Auto Bed Leveling not correcting bed imperfections.

Hi everyone!

I made a build with a prety large bed, 60x40 cm. So far so good. But there´s one thing I´m not satisfied about: I use an inductive sensor for probing for ABL, but it´s not correcting one particular area of the bed which is a little bent down, making the nozzle far from the bed when over this spot.

Is there any fine tunning to be made on probing ? One thing crossed my mind was the possibiliti of an inapropriate slow speed of the Z axis making it impossible to the printer to compensate in time to print that area. Brainstorming here.

Can anyone help me?

One data my probe is 50 mm away from the nozzle in the X axis.

Thank you so much.

ABL is for working out the angles of a flat bed so you can print flat on it, it is NOT for correcting for dips and lumps in beds.

Repetier firmware has distortion correction. I haven't tried it so I can't vouch for how well it works. Info: [www.repetier.com]

Thank you guys for the answers!

Marlin has a mesh bed levelling function, which CAN be used to correct for dips and lumps in the bed.

You are incorrect

all it does is average out the measured points and define that as the ground plane, any dips it will not stick there, and any lumps the layer get squished

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Dust
You are incorrect

all it does is average out the measured points and define that as the ground plane, any dips it will not stick there, and any lumps the layer get squished

Well I'll be darned. You're right. Here I was thinking that all those measurement points were actually doing something more useful than a simple 3 point measurement would achieve.

You wouldn't really want to have the nozzle follow the undulations in the bed surface- all you prints would be as distorted as the bed surface.

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Ultra MegaMax Dominator 3D printer: [drmrehorst.blogspot.com]

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the_digital_dentist
You wouldn't really want to have the nozzle follow the undulations in the bed surface- all you prints would be as distorted as the bed surface.

Accepting that it's always going to be better to have a flat (and level) bed, the approach Repetier-firmware takes seems quite pragmatic. It follows the mapped surface for the first layer, and then lets you define a Z height over which the imperfections will be averaged out, so that the majority of the model is distortion free but you still get the best chance of a good first layer.

Does it work?

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Ultra MegaMax Dominator 3D printer: [drmrehorst.blogspot.com]

No idea

Quote
Dust
You are incorrect

all it does is average out the measured points and define that as the ground plane, any dips it will not stick there, and any lumps the layer get squished

I actually added an alternative to Auto Bed Leveling a little over a year ago, which I called Mesh Bed Leveling that actually can compensate for imperfect build beds.

See [forums.reprap.org]