Printing with A1 with 0.4mm nozzle since last July, no problem at all. I bought along a 0.4mm hardened (black) hot end and a 0.2mm because I thought I needed at some point. Days ago I printed really small gears and used the 0.2mm for the first time, the results are astonishing, the gears teeth almost my fingers skin while handling, so sharp. Then I thought, why not try to use 0.6mm? Then bought a hardened nozzle 0.4mm with interchangeable tips, 0.2, 0.4, 0.6 and 0.8mm at Amazon, it came with 3 hot end rubber boots (people eating those boots for lunch?). Two wrench tools came along to remove and install the tips, without those you cannot remove the installed tip. Threaded the 0.6mm in the new hot end, replaced it on A1, on the LCD panel “Maintenance” changed the hot end diameter from 0.4 to 0.6mm, on Bambu Studio also changed to 0.6mm on top left, and sent a print. After around layer 15 or 20 it ripped off all the printing from the plate and messed up. I was even using glue on that that 0.4mm never gave me that issue. Then I remember I did not run a plate leveling before the print. Of course, the new hot end and tip could be different from the 0.4mm. After send the print again with the leveling along, it printed nicely. Yesterday I noticed the hot end tip was scratching the infill when moving fast over it. I remember seeing this with the 0.4mm with that particular infill, and it makes sense. When printing the infill first, then trying to move over the filling the tip will hit the warm/cold infill lines. I thought the whole head will lift a bit when moving without printing, but in this case it seems it does not. Different from other people complaining quality when using hardened nozzle, I see no difference, of course 0.6mm is 50% faster than 0.4mm but also the printing is less smooth, but totally acceptable for most of printings. It appears more on the top face than side faces. I wonder if having less layers, due layers being 0.3mm 0.6mm nozzle against 0.2mm of 0.4mm nozzle, it will reduce the possibility of separating layers under flexing the part. More thin layers, more chance to separating them. Another pro for 0.6mm is the less chance to clogging filament in the nozzle tip. I wish there was an easier removable front plastic bezel, maybe magnetic?
This is a heck of a wall of text but it sounds like the name of the thing you’re looking for is z-hop on retraction. It’s found in the machine section, with overrides available in each filament section
Thank you Bullocks, I never realized about the z-hop retraction for infill in [Global][others][GCode] menu… this will solve problems here. My son is also complaining about his machine scratching sounds while printing.