Y-Axis Shift
Week or so back I started having an issue with Y-shift on my 2.5s
Rolled back current firmware to the previous version, checked all cables, pulleys, connections for snagging, and tightened the belt by one notch.
Back to nice and smooth prints. The two pieces below were printed over the last two / three days.
Overnight yesterday however I've had another failure, entirely on the y-axis. Major difference last night was overall temperature (hottest day of the year in the UK) and a storm rolling in between 2-5AM (which could correlate with the start of the layer shift). 
Could this be down to power failures to the machine, the y-motor failing or something else entirely?
RE: Y-Axis Shift
heat, humidity, and power problems could all contribute
RE: Y-Axis Shift
While electronics might be part of it, it really looks more like a lowly belt or pulley slip.
RE: Y-Axis Shift
While electronics might be part of it, it really looks more like a lowly belt or pulley slip.
I'll double check, but the belt was tightened and pulley wheel checked last weekend.
RE: Y-Axis Shift
Your photo isn't good enough to tell, but you also have a lot of area where extra perimeters are being printed: and these flat areas tend to curl between infill supports and curled plastic will grab the nozzle as it prints and moves over them. Slow down infill speeds - slow down the cooling fan - try to reduce any curling you see.
RE: Y-Axis Shift
Thanks, will give that a shot 🙂