I have been having trouble with my cr10s pro V2, although I have replaces most of the parts in the extruder and the printing assembly as well as levelling and adjusting the z offset, the extruder gears tend to skip very often, cause prints to fail. Lately, the printer has been able to do the first layer of a raft fine, but then begins to under extrude and skip. Please help.
This sounds more like a nozzle or heat problem
When the nozzle is hot and a few cm off the bed, can you manually push filament throught it?
Also, just in case you’ve had a brain fart, you didn’t, per chance, switch to a different type of filament like (for example) ABS while you were previousley printing PLA, and forgot to adjust the temperatures accordingly?
Actually, even if you are printing the same TYPE of filament, different manufacturers can include additives that change the desired print temperature. Double check that what you’re printing at is what’s recommended.
Also, while I’m on the subject of filament temperatures, I have a roll of PLA+ that prints best 40C BELOW the temperature recommended on the label, so sometimes the manufacturer doesn’t even get the label right.
Try raising the hot-end temperature 20C and see if it prints consistently.
I would agree that all the other mentions are what you should be checking. You absolutely should be checking your temps. That said I have a very similar issue with one of my printers. It would print small items fine larger more complex things it would stop. very large prints it would stop extruding partway along and on occasion after skipping ten or twenty layers start extruding again (in mid air).
After a massive effort changing and swapping parts. (in the end the only parts not modified was the steel skirt, this doubled the printer cost plus a bit more, add labour and that I ended up needing to pay a commercial printer to print time sensitive prototypes it was around 6 times the printer cost) The issue was the extruder stepper was over heating and would just seize and stop extruding. Something else to check the stepper should not be getting exceptionally hot during use. If you touch it and it is very uncomfortable something is wrong with it.
Definately confirm your nozzle size is correct in the slicer as well, If the slicer thinks the nozzle is large you could have the issue.