Considering its the weekend tomorrow, I suppose I have no choice but to undo some screws and tear this extruder head open to see what the gears are doing.
The logical side of my brain concurs with the notion that the gears are skipping because of one of three things:
Spool is snagging and preventing the filament from being pulled effectively by the gears, I verified the spool is free and everything rotates nicely, no extraordinary force required to pull the filament in.
The point where the filament passes through the nozzle, which requires no obstruction and proper heat to allow the molten plastic to pass through at the desired flow rate. Having swapped nozzles, I can at least eliminate that as the culprit.
The part in the middle, doing the grabbing and pushing of the filament strand itself which is the gears. This is the part that I am unable to visually inspect and must open to see for myself if/what is going on there.
I realized I have a brand new nozzle somewhere that I want to grab and test. But before I do that I want to check the gears first.
Alright, stepped out, came back with a fresh head. I think I found the culprit and I am going to throw this here for anyone that has gone through the same route I did just in case this bites you down the road.
First off the core issue. The 0.6mm nozzle I used is a hardened steel head that I used previously to print some PETG-CF. It seems that there’s a tiny amount of CF reside/shard/debris that is stuck in there in a way that allows filament to flow to a certain extent, but once the flow rate (aka the motor tries to stuff more material in) goes up, the gears are skipping as they simply cant push the filament through enough.
What did me in, is when I swapped nozzles, I swapped with another 0.4mm that was already having the same issue. The nozzle had clogged, but I was able to declogg it by heating it up and driving a 3.5mm needle through it. HOWEVER, this did not clean everything, there had to have been more gunk that was stuck to the walls of the inlet side that I simply couldnt clean and so when I went to drive regular PETG into it, which prints a lot faster than PETG-CF, the debris caused the same restriction and caused the gears to skip.
I dug through my box of stuff and found my old non-hardened 0.4mm head. I swapped to that and I am now 2 hours into a print that seems to be going as expected.
Moral of the story: If you are going to print abrasive stuff, like CF, or sparkly stuff, etc. I know the site says you can use 0.4mm, but please don’t. It will just clog up. As you can see even the 0.6mm clogged up. I wonder how the 0.8mm would fair. But if you’re going to do that, keep at least one nozzle for pure non-abrasive filament as that will guarantee that you at least won’t have random debris in there down the road.
I don’t know how much damage this has done to the gears, but I am going to order some as well as new hardened steel filaments. And I am hoping I can at least finish my two rolls of PETG-CF with a 0.8mm nozzle and never ordering them again.
I think that lot of issues with extruder not extruding on A1 is caused partly by a bad design of extruder gears. There are other factors of course, but generally the ability to extrude is worse on A1 then on P1/X1 because of the extruder gears design.
A1 extruder gears:
The left wheel is smooth, it just applies pressure to the right gear which feeds the filament and has a design of a mill wheel instead of classic teeth on P1/X1.
This doesn’t have to affect you if you print only regular PLA, but once you add some matte PLA to the mix or other slightly abbrasive material, you can have problems. Because of abrasives, filament hardness, melting point, etc.
This is the only reason I regret buying the A1 and I’m thinking about switch to P1.
