Anycubic Predator calibration messed up

AdrAs

I recently discovered that the calibration of my Anycubic Predator doesn't work well anymore.

I'm getting consitently a heightmap which looks like this:

Side view:

I remember there was a site which showed different kinds of heightmap issues but I can't find it anymore.

I already identified the following possible issues, but testing all of them out is going to take quite some time. I hope someone can help me to identify which one it is by looking at the heightmap.

Printing at very high speeds(160mm/sec) until the printer lost steps had some negative effect on the machine.
- Arm length is not equal anymore
- Some screws are loose
- Something else is no longer tight
Probe got destroyed because it was slammed into the bed twice
- Repeatability of probe was tested, and shows consistent results probing the same point multiple times
Some changes to config.g or other files could have caused wrong settings for calibration

Any thoughts on this, help is really appreciated.

bberger

Looks like each of those dips are near the towers.

My guess would be either effector tilt or the towers not being parallel.

I had bought a Predator second hand a while ago and found out the guy didn't assemble the towers square and parallel. After redoing them my bed is now flat with very little deviation (< 0.15)

AdrAs

Well, when I got the printer everything was fine. After the conversion to duet it was also fine. Unless lifting it off the table, and putting it back up affected it, I doubt that the towers are no longer parallel. And the frame seems to be really rigid. Not sure if it will change anything if I loosen all the screws and put them back on.

dc42

Did you auto calibrate before you probed to get the height map? If so, how many calibration factors did you use, and what deviation was reported after auto calibration?

AdrAs

First M561 to clear any bed transform.
I'm using G32 second Output:
Calibrated 6 factors using 13 points, deviation before 0.725 after 0.063

After that G29. Output: 21 points probed, min error -0.192, max error 0.163, mean -0.008, deviation 0.087
Height map saved to file heightmap.csv