forceful tugging of the filament to get it out. Also the extruder makes some squeak sounds. Maybe i will try loosening up the tension as someone mentioned but initial impressions are not quite solidified as to whether this is an 'upgrade' or not

RE: Difficulty unloading filament from Bondtech extruder

Also same for me, Load and Unloading of filament isnt right.. 
Is there a way to increase load distance? I have to hit more 3 times after the loading sequence has completed. this wasnt the case with 4.1 firmware
Unload also seems to hang on to about 10cm of filament 

RE:

I disassembled and reassembled the extruder several times and the problem persisted.I have now replaced and tested bearings, screws and gears (newly ordered ones) and the problem still persists.After a few tries I got closer and was finally able to solve it.

Problem 1. is that the main shaft is under too much tension and, with tolerances in the mm range, the left inner bearing is crushed, which in turn means that the extruder wheels that feed the filament run together at the back and build up so much tension that the motor can't handle it to drive below this speed..Pay attention to the correct alignment (motor pinion -> drive pinion extruder)

The main reasons for this are the 3 screws for the housing halves and the 2 screws for fastening to Z.

I also put a small washer on the idler to reduce the movement back and forth. A 2 washer would have made the shaft too stiff. There is simply too much play compared to my other extruders. Of all the 6 extruders I own, none of them have as much play as this one.

Finally I managed to fix the problem (at least it disappeared for me) I loaded and unloaded the filament several times, even during printing (color change) it hasn't reoccurred since the changes mentioned, not once.

Changes:small washer on the idlerJust tighten the 3 screws that hold the 2 housing halves together very slightly so that the shaft doesn't tilt. Light means really light, only subject to minimal tension.Tighten the 2 fasteners to Z Minimum.2x filament conveyors and 1x main drive give some lubrication to the gears.

To properly adjust the tension of the filament feed, load the filament -> then unscrew the tension screw completely and turn it in until you feel resistance, that's enough.

RE: Difficulty unloading filament from Bondtech extruder