Simple Way to Fix Filament That Won't Unload

[Aaron]

I've had the MOD-t for a while now (October) and consistently I find the filament unload process is the one most prone to failure. Lately I've found a way to get it unloaded consistently where the carriage doesn't jam and grind the filament to a point where it's stuck. While I'm sure New Matter will NOT approve of this method, I've had very good success with it.

First, attempt a normal filament unload. This helps get filament out of the hot end. IF it doesn't work then go through the following steps:

1. Unplug the printer.
2. Wait for the hot end to cool off (10-mins).
3. Disconnect and unscrew the hot end. You will likely have nothing in there or whatever filament IS in there will slide out. Try to clear out whatever you may see in there. You will probably see a small piece of filament hanging from the bottom of the carriage. DON'T TOUCH IT!
4. Snip the incoming filament from the TOP of the carriage (where it feeds in) so it's no longer connected to the spool.
5. Connect the hot end clip to the carriage connector but do NOT screw it back into the carriage. Leave it hanging.
6. Plug the printer back in.
7. Run the filament LOAD process. Caution: the hot end WILL heat up. Be sure not to touch it! What happens here is instead of the printer trying to pull the filament up and out (which grinds the filament and likely causes a jam) it instead pushes forward which seems MUCH more reliable. 
8. Wait until the filament no longer moves downward. Use a pair of pliers to grab the filament from the bottom of the carriage and gently pull it down & out. Because no gears are holding it anymore, it should slide right out. If you have to use ANY force, it's still being gripped by the gears. Once pulled through if you look through the top of the carriage where the filament loads, you should be able to see all the way through to your build plate. A lamp nearby to give ample lighting does help. This means you're all clear!
9. Unplug the printer and wait for the hot end to cool.
10. Disconnect the hot end, screw it back onto the carriage, reconnect it.
11. Plug the printer back in.

Again this process won't stop a clogged hot end, which is why I always try to run a normal unload first. However when it fails (which it does most of the time) this process really comes in handy. It's helped me a ton and I hope it helps you guys out.

Good luck!

[Christopher Leger]

Makes sense. I like it.  Will definitely give it a try. Thanks.

chris

[Atrix]

this is how I will be changing mine, I have loads of issues with mine.

I would like to add between9 and 10.

• load the new filament into the printer head so it pokes out the bottom a little (trim as needed)
• while reattaching the hot end and guide the filament into the hot end so you don't damage the Teflon inner tube

[Jonathan Mayer]

I had this issue last night and came to start clearing my issue the same way.  I unscrewed the hot end, but I also cleaned this out with a solid piece of 22awg wire as well.  There was quite a bit of filament still in there and I figured this couldn't hurt.

My tangent aside, I had an issue where the worm gear would not move during load or unload.  I thought a motor had burned up, but after some searching I found a resolution on new matter's website (of all places).  Apparently the motors will not run if the z-axis is all the way up to the top.  I had to manually lower about an inch and re-run the unload process.  The gears worked and the filament was removed.

On Tuesday, January 19, 2016 at 1:14:00 PM UTC-5, Aaron wrote:

[AlanZ]

I was having difficulty with a filament change... the motor would not engage to move the filament.

Fortunately your post reminded me to lower the head about an inch, and I was able to get going again.

[Christopher Leger]

Well, it happened finally.  My house has been high humidity lately and I suspect that my filament is not as ideal as it was, so I got a jam.  This method worked perfectly!

Woot!  thanks again

On Tuesday, January 19, 2016 at 1:14:00 PM UTC-5, Aaron wrote:

[Greg L]

This was brilliant to allow me to clear a hot end jam ... while the hot end was plugged in and heated, I was able to pull the broken piece of filament out.

I'm still trying to get the filament out of the actual printer now. Tried load, and now trying unload. Not sure - I might be stuck. :(

[Jackson He]

Try to load (instead of unload), but with a new filament so that it'll push out the old. 

As a matter of fact, if you just use load with a new filament in the first place (after cutting the old one from the top of the carriage), you don't even need to ever unload or detach the hot end.

[Greg L]

On Wednesday, February 3, 2016 at 7:35:48 AM UTC-7, Jackson He wrote:

Try to load (instead of unload), but with a new filament so that it'll push out the old. 

As a matter of fact, if you just use load with a new filament in the first place (after cutting the old one from the top of the carriage), you don't even need to ever unload or detach the hot end.

My situation was such that a stub of the filament was hanging out of the top of the carriage. I think I was experiencing a hot-end jam as well as a feeder jam. I disconnected the hot-end and was actually able to remove the filament.

What I cannot seem to do is to get the carriage/feeder to pull new filament in to push whatever is jammed through. Argh.

[Christopher Leger]

That's where my jam was...Hot end had nothing to do with it. I cut off the top of the filament, and removed the hot end.

I was left with an inch out the bottom and an inch out the top.  I ran the load process and although the filament didn't move on its own, I gently pulled straight down with some pliers.  Gentle didn't work.  I had to pull hard, and I'm sure I risked breaking the gear or teeth, but it worked and suddenly started going through on its own.  Looking at the filament later, it looked like the teeth of the feeder dug a little divot into the filament and my pulling gave the feeder teeth a place to regrab the full diameter filament just above it.

Glad it worked, but I'm hoping to avoid having to do that again in the near future...

[Jason Unrein]

FWIW, I had a similar issue.  The print head crashed and I couldn't get the filament to move.  There was some black plastic from the base plate that was melted into the head but it would still let a small amount of filament through when trying to load new filament.  But after a while, nothing would come out.  Ultimately I followed the above steps to clear the printer:

1. Unplug/cool down the printer
2. Remove the hot end extruder
3. Verify the extruder is clean (mine was)
4. See if you can move the filament suck in the internal gears
5. Assuming so, make sure the extruder is plugged in but not screwed in
6. Clip the filament above the unit so you won't have to feed much through (I left ~5" in case i had to do something different)
   
7. Power on the unit and run it through a load cycle
8. While it is trying to push the filament through, grab the bottom and pull with a pliers.  As said above, it does take a bit of force.
9. Hopefully after a small bit of pulling it will move on its own. 
   
10. Once the filament is clear from the unit, power the unit off.  I put a light under the unit and verified I could see through the hole the filament goes through
11. Re-attach the extruder
12. Power the unit back on
13. Do a normal load filament process and it hopefully will work just fine
    

If anyone is interested, it was the problem where the gears gouged into the filament.  Pic if you're curious