Ringing Part 5: Checking the modifications
Swapped it with the centrifugal fan from my PBSM. The old fan seems to have some bearing problem, it barely turned when plugged into 5V, while the good fan (same manufacturer and model) turned just fine. The rattling sound is gone now.
I found the nicest acceleration/jerk combination last night, which is 1500 XY acceleration and 2 XY jerk. Slow prints, though.
With that done, I did a comparison print to see whether the residual ringing on the X axis was created by the spring tensioner on the belt, which is the legend that’s going around Reddit. There was no visual difference between a print made with the spring tensioner on, and a print done with the spring tensioner removed. So if you want to feel good about it, just tension the belt manually like I did and forget all third-party tensioning solutions.
I left the springs off.
I’ve done 20 test prints since yesterday, so let’s check those screws. I bought some Loctite 243 (blue) in case I need it.
I rubbed my hand over the screws and none of them are rattling or moving, so they didn’t come loose. I put it back together as it was without Loctite, using an adjustable square to set the table evenly over the Y rods. I also bought some WD-40 Dry PTFE lubricant, and I lubricated all rods and lead screws with it.
I was watching PETG print very closely, and it looks like the nozzle purge line that I’ve put into the start g-code is working against it. It works great for PLA, but the stickier nature of PETG means that a glob of material gets stuck on the side of the nozzle, and that’s what has been giving me problems during the first few layers of the print. The glob catches onto extruded plastic and stops it from laying down, or it gets dropped and becomes a rough spot that the nozzle has to plough through, or it stays on the nozzle for so long that it burns, and then I end up with burned blobs on the top surface.
Printed and attached this Y belt idler, taking care to align it parallel with the frame. It didn’t fix the ringing, but I feel a lot better about it.