Why you need a temperature controlled environment

I have my R2's in a basement that varies in temperature by up 15F. I found as the temperature changed I had to change the offset in the eeprom. I decided to find out why. The R2 re-zeroes from the bottom, it is 250 mm from the hotend. Below is a first order approximation of offset change vs temp change.

ABS changes 1 part in 10,000 per degree C. The bed height is 250 mm, therefore the offset changes 0.025 mm per degree C.

 

I print on micro porous glass. The texture of the glass allows me to use hair spray without it showing, as hair spray does on mirror finish regular glass. The difference between a really good finish and just okay is .02 mm. .05 mm off will rip the face off the glass or not adhere depending on the error direction. I use a .2 mm first layer.

The portable air conditioner I installed is not powerful enough to regulate the basement temperature. I guess I will have to put in a 22,000 BTU unit and pull in the wiring.