MMU3 on MK4 - unexpected bonus!
I only fitted the MMU3 to my MK4 yesterday evening, so don't have much experience with it, but I've noticed a really nice feature that I haven't seen mentioned.
No more PETG oozing!
By default the printer unloads the filament at the end of a job. At the start of the next job it does all the bed probing without any filament, so as long as you wipe the nozzle at the end of the last print or the start of the new one, there'll be no mess on the nozzle during probing. Then it homes the nozzle and finishes heating it, then it loads the filament and draws the new longer purge line. The filament doesn't actually start flowing until it's drawn a few millimetres of the purge line, so the nozzle is still perfectly clean.
It's a bit of a game changer in my opinion.
RE:
You can do this with XL as well by doing a fairly large retraction when it puts the tool away. There is a setting for that.
On other printers you could do the same by just putting a extruder command on the end g code. Never tried it, but it should work.
RE: MMU3 on MK4 - unexpected bonus!
Great, no more filament dots from the first layer calibration!