I have been working to get my 3D Chameleon working for a few weeks now and have been able to work out all the issues exept one.
After 4-8 color changes a filament will fail to unload. Checking the filament there is a big notch where the chameleon gear grinded away at it.
I thought it was due to loading too far during load, so I tuned that so it doesn't grind the filament at all but feeds consistently still. Probably undershooting load time by a hair.
It kept happening so then I thought the filament must be getting stuck either in the extruder or PTFE opening. I checked the filament and it can easily pass through and is not trapped in the gears when this failure occurs. So I don't think it's a tip shape or unload issue.
I tried a few different slider tensions, but no difference was noticed for this issue. Currently using the default tension, +.25 spacing, for all of them.
It seems to happen sooner with some filaments than others.
My loads and unloads are perfect at this point, but I can't seem to figure this one out.
Any ideas why this might be happening and how to find the culprit?
Edit, more info: This is on my Creality K1 Max. I see the extruder lock arm move a bit (indicating the filament is in the gears) at the same time as hearing the motors stop, so I think my load time is spot on. I have been checking the filament after each unload to see if there is a spot gradually wearing down, but never notice anything. Then out of the blue it just happens. Perhaps when unloading? UPDATE: It seems that the default tip shaping was the issue. For whatever reason it was not consistent and occasionally gave a wide tip that got caught in the PTFE when unloading. I redid my tip-shaping code, and now it is both more conistent and faster.
G0 E-25 F2000 ; retract a bit, adjust this to tune waste
G0 X295 Y150 F4000 ; move to aux fan COOL DOWN
M106 S255 ; part fan 100%
M106 P2 S255 ; aux fan 100%
G0 24 F1500 ; TIP SHAPING WARM
G0 E-5 F500 ;
G0 E5 F1500 ;
G0 E-2 F500 ;
G0 E2 F1500 ;
G0 E-24 F500 ;
M106 S0 ; part fan off
M106 P2 S0 ; aux fan off
G0 X284 Y293 F4000 ; MOVE TO BUTTON
G0 E-60 F500 ; RETRACT
G91; relative mode