Z 0 is positive

After a lot of tweaking this looks to be the best I can get.
Every adjustment of the plate (3-points) a G32 is a must, G30 and then G29.
Picture below is with 60°C heated bed.

New 8mm thick fine milled cast aluminium plate Ø600mm, what can I expect to get in flatness?

Cheers
Bengt

infiniteloop

@tecno

8mm thick fine milled cast aluminium plate Ø600mm, what can I expect to get in flatness?

That’s a good flatness, except of the front/left and rear/right - hmmm - "corners"?. For a Delta, a square grid as you’ve pictured is inappropriate. See M557: Set Z probe point or define probing grid for details. Instead of defining the grid by X/Y, use R to set a radius.

tecno

@infiniteloop
M557 R225 S75 it is

infiniteloop

@tecno

M557 R225 S75 it is

Within the radius of 225 mm, some points cannot be reached by the probe without mechanical problems. These are not related to the bed but probably to issues with your motion system - to spot these areas, narrow-down your mesh to an S value of 20 or similar. In the next step, you can either solve the issues (but maybe these are inherent to a Delta) or minimise the probing radius in order to get a proper mesh which merely represents the surface of your bed, excluding other factors. Else, you can’t use the result for mesh bed levelling.

tecno

Can somebody explain what @infiniteloop is trying to say as I can not grasp this?

@infiniteloop said in Z 0 is positive:

For a Delta, a square grid as you’ve pictured is inappropriate

@infiniteloop said in Z 0 is positive:

Else, you can’t use the result for mesh bed levelling.

infiniteloop

@tecno said in Z 0 is positive:

Can somebody explain …

Sigh! Let me explain: you published this grid:

Bildschirmfoto 2022-12-13 um 00.36.42.png

That grid is square - to be precise, it has a dimension of 5x5 points. This doesn't match your circular bed very well. That's why I think you might get a better picture using smaller S values, something like this: M557 R225 S20

OK, that's just to draw a better map of your casted print plate. It should cover a larger area than what you get with your current 75 mm raster. Had you ever followed the hint from my first post, you would know what I'm talking about

Now, let's talk about the mechanics:

Bildschirmfoto 2022-12-13 um 00.36.42.png

These two spots don't match the idea of a cast aluminum plate. There must be other reasons. If you follow my advice to generate a more narrow grid, chances are high that you will see even more of these "deviations".

Well, I think these "anomalies" at the edge of your printable area point at mechanical problems (or physical limitations) of your Delta …

… which puts our conversation into kind of a loop (as my nick name implies, I love these): after you have performed and published a better (more narrow) mesh, let's have a new look at my latest post (11.Dec 2022, 17:49).