Serious issue with extruder on pre-assembled core one makes it useless.
[Reposting this question since I've had no time to look at it recently and need to know how to fix it]
I bought a pre-assembled core one, and have printed successfully on it about 5 times (only with PLA).
A while ago it jammed while printing while I was out of the room.
I thought it was a nozzle, so I tried purging, un-loading, loading and cleaning, but nothing helped.
After extracting the nozzle, while I found filament in it, it wasn't the issue. The filament had broken off just above the top of the nozzle entry.
Looking into the gear assembly, I see (attached photo).
It looks like a bomb has gone off it there!
What on earth could have caused this? Is it repairable?
What I want to know is:
* What parts do I need to repair this (look at the photo to see the massive damage in the extruder)?
* Can I order a pre-assembled part to fit (I'm not the sort of person to build these things from scratch and don't have a 2nd printer - I bought the Core One for reliability and got nothing of the sort)?
RE: Serious issue with extruder on pre-assembled core one makes it useless.
I wouldn't call this "massive damage". It looks like maybe the top part of the main plate filament guide got chipped.
How old is the PLA you are printing? PLA can get brittle over time and can snap easily. Have you tried a different filament?
You best recourse to contact support over chat. If they determine the main plate is damaged, they will send you a new one.
RE: Serious issue with extruder on pre-assembled core one makes it useless.
For reference the part is here: https://www.prusa3d.com/product/extruder-main-plate/
RE:
I wouldn't call this "massive damage". It looks like maybe the top part of the main plate filament guide got chipped.
How old is the PLA you are printing? PLA can get brittle over time and can snap easily. Have you tried a different filament?
You best recourse to contact support over chat. If they determine the main plate is damaged, they will send you a new one.
The metal teeth appear to be heavily chewed up. Thanks for the name and link to the part though, that's helpful.
This was about my 5th or 6th print and the PLA was opened less than a week before and kept in a zip-lock with desiccant.
David
RE: Serious issue with extruder on pre-assembled core one makes it useless.
Ah OK, in that case I think a piece of metal somehow got between the gears and idler bogie pulleys. Filament on it's own would not do this. You will need to get the planetary gear box replaced then.
Most definitely you should get on webchat with support. They can guide you to what to do next. Perhaps send you the parts for free under warranty.
RE:
I've disassembled and cleaned around the teeth and head plate. A few things to note:
1. This is factory assembled and never opened by me.
2. The 3 bolts holding the gear cover on were so loose that they started turning as soon as I put the allen key in, before I applied any torque. The cover wasn't obviously moving, but there was no tension in the bolts at all.
3. Most of the damage was cosmetic, a lot of ground up filament, but a little damage to the teeth (but I assume these are only for gripping and pulling filament and don't have to engage with anything else). I am hoping it's going to work and avoid me needing to replace the whole gear assembly.
4. There was some small amount of ground up filament in with the planetary gears. I cleaned the metal teeth carefully with a small amount of IPA and re-applied lubricant from the small tube provided by Prusa (it had about the same viscosity and colour as what was there, so I've assumed it's okay to use there, *please* correct me if I'm wrong though and I can clean it out before I use it).
5. The head plate is (technical term) "knackered" though, and I don't have a 2nd printer or know anyone local who can print it, so I guess I'll be ordering that rather than printing it. At least it's $3.50 instead of hundreds though.
One thing I'd be interested in knowing is how to best test the filament that's been sitting out for ~6 months at this point (or do I just bin it)?
I've got a drier and have put it in for 45c for 4 hours, but I'm a bit worried this whole thing happened because the filament was more brittle/hard than expected (I had put it in the drier as a test when I got the drier and don't know if that can harden it). Does the printer have way to test this or is there a test with hand tools you can do? The filament bends without breaking, but that's not strictly a measure of "hardness" or ability to melt at the expected temperature.
And next I have to unblock the nozzle (I don't have a soldering iron with controllable temperature, so I might try the oven approach and a cold pull).
RE: Serious issue with extruder on pre-assembled core one makes it useless.
PLA can become brittle and crumble due to moisture if leaving it out in the open for 6 months or so. In dry storage it can last for years. Would be good though to pop in a dryer for 6-8 hrs.
Also make sure after you reassemble the planetary gears to run the gear box calibration wizard before attempting a print.