How to start levelling from scratch?

I have quite unsuccessfully tried to implement auto bed levelling on my Cartesian printer many times. I suspect that I now have my Marlin 1.1.8 FW pretty messed up. My main issues are with understanding probing point coordinates, and z offset. If I were to load a fresh copy, where do I start to configure it correctly? I’m thinking of first starting with manual levelling as I have had that running fairly well. But when I try to add ABL, things get ugly. Anyone know of a good internet resource? I’m sure that I have exhausted them all.
Thanks for any guidance and suggestions.

Lets See if we can get you running.

We will start Post a link of your current configuration.h file.

And note any changes you may have made.
or
Do you have the 3D printer settings that worked before you tried to implement auto bed leveling. We can also start from there.

Edited 1 time(s). Last edit at 06/26/2018 09:27PM by Roberts_Clif.

Prior to trying to bring up a bed leveling system.... Make sure you can print small objects (such as a calibration cube) in the center of the bed.

If you don't have the setting dialed in well enough to do that... It will be almost impossible to get the bed leveling system working correctly.

Should I enable the 0,0 at center of bed option in Marlin?

Here is my Configuration.h file where I left it out of frustration. Thanks for a cursory review.

I am starting with a fresh copy of BugFix 1.1
With the following enabled, Home All stops at each end stop.
#define BED_CENTER_AT_0_0
When I send G0 X0 Y0, X is about 60mm toward the bed center from the left edge of the bed, or 190mm from what it thinks is 0. Y is about right at 108mm from front edge toward the center.
Am I on the right track? How do I get it to properly center before I attempt the cube?

Quote

#define BED_CENTER_AT_0_0

this is normally only used for delta printers, with a Cartesian style printer 0,0 is set for front left corner of the bed.

Quote

#define X_MIN_POS -90//-50
#define Y_MIN_POS -60//-20
#define Z_MIN_POS 0

set these to 0

OK, I think that I have all necessary changes made, but unsure of the following:

#if ENABLED(AUTO_BED_LEVELING_3POINT) || ENABLED(AUTO_BED_LEVELING_UBL)
#define PROBE_PT_1_X 80
#define PROBE_PT_1_Y 80
#define PROBE_PT_2_X 250
#define PROBE_PT_2_Y 80
#define PROBE_PT_3_X 250
#define PROBE_PT_3_Y 210

I have not been comfortable identifying these probe point coordinates. Example:
#define PROBE_PT_1_X 80
#define PROBE_PT_1_Y 80
Will this direct the probe to travel to X80 Y80? From what point, X0 Y0?
And then:
#define PROBE_PT_2_X 250
#define PROBE_PT_2_Y 80
Also from the same X0 Y0?

With the current Configuration.h settings, when I send G0 X0 Y0, the Probe goes to (approximately) X32 Y60 (as measured from the front left corner of the glass bed.
G28 sends all to HOME positions.

How do I get a print to start at center of bed? Adding a script to my slicer?

Thanks for your help.

First test print started in right rear corner with the nozzle about 4.2mm above the bed.
ABL didn't seem to perform well, if at all. Probed at X105 Y130, X102 Y 94 as best I could witness.
Any suggestions about what to tweak? Thanks for the help.

When you do a G28, is the nozzle off the bed and how much. If its to the left of the bed edge,then this will be a - X min and same for Y if its off the front.

eg.
#define X_MIN_POS -15
#define Y_MIN_POS -4

with the right values it should set X0 Y0 to be at the corner of the bed.


#define X_BED_SIZE 210
#define Y_BED_SIZE 210

This is the max print size of the bed


The position on the bed that a print is done depends on the slicer being given these bed sizes and where the stl part is positioned on the bed when it is sliced,
You cannot alter the position if you just have the Gcode of a previously sliced part..


Let us know what your probes X Y offset from the nozzle is and bed size then i can check your min/max probing locations

G28 send all to endstops. The nozzle is positioned off the bed to the front left, approx X45 Y0 (Y in line with front edge of glass).
LCD reads X0 Y0 Z-1.
Bed is 210 x 210 x 210.

Edited 1 time(s). Last edit at 06/28/2018 02:54PM by nkuck.

So if you set
#define X_MIN_POS -45 , you can probably edit this directly in the eeprom using repetier host or pronerface.

Then send a G28 followed by a G0 X0 Y0 Z1 the nozzle should be at the corner of the bed

Ok, you got the nozzle to the left front corner of the bed. Thanks.
The nozzle is a little too high; air printing.
Now how do I set the coordinates for a 3-point ABL?

So your probe offsets are X-25 Y-50, to the left and in front of the nozzle.
The probe can reach X min Y min ok , and X max-25, Y max-50 ok

Try

#if ENABLED(AUTO_BED_LEVELING_3POINT) || ENABLED(AUTO_BED_LEVELING_UBL)
#define PROBE_PT_1_X 10
#define PROBE_PT_1_Y 10
#define PROBE_PT_2_X 175
#define PROBE_PT_2_Y 100
#define PROBE_PT_3_X 10
#define PROBE_PT_3_Y 150
#endif


This should probe 10mm from the front left front right and rear left of the bed, if my math is correct

Close, but I will try to adjust.
Thanks for all of your help.

Ok, got the movements where I like them, but still struggling with the z-height from bed. It may end up being my inductive probe/mounting, or an offset setting. Continuing to investigate.