In my learning curve on 3D printing I wanted to get an idea for myself what the expansion of the hot end nozzle was as it was taken from its cold state to printing temperature. I know this has been done before but really wanted to calculate it for myself. I found it to be about 0.11mm. This was valuable as I had been setting the tip of my hot end at 0.02 in or 0.5 mm from the glass, measured cold with a feeler gauge. This would mean that hot the distance between the end of my nozzle and the glass was about 0.4 mm. Probably a little too large of a gap. I think I will start setting my nozzle at about 0.01 in or 0.25 mm from the glass surface (measured cold) to get this distance closer to 0.1 mm when the hot end is heated and ready to print.
Your hot end should, normally be, a piece of papers distance (0.1mm), from your printing bed!! This measurement is considered " level ". And should be your default setting for leveling your hot end on your extruder to your printing bed.
Anything higher WILL cause problems for you while printing, guaranteed mate…
Over extrusion, under extrusion, dips + bits, drooping, etc…
If your not printing at this height, think about it literally… Your printing at a distance thats anywhere from 1 - 5 Z-axis layers above from where you should be, and where your printer thinks you are, extruding layers.
This is why I set Z0 to be Z0 (touching the build plate) while everything is at print temperature.
Then if I tell it my first layer height needs to be 0.2mm then I can be 100% sure when the printer sees G1 Z0.2 that nozzle is exactly (well, within reason) 0.2mm away from the bed.
@ScannerStrap Your math seems to agree with my observation of 0.15mm adjustment requirement for my brass nozzle and glass bed arrangement.
I follow +nop head’s procedure of setting Z height with a cold hotend and applying a 0.2mm adjustment to the result. After a trial print a minor corrective adjustment of -0.05mm is required to set things right.
Ps. I failed to mention that, yes, you should also in fact set your printer to a “level” position while it is at printing temperature.
This is, somewhat of a givin. Though many companies/people fail to mention this in a leveling procedure, due to the the fact that they don’t want a bunch of people to burn themselves while doing it!
