Mini 2 Weird Printing Pattern Diagnosis

Hello,

I recently replaced the original tool head of my mini 2 with a SL 0.25 mm tool head. Does anyone know what could be causing these weird patterns on multiple test prints?

Any info would be appreciated.

Thanks!

Z offset is too high. With a bigger nozzle and bigger layer height, there’s more margin of error, but with a .25, you need it dialed in very precisely.

Lower the Z offset by about .03mm at a time and check results.

Gottcha, Thank you! On the mini 2 do you know how much 0.03mm? Currently using -0.9, would 0.03mm be just one step? So -0.91?

Typical ballpark offset for the washer-based leveling is -1.25.

If you have non-standard build plate it can be different, but by spec, the washers are -1.25mm thick. Real-world, it varies between -1.2 and -1.3.

Interesting. Something else may be off because even at -1.1 I was getting major indents, typical of z offset too low. This was only happening at 1 part of the plate though.

If the nozzle visibly moves the bed AT ALL when touching the washer, there’s contamination on the nozzle. This effectively puts the measurement of the bed lower than it really is, so it’s common for people to raise the Z offset to try and compensate. After the plastic is mostly mushed out of the way from touching the first washer, the later measurements are closer to accurate, so having that higher Z offset splits the difference from wrong and right to give a useable space in the middle.

The nozzle wipe works with some plastics like ABS and HIPS, but PLA is just too sticky (and oozy) to be completely reliable.

If you feel like adding a BLTouch to get around the nozzle measuring, I’ve done custom firmware for it. That’s how I run my Mini2, and it’s rock solid.

Oh yeah, I’ve been manually clearing the PLA before it touches the first washer and it seems to perform much better.
I’ll have to look into the BLTouch, looks like a simple addon.

Thanks for the help!