What is the next step after measuring the bed levels?

My Creality CR-10 Max is equipped with a BL Touch sensor for bed leveling.

The bed size is 450 mm x 450 mm.

Here is the 16 measurement points taken from a 4x4 grid:

float  v[] = {-1.15625, -0.7625, 0.1525, 1.13,
-1.1150, -0.5150, 0.2125, 1.650,
-0.8525, -0.215,  0.510, 1.4425,
-0.4125, 0.2649, 1.0350, 1.9050};


Which looks like this:

The bed doesn't look flat or level. To what extent should I try to make the bed flat and level?

It's now a day later, and the bed looks like this (image below) after turning the four knobs using AUX leveling (a helper to locate the nozzle above the knobs), so that the nozzle barely scratches a sheet of paper:

float  v[] = {0.0849, 0.0599, 0.1549, 0.2874,
0.2674, 0.0624, -0.0425, 0.0699,
0.3374, 0.1199,  -0.0150, 0.0199,
0.5399, 0.3349, 0.1899, 0.2074};


I also notice that the bed is slightly concave in its center: using a straight edge (a steel ruler on its side), there is enough room in middle ninth (center square) under the ruler for one sheet of paper.

• Have you leveled the bed before starting ABL? You should level the bed first, the best you can. Also, could you please explain what is X and what is Y? The pattern is pretty consistent except for one outlier (+1.65 mm). If the printer had a single Z stepper this could be explained by the cantilever arm, but I think this one has 2 Z-steppers, right? As it is now, you should not print. Once you get it leveled better, just add G29 after G28 in your start G-code.
– 0scar
Jul 8 '20 at 14:08
• are those 16 values just to assist the user leveling the bed, or are they somehow used by the printer to compensate for the imperfect level / flatness of the bed ? Jul 8 '20 at 19:40
• They are just for information, they are used internally to compensate Z during the first few mm of printing (depending on the fade distance).
– 0scar
Jul 9 '20 at 4:38

Now that you have leveled the bed you are ready to start printing. To enable leveling for printing, you need to add G-code G29 directly after G28 in your start G-code of your slicer.