Understanding Bed Leveling and Z-Calibration for 3D Printers

[fog37]

TL;DR Summary

leveling 3D print surface for correct printing

Hello,
I am dealing with bed Leveling and calibration (I guess they are the same process) of my new 3D printer and I realized I am shaky on a few basic concepts:

• Leveling: bed leveling does not mean that the building platform is leveled with respect to the ground, which is what a bubble level would measure...The print bed becomes correctly leveled when the extruder tip remains at a constant vertical distance Z away from the print surface as the extruder tip position, ideally for all possible X and Y coordinates, is moved across the printing surface and over all its points. The print bed may not be "leveled" using the bubble level but be "leveled" relative to the transverse motion of the extruder tip which, I guess, has its height automatically adjusted as the tip is scanned over the surface to maintain it at a constant height...Is that correct?
• Z-calibration: I know that, for Z=0, the extruder tip is not actually touching the print surface but should be at nonzero vertical distance (~100 micron across all (X,Y) points on the bed). That is the Z-calibration which I think is accomplished via a 9-point test: the vertical extruder tip distance is checked and adjusted for 9 different and I guess all points in the area enclosed by those 9 points will also be Z-calibrated automatically...
• Origin: where should the extruder tip be located with it is located at the origin O, the position with coordinates (X,Y,Z)= (0,0,0)? Should the origin O be at the center of the print bed? Or at the front left corner of printing bed?

Thank you!

 

[trurle]

Summary:: leveling 3D print surface for correct printing

Hello,
I am dealing with bed Leveling and calibration (I guess they are the same process) of my new 3D printer and I realized I am shaky on a few basic concepts:

• Leveling: bed leveling does not mean that the building platform is leveled with respect to the ground, which is what a bubble level would measure...The print bed becomes correctly leveled when the extruder tip remains at a constant vertical distance Z away from the print surface as the extruder tip position, ideally for all possible X and Y coordinates, is moved across the printing surface and over all its points. The print bed may not be "leveled" using the bubble level but be "leveled" relative to the transverse motion of the extruder tip which, I guess, has its height automatically adjusted as the tip is scanned over the surface to maintain it at a constant height...Is that correct?
• Z-calibration: I know that, for Z=0, the extruder tip is not actually touching the print surface but should be at nonzero vertical distance (~100 micron across all (X,Y) points on the bed). That is the Z-calibration which I think is accomplished via a 9-point test: the vertical extruder tip distance is checked and adjusted for 9 different and I guess all points in the area enclosed by those 9 points will also be Z-calibrated automatically...
• Origin: where should the extruder tip be located with it is located at the origin O, the position with coordinates (X,Y,Z)= (0,0,0)? Should the origin O be at the center of the print bed? Or at the front left corner of printing bed?

Thank you!

Levelling is usually done by attaching a spring-loaded micrometer gauge instead of extruder, and checking if it reads the same across whole bed. You can adjust bed level with set bolts, planing/sanding or epoxy coating, depending on details of your construction.

Most CNC software place origin in front left corner of the bed. It is a bit arbitrary though.

 

[fog37]

Levelling is usually done by attaching a spring-loaded micrometer gauge instead of extruder, and checking if it reads the same across whole bed. You can adjust bed level with set bolts, planing/sanding or epoxy coating, depending on details of your construction.

Most CNC software place origin in front left corner of the bed. It is a bit arbitrary though.

Thank you trurle. I guess the origin O location, the home position, does not matter because the slicer accounts for that.

My printer has an autoleveling sensor...