I'm pretty new to 3D printing, got my printer about 5 days ago and spent most of my time with it.
First off, it is an Ender 3 Pro with everything stock, haven't made any upgrades except I run it with OctoPrint from a Raspberry Pi Zero but I have determined that's not the source of the problem as it's well within 80 % idle on its CPU.
The issue I'm experiencing is that the extruder starts slipping at some point along the print. It's not the clicky type of slipping that appears to be the common issue but rather it's just spinning and grinding on the filament which is remaining stationary. When this happens the printer continues on about its business as it's unaware that filament is not coming out. I move the Z-axis up, squeeze the extruder lever and try to push on the filament which is not budging, which made me think I had a clogged nozzle. I was surprised as it's a brand new printer but the internet says that nozzles clog up so I disassembled and cleaned it just to find that it happens again on my very next print. I noticed that when I pull or push on the filament by hand while squeezing the extruder lever - relieving pressure from the gear, it is quite hard to do so, even partly impossible as my fingers start to slip, I have to squeeze extremely hard or use pliers. I pulled the filament out using quite a bit of force, then snapped off the piece that was already in the tubing and inserted fresh filament which slid very easily through the white tubing to the hot end and when reaching it by pushing very gently I start to see filament coming out as opposed to pushing really hard and barely anything coming out previously. If I do that and return the Z-axis to its position then resume the print it continues until that happens again.
My bed is leveled as best as I can, I downloaded the bed leveling G-codes that help a lot to achieve good adhesion, my prints look pretty much perfect, smooth lines very pleasing to the look and touch, until what I mentioned above happens.
I don't understand what could be the reason that my filament would just bind up like that and snipping it off and inserting a new piece there's no sign of the issue whatsoever.
Notes for what it's worth:
- I'm using cheap black PLA 1.75 mm
- Hotend temperature 200 °C
- Bed temperature 60 °C
- Printing speed 50 mm/s
- The extruder pulley (white wheel with the bearing) bolt is not tightened to the end as recommended on the internet
- The spring bolt on the extruder is not tightened also, as I see there are marks on the filament that went past the extruder wheel, anyway I tried tightening it for the sake of it and it didn't help
- My extruder arm is not cracked
- The gear (brass wheel) doesn't seem to be damaged