Powder on Extruder Gears


I just purchased a TAZ4, and have printed a few (6 now) items with it in PLA. My first print was Thursday night (three days ago). I’m using the Silver PLA purchased through the Lulzbot website.

Today, I printed a 6cm tall squirrel (my tallest print yet), and a couple times it sounded a little rattly. I let it finish the print, and a couple of the supports (columns) looked a but unravelled, and one side of the model was rather rough. I’m afraid to print now, though, because the extruder gears are covered in a grey plastic powder. The gears are black, so I don’t know where the powder’s coming from. I went through the setup in the manual when I first started printing, and haven’t changed the filament since.

On closer inspection, the plastic flakes may be black. A couple flakes were big enough to see that, while the rest is a rather fine powder. It’s almost as if the gears are disintegrating.

Is this a common thing, and does it have a known resolution?

It’s possible that the gears are wearing down abnormally, but unlikely. You may see a bit of powder from time to time after a few dozen prints or so, but they generally don’t wear fast. What is more likely is that the filliament is grinding inside the idler chamber, and the residue is getting on to the gear surfaces. Check your idler arm tension, and see if there is any sign of gouging or scalloping out of the filliament that is in the machine itself at the moment.

Thank you for your response!

However, the plastic powder appears to be of black plastic (based on some larger flakes I found), while the filament is silver. So it seems that it’s not likely to be the filament.

I have slightly reduced the idler tension just in case, though. I’ll try a simple print of a small part later today to test.

Ok, I created a simple 20mm cup with 3mm walls, and it appears to be printing just fine.

However, in doing this, my first attempt at printing it made the whole printer sound like it was trying to force itself to do something it didn’t want to. It made a lot of noise and didn’t move. I turned it off, turned it back on, connected Pronterface again, and tried again, and it seems to be quite happy.

My extrusion fan was a little rattly though. I think that’s what I heard earlier that concerned me.

So, at this point, it appears to be doing fine, and isn’t producing powder. I’ll keep an eye on it.

Mine had the same kind of powder and after a couple months, my small herringbone gear split in half. Luckily, I was able to print a replacement gear with the broken one. I recommend printing a replacement large and small herringbone to everyone who hasn’t already done so. If those break, production is halted until you get one delivered.

Definitely print backups! And don’t forget to scale it 1% due to ABS cooldown shrinkage
It helps the consistency of the material to enclose the printer somehow and avoid drafts. That way the prints become harder to break

I just got a Taz a couple weeks back and my extruder is covered in grey powder as well. Upon inspection I noticed that the small extruder gear is broken. I will print another.

I suppose I should follow up on my own thread!

I have, as yet, done nothing in regards to this issue, but my small herringbone gear has split in half. It’s still printing delightfully, though. I keep meaning to replace it with a gear that Lulzbot sent me when I first posted this issue, but I appear to be rather lazy about it, as it still works.

Once I do, though, I’ll print a copy of it (perhaps in orange!).

Wow. Ok, so I am casually perusing the forum and come across this gem of a post. I have been learning and printing for the few weeks I have had my Taz 4, 2 dad blasted weeks before the Taz 5, and I too see the powder on mine… have for some time. I just ordered the Taz Mini, arrives tomorrow and I am a bit nervous. Do these things break like this with such regular frequency and limited time that replacement parts, gears actually, need to be on hand?

I would definitely print, and have on hand replacement small herringbone gears.

We had one break in half as well. Saw the dust before it broke.

Print them. It’s better to have and never need than to need and not have.

Well my mini just came in today… Part yay…part whaaa. I will take a look at the extruder of the TAZ 4 and see if I should be worried before popping open the Mini. Work too hard to have two printers that could be broken like that. Although I wish I did, I do not share the technical expertise nor time to build and constantly repair. I have recently had an issue where the larger gear kept slipping and “popping” back a few notches… This was on a new Flexi Dually, perhaps that is the problem. We will soon see.

I will say, I rarely come across a company as dedicated to service as Aleph Objects/Lulzbot. My guess is I am over reacting. Still I will take a peek and go from there.

Thanks for your response by the way.


if the large gear is slipping, it can only be a few things.

  1. Is the hobbed bolt loose enough that the bolt head has popped out of it’s socket on the large gear? if so, tighten the hobbed bolt.

  2. is the hobbed bolt socket on the large gear stripped out allowing rotation of the gear when it shouldn’t be? if so, you will need a replacement gear.

  3. check that the motor mount and small gear are close enough to the large gear that the teath mesh well

  4. Check the set screw on the small gear to see if it is locked down and tight. This can show up as the large gear not moving correctly, but it’s actually due to the small gear spinning on the motor shaft.

So I looked closely and did not see anything damaged, so that is good. What I did notice is little ribs on the PLA when I removed it. Almost as if it was grinding instead of pushing through the extruder. I suspect that has to do with the spring, but not sure what direction to go, in or out.