Have had my ender 3 for approx a month now with no issues. I changed my nozzle from a .4 that it came with to a .2 that I ordered. I leveled the bed using the paper method. Now every time I try to print, the nozzle is right up against the bed & I can't print, even though I leveled it before hand. Have leveled the bed several times and keep getting the same thing...fine during leveling but way too close during printing. I did notice that the new nozzle sits up a little higher than the one that it came with. Just to check to see if it was in fact the nozzle causing the issue, I put the original nozzle back in and it prints just fine. Not sure how to fix this. Please help.
Make sure you do it right:
The paper method is great to get an approximation, but as some already mentionned: things expand when heating up causing shifts in the bed level.
I just level the bed while printing the first layer, this is in my opinion the only way to REALLY get it right (even though it is best to "paper-method" level the bed beforehand)
Just print this: http://www.thingiverse.com/thing:3235018
and adjust the bed knobs while the firrst layer is being printed.
You should look for a good squashed line but that cannot be rubbed loose with the top of your finger (or a toothpick if you don't want to make the bed filthy) in which case the nozzle is too high up.
hope i helped
Are you levelling when the bed is at printing temperature? I find the bed, when cold, sits at a different height than when hot.
Sounds like the ZStop Sensor needs to be adjusted for the new nozzle. I Always do this when nozzle changing, not all nozzles are created equally!
How do i adjust the zstop sensor?
This video that Chuck form his channel called CHEP explains it at the 1:30 mark.https://youtu.be/mDNo1yyGosI