Spent the weekend swapping profiles on my Zero and the difference is wild

Ran into the same wall-climbing-over-infill problem on my Zero last year and ended up hand-tuning the max flow rate down til the walls stopped towering over the top layers. Took a few test cubes and alot of guessing. Wish I'd just grabbed a proper profile set back then instead of fumbling through it myself.

The fan thing really hits home too. My ABS prints used to have this faint banding every few centimetres up the sides and I could never pin it down. Turned out the exhaust cutting in and out was cycling the chamber temp slightly, and the parts showed it. I just dropped mine to a fixed low speed after the first layer and that alone cleaned most of it up, so I can belive a proper PID version would do even better. The bed boost trick makes sense as well. I've been preheating with the door cracked open for ten minutes before starting a job, which works but wastes time and heats the room up. Letting the bed run hotter during warmup is the smarter way to do it. Only thing I'd add from my own trial and error, keep an eye on the first layer when the chamber is still cold. My adhesion gets flaky if I rush the soak, so I let the bed sit at target for a couple of extra minutes even after the chamber reads warm.

I went the opposite way on the fan side of things. Instead of a PID macro I just capped my exhaust fan at a fixed low speed in the printer config and let the chamber drift up on its own. My ABS parts on the Zero stopped showing those bands too, and honestly the air exchange is still enough that I don't get that headache-inducing styrene smell by the end of a long print. Took me one afternoon and a couple of test benches to find a speed that worked. One thing I'd flag for anyone trying the throttled version: where you stick the chamber temp sensor matters a lot. Mine was sitting right in the path of the heated air from the bed at first, so the fan logic kept chasing a number that wasn't representative of the actual air in there. Moved it up near the top rear of the frame away from direct airflow and the cycling settled right down. Curious how the bed boost treats your build surface over time. I've got the textured PEI plate and I've been shy about running the bed above what the profile normally asks for, worried about the coating. My soak routine is just starting the preheat twenty minutes before I actualy need the printer, wich is annoying but free.

This takes me back to when we were wrapping cardboard and foam board around open frames just to keep ABS happy. Never thought I'd see chamber control done properly on a stock machine. One thing I'd flag from my own fiddling, if you test that big enclosure part, run the same file twice, once with the PID fan and once with your old setup, and mark the layer heights where bands showed before. Gives you an honest comparison instead of eyeballing it. Curious wether the bands were worse near the top where the chamber had fully warmed, or spread evenly on yours.