Details:
v1.3
~1500 hours before issue
horizontal
Barrel wrapped 90% with fiberglass pipe insulation after about 1200 hours of use
187C
MG94, had been open to humid atmosphere several weeks
Typically 18-22"/min @1.75mm with a melt filter nozzle
Slowed to a near stop over 5 feet (which took 20 minutes or so)
Nozzle was fine
Tweezed out plastic up to auger tip, ran machine with nozzle off. Auger would not feed. Let cool to ambient, could turn auger in barrel with wrench (~10Nm of force required)

How I fixed it
Remove hotend (barrel+auger+pipe coupling+heater) from Filastruder
Let heat to about 200C
Using a large clamp and steel rod, press out auger. Plug should come with the auger.
Reassemble

I wrestled with it for a while before figuring out the above. Other than heat up time, it only took about 5 minutes to fix.

Photos:

This is interesting, because it shows the length of the melt zone. With a fully insulated barrel, it looks like pellets begin to melt about 2" before the auger tip, or about 3" away from the nozzle face.

Barrel and auger seemed to be in pretty good shape for 1500 hours of use.

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You're supposed to be on vacation!

To extrude,  there needs to be friction between the barrel and pellets,  and less friction between the pellets and screw so the pellets will resist getting spun and get pushed forward instead.   I wonder if there is a way to lubricate the auger to discourage pellets from sticking to it.   Makerbot users found that they could keep PLA from  sticking and jamming by coating the feed tube with a tiny amount of canola oil.   I wonder if something similar would work here.

Teflon spray maybe? Canola oil at the least is a bad idea, it will spoil esp at elevated temps.

1) Let it cool to room temperature over several hours.
2) Disable auto-start on motor
3) Heat barrel to 175C and let it soak for an hour
4) Empty all pellets out of hopper area
5) Manually pull plastic goo out of the front with pliers
6) Run Nylon T6 pellets in the machine (175C is way too cold for these Nylon pellets!)
7) Continue to tweeze plastic goo until the dam breaks and all the Nylon pellets show up at the output
8) Attempt to extrude Nylon for shits and giggles
9) Let next batch of MG94 push out failed Nylon test

The Nylon pellets acted as a sort of abrasive to grind the plastic off the auger and walls of the pipe.  Now it extrudes fast enough to get 2RPM on my winder, which keeps up with extrusion.  I'm running 20"/min based on some crude math, and that's on an otherwise stock setup at 180C with a wrapped barrel and melt filter.

https://www.youtube.com/watch?v=qgVLU80 … e=youtu.be

However, I absolutely will take you up on that offer next time it jams.  Should be in 1kg or so, based on my track record

Tim,

I'd be willing to mail you my filastruder if you'd like to dissect it and see where the flaw lies, especially if it's come up before.

I'd be open to this, but it seems a bit wasteful to send the whole 'struder - expensive, and it means you can't 'strude while I'm troubleshooting. I'd propose instead:

I send you a 1.75mm barrel/pipe coupling/auger/thrust bearing/bushing/spacer set/hex socket

You send me what you take off your machine, and I can troubleshoot it when I have time without holding you up.

If you want to do that, shoot me an email through the contact form. I'll pay shipping both ways and for the parts themselves.

One thing to do in the meantime - turn the machine upside down so pellets fall out of the hopper, then take a photo down the hopper. I'm curious if pellets are getting stuck to the screw that far up due to the increased temperature (185C vs. 180C) and full wrap all the way to the hopper.

I've found that the thing that seems most likely to trigger the problem is higher temperatures -- you might try extruding at 180 instead of 185 -- and that insulating the barrel (which you say you've already done) does make a huge difference. I recently re-wrapped my whole barrel and that seems to have mitigated the problem. I haven't seen the problem crop up since I did that, after seeing another post on this board.

One possibility -- the picture above shows your insulation right up to the nozzle, but the nozzle is already removed -- how much insulation have you left right over the nozzle itself when you're running the filastruder? The instructions say that the edge of the insulation should be even with the face of the nozzle. I think that's because if the nozzle, where the thermocouple is measuring temperatures, is not insulated, then the temperature being read will be significantly lower than in the melt zone, which may mean that the melt zone is over-heating causing problems.

I'd be willing to mail you my filastruder if you'd like to dissect it and see where the flaw lies, especially if it's come up before.

What seems to happen is the plastic cakes on the flutes of the auger, and a separate layer cakes on the inside of the barrel.  There's a small gap between the two (visible in the 1st picture -- maybe 1mm?), and the molten plastic there just smears around and never moves forward.  And, yeah, the first pound was flying.

I too thought a long melt zone would be beneficial, but after seeing the machine in action, I'm more in favor of as short of melt zone as possible. I think the longer melt zone puts more strain on the motor, especially during start up.  I now just have some aluminum muffler rap, one layer on the nipple and the usual fiberglass around the heating band.  If I'm printing in a drafty area I'll wrap tin foil around the lower half just to keep airflow down to reduce variables.

If the colors being used are getting dispersed (and I've used dry pigment), is there any advantage to using a long melt zone?

Honestly, this issue has come up a couple times with other folks, but never for me personally so its hard to troubleshoot. Twice it was with GITD master batch, and one or two times it was pure MG94. Since I haven't seen it personally, it's hard to contribute much experience. I would probably say to get a brand new barrel/auger - it'd have to be a v1.5, so that'd be barrel/auger/thrust bearing/spacer/hex socket. Email me if that's something you want to pursue, other than that all I have are guesses relating to the heat wrap (I don't use wrap, I just put another piece of fiberglass insulation on mine and the first inch between the barrel and insulation is open) or the auger position relative to the barrel axially.

Also, 1lb in 3 hours seems really fast. How many ipm was that? I'd guess approaching 30ipm at 1.75mm.

I print a lot of hoppers. About 70% of the Filastruder orders are with hopper.