Quote
G
- G29 I 999
I Invalidate this number of mesh points. (No value = 1)
Yes... We want to start with a totally invalidated mesh so we can fill in locations with 'appropriate' values.
Quote
G
- G29 P2 with the nozzle positioned at each corner and at the middle of the bed
P2: Probe Areas of the Mesh that can’t be automatically handled.
No... Not in this case. We want to see how high up or down each corner (and the middle) is. If it is too dramatic, we can still continue and UBL will work. But it is best to physically level the bed as well as possible.
But independent of all that... We need those values so we know what to fill the rest of the mesh points with. It is too painful to manually probe a 10 x 10 mesh. (What size are you going with? 10 x 10 works very well on the FT-i3-2020)
So we need those values to to guide us when we start populating values for the first iteration.
Quote
G
The docco for T does not indicate a default value, or boolean.
T defaults to a human readable format. We just want to know how badly tilted your bed is so we can see if we should physically level it first... or if we proceed, how we tilt the numbers we fill the mesh with.
We just need numbers good enough you don't damage your printer trying to do the G26 Mesh Validation Print. Once we get the pattern to print... It will be obvious (and quick and easy) to edit any mesh point that is not correct.
Quote
G
- G29 P3 C ?.?? with the nozzle positioned in different areas of the bed to fill in the unpopulated mesh values
P3: Fill Unpopulated regions of the Mesh with a fixed value (C or ).
I guess we're taking a guess based on the output of G29 T0. Seems reasonable.
I just re-read this. This populates a single grid point based on the location of the nozzle?
Could I enhance the output of G29 S-1, say M421 I 0 J 0 Z 0.000000 ; X 1.00, Y 1.00 to populate a mesh point?
Yes... It doesn't really matter what you start with for values so long as you don't damage your printer trying to do the G26 Mesh Validation Print. If you had a Z Probe, the numbers would be very close to correct. But we are going to fill the mesh with best guesses and that is why we want the corners and center of the bed measured. We want to make sure the bed is somewhat level and that the values we put in for the mesh are 'reasonable'.
Quote
G
- G26 (with appropriate parameters to get a Mesh Validation Pattern)
G26 B60 D0 F1.75 H185 K0 L0.2 O0.5 P1 S0.4
Yes... and if you want, you can edit the defaults in the G26.cpp file so you don't have to specify them each and every time. But your values are pretty close to the defaults.
#define EXTRUSION_MULTIPLIER 1.0
#define RETRACTION_MULTIPLIER 1.0
#define NOZZLE 0.4
#define FILAMENT 1.75
#define LAYER_HEIGHT 0.2
#define PRIME_LENGTH 10.0
#define BED_TEMP 60.0
#define HOTEND_TEMP 205.0
#define OOZE_AMOUNT 0.3
BUT... You don't want the 'D' parameter. The whole purpose of the G26 Mesh Validation Pattern is to see how well the bed leveling is working to correct the nozzle height. Typically... I just have the defaults compile the way the machine needs them and I use a G26 P C O2 if I need to generate a pattern.
Quote
G
I'm not actually sure how this works. What are the functions of R and U? And what do I expect to see?
- G29 P4 R with the nozzle positioned over less than perfect areas of the Validation Pattern
P4: Fine Tune the Mesh. Generally used in the form G29 P4 Rnn Xxxx Yyyy.
Again, will this move to the nearest grid point and probe?
The R with no parameter says to "Repeat until either done or told to stop". U is only valid on a G29 P1 and you can not do that because you don't have a Z-Probe. U tells the G29 P1 to probe as far away from any other point that has been probed as possible. It is a way to quickly get an assortment of points spread out across the bed to help you physically level the bed. We are trying to brute force something similar by manually probing the corners and the center of the bed.
Quote
G
Thanks very much for your help so far. I'll let you know how I get on when I get back to this tomorrow.
Post a few G29 T's so we can see your progress. And a few pictures of the G26 Test Pattern will be interesting too.
Between those two things... We will get you get you perfectly tuned quickly.