Solved Auto bed level not working after lead screw upgrade

You need to manually level it (or try the newer branch of marlin with MESH leveling).

 

The Marlin ABL used in the Robo versions of the firmware will take all of the points an calculate a flat plane that intersects all the points and then apply that to the extruder as an offset. Sadly if the bed is skewed enough that will make it work like yours is

 

I used metal shims on the new bed.
Under the braces that hold the bearings.

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@mamejay you also said the front and back printed differently, so it is not out in one direction only! Think about it like this, lets say the front right is lower than any other corner of the bed so it slopes down toward the front and it slopes down toward the right. Now the firmware measures the nine points and sees that the four corner points in the front right are lower so now it tries to compensate, but it can't from point to point, because that is not how the leveling works. In the simplest terms, (although this is not actually what it does) picture it as figuring out the average of all the points and telling itself that is where the bed should be and that is where I am going to print. So since the average height is lower that the left rear it will print there a bit smooshed and since the right front is actually below the average it will be a bit high and unsmooshed there.

This is the reason you need to "paper" level the bed. Make it as level as humanly possible and the averages will be closer to the actual measurements.

A newer version of Marlin is available that has additional math to account for beds that are uneven in sections (warped) but this new Marlin is unsupported by Robo on the R1 series of printers. In the new Marlin both Auto-leveling and a new manual level called MESH handle the bed that is uneven in multiple sections in essentially the same way. If you want to experiment with this new Marlin, there is a thread in the Mods and Upgrades subforum that has all the latest files pre-configured for the R1 series of printers.

 

You cannot escape the reality that manually leveling first will help with this issue. It's just how it is, since Marlin does NOT level from point-to-point, but rather best fits a single flat plane across every point you measure.

 

This is why he harp on it in the troubleshooting of printing problems. Glad you got it sorted!

 

No. I don't know of one. Be tough since it only impacts first layer


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I dont know of one, but its pretty easy to adjust the Z offset in the start up scripts, test print, tweak that number again, test print until you get that perfect first layer.