TAZ 6 Extruder Mount Cracked and Broke

Just wanted to know if anyone else has had issues will the stock extruder on the TAZ 6 loading filament and finding it gets stuck where the extruder mount/guide meets the metal hotend (hope I used the right terminology). I didn’t think much of it and thought it was normal and you just needed to give it a little force to get it past that part. Well over time I noticed extrusion of filament got worse and inconsistent to the point it would not even feed.

Took the extruder assembly apart and found the 3D printed mount was cracked in two places where the bolts screwed into the aluminum plate. I took off the bolts and barley touched the ends on the mount and they fell off. I assumed the cause of the crack was due to the stress of pushing in the filament combined with the heating and cooling around the part.

I have ABS glued the parts back together and even have a new mount on order from itwork3d, shout out to Jamie and his store for always bending over backwards for his customers. I called his store since they didn’t currently carry the part and within hours he had it up on the site and I was able to get it ordered!

This brings up a few questions for me:

  1. Has anyone ran into this as well and if so have any idea what may have caused it?

  2. I would like to print a new mount in a different filament to avoid this from happening again do you think nylon would be the best fit?

  3. Any tips on making sure there is a smooth transition of the filament from the feeder portion into the metal hot end?

  1. Nope, overtightening the bolts possibly, possibly y axis nozzle drag without using a taller extruder modification, or just a bad layer in the print.

  2. polycarbonate would be ideal. Nylon might flex

  3. Leave a bit of fillament in the hotel and use that as an alignment pin.

Thanks piercet,

  1. over tightening is possible but I have never taken the assembly apart before but it is a refurbished model. That being said I am starting to think you had it right with bad layering in the print because when I could see inside, you could it had poor layer bonding and I could see the individual filament lines as they are laid out.

  2. Never used polycarbonate before I will take a look into using that first then.

  3. I feel dumb for not thinking of that my self its so simple its genius, thanks for the tip.

I let the ABS glue dry and sanded it down and assembled the extruder back together. I filament clears better now but it still has issues moving through the metal hotend itself when it is empty. I was hoping the issue was it scraping on the miss alignment between the plastic feeder and the metal hotend but it looks like there may be filament deposits or something catching on the filament in the hotend.

I tried extruding 300mm of filament a couple times and noticed the gears were grinding on the filament again and extrusion was uneven to almost non at times. I will need to find a way to clean it or replace it.

One last possible option is I am testing this on PLA that is at the end of the role and so it is in a very stiff coil pattern so maybe it is having a hard time strangling out as it goes through the feeder and hotend. Just a thought may need to test out filament on a larger role.

You may want to check out the reinforced taller extruder body. http://www.thingiverse.com/thing:1355145

I also have a reinforced extruder mount, but it works best for ABS printing, if you are printing mostly PLA you may want to stick with the stock mount design.

The hobbed bolt is essentially indestructible, and can be cleaned with a small pick, or a tiny flat head screwdriver. Open the idler chamber, then clean any residue you can see on the bolt, rotate it a bit more to get the rest, etc. It is not possible to have worn it out. You will want to check the state of the bearings. The Taz 6 used nice sealed bearings for the Idler and extruder 608zz bearings, so they shouldn’t be gummed up. You’ll want to make sure the idler bearing in particular still turns properly. Also check that the filament hole in the extruder body lines up with the deepest part of the hobbed bolt ground out notch. If it is offset, move the large 8mm washers around front to back until it lines, up, potentially adding or removing washers to get a good fit. I’ve found that adding a particularily thin 8mm washer to the front gear stack often helps get perfect alignment there.

You will also want to make sure the idler arm tension bolt springs are tight enough. They should have around 7mm distance between the washers on either side of the spring on both bolts. If the filament is still gouging out, tighten them a bit more. If you are still having issues after that, you may be experiencing a thermistor or heater core issue with your hotend and will want to check and verify the temperatures it is operating at. A partially failing thermistor will report that it has reached a higher temperature than the heater core is actually at, causing the printer to sometimes extrude plastic at lower temperatures than you have it set, which in turn puts more strain on the extruder and can lead to issues.

I have not in the past printed that much ABS on the TAZ 6 due to just not having that much luck getting it to print reliably as a whole and I have not run into a need for a strong print till now. But when I had the mini man it printed ABS like it was PLA with no issues but the TAZ must be a beast all its own in getting to work properly or at least the unit I got seems that way. I am going to probably try to print that part out since I do have plans on printing more materials like ABS going forward. I am just taking baby steps as I master this beast.

As for the getting the filament to feed correctly I was able to get it to work on a newer spool of ABS I had laying around with almost no issues at all. I am out of PLA as the spool I was testing on was my last one and I ditched the last few meters of it because of how tightly curled it was once you get to the end of the spool. After printing the ABS with little issue I am convinced it’s just the nature how stiff cheap PLA can be right at the end of a role. I was cleaning the groves in the hobbed bolt after each try but I didn’t check to see if the bolt was lined up with the feed hole so I will check on that.

I did check the extruder bearing that the filament rolls on as the hobbed bolt feeds the filament and it did seem a little still but was not sure if that is normal. I am used to bearings spinning freely if you put some force on them but this one does not seem to rotate unless you are directly applying force to it. Is that to be expected?

I have no way of checking temperature manually currently but have always wanted an excuse to buy one of those laser thermometer guns so now have one on order so I will also verify that as well.