Creality CR-10: Too much friction/resistance in the filament detector
I had an issue with printing tall chess pieces, where there was a high chance of them coming off the bed mid-way through. This led me to investigate the friction introduced by the filament detector, and the upward pull that this was exerting on the print head.
This filament detector effectively has a straight 40mm tube that the filament passes through, although the filament is clearly not straight as it leaves the reel. I was able to suspend a 500g weight from the end of the filament due to the combined affect of the detector friction and reel/drum load.
By-passing the detector has completely fixed my printing problem.
I suggest the detector design should be changed. The "tube" should be replaced with more of a funnel (i.e. large opening at the top, tapering down to a smaller hole) and maybe the micro-switch could be replaced with an LED/Opto sensor pair.
More details for anyone interested can be found here: http://captainbodgit.blogspot.com/2021/03/filament-pull-affecting-3d-print.html