Jeez, where do I even start. This problem made me quit 3d printing for about 6 months and still plagues me to this day. My printer is a Printrbot Simple Metal. In the back right of the print bed the nozzle digs in to the bed causing tape to rip up and the print to fail. In the front left of the print bed it prints so high that it doesn’t even stick to the tape. No, my print bed is not warped. I had this problem when I used a plate of mic6 aluminum and now I am using the Matrix Precision XY upgrade and have the EXACT same issue.
If this is of any relevance, my printer homes to the back right but when probing with G30 after homing all axes it returns Y=MAX rather than Y=0, and when I have the printer go to Y=1 from homing all axes it moves towards me 1mm (WHAT?). I’ll post some numbers to show what I mean.
From cura I press home on X, Y and, Z then use G30
> G30
< Bed Position X: 0.00 Y: 203.20 Z: 0.40
< echo:endstops hit: Z:0.40
Now I send the X axis all the way over to the end and use G30 again
> G30
< Bed Position X: 190.00 Y: 203.20 Z: 0.05
< echo:endstops hit: Z:0.05
Now I move Y towards me and keep X in the same place
> G30
< Bed Position X: 190.00 Y: 13.20 Z: -0.97
< echo:endstops hit: Z:-0.97
Now I move home X and keep Y towards me
> G30
< Bed Position X: 0.00 Y: 13.20 Z: 0.55
< echo:endstops hit: Z:0.55
Now I run G29 (pretty much the same thing)
> G29
< Bed x: 10.00 y: 193.20 z: 0.34
< Bed x: 10.00 y: 10.00 z: 0.55
< Bed x: 193.20 y: 10.00 z: -1.03
< echo:endstops hit: Z:-1.03
I can add much, much more info if needed. Help me, you’re my only hope
Sounds like auto level is messed up.
I find it depends how you implement the auto level (g29).
example: G28 X0 Y0
G28 Z0
G29;
the above homes x and y, then homes z at the location the x and y were homed (back left corner) this initial z homing sets the baseline that ever g29 value is then referenced against, in theory it should matter… in practice I’ve noticed a difference in the levelling coefficients.
My solution G28;
G29;
this homes x and y, then move to the centre of the table to take the baseline Z before continuing with auto level.
Oddly this has helped on most of the printrbots I have played with!
Hopeully that helps!
-Chris from Matrix-Precision 
I remember having a blast trying to figure this out before I figured out there is a specific order you have to follow on homing first, then probing, then NOT homing after probing because if I remember right it deletes the data kept for the adjustment matrix.
Hi I would suggest replacing the sensor and I also use Buildtak on the surface, the filament sticks great to it and allows for your bed to be raise just a little bit higher without causing poor adherance.
k5o52
5
Had the same issue when I just started out with the PB Simple Metal. Eventually I replaced the metal bed/ with one that was more even but in the end fixed it by replacing the sensor (pro tip; buy a few for 5 bucks online)
do you have a script for that mate?
