Partial Answer Why do prints break free?

I have wondered about this since I started to print 3D.
I listened to the various theories about fast cooling of areas, drafts that flow over prints , and others.
You might have a fantastic day where you could just about print a pin vertically, and the next day everything seems to float off the table.
OK Here's my theory. " It's not the heat, it's the humidity! ".
Girls, for years, have known that hair spray can glue anything down, but they have also known that the humidity can undo it.
Well, let's hear your theories! Frank

 

I'm not sure that's the case as I live in Colorado with very little humidity and I've had parts break free. Seems like PLA is the worst culprit, but I can't pull a PETG part off of a warm bed to save my life without warping it.

 

I don't have a problem with PLA, only ABS. It usually starts as a warpage at the rear of the print.
Haven't tried PETG yet.

 

differential expansion/contraction rates and temp changes during the print.

 

I just ran ran a 10mm column 120mm high, vertically. To be on the safe side, I used a 10 loop, attached skirt. It worked out great.
Frank

 

makes sense as your increasing the surface contact area, and spreading the directional forces out lowering the force per square mm similar to laying a newspaper over a stick on a table and breaking the stick

 

The thing is, I was wondering if anyone has come up with 'tricks' to circumvent this.
The edge lifting is just the beginning of breaking free. Maybe something like heating the table hotter, or blowing hot air across the printing. Every bit of useful info helps. Frank

 

for PLA i have the bed temp set to 54 degrees, large prints the fan kicks on after the 2nd layer but for small prints i kick it on the very first layer.