Curious if anyone else has been experiencing this; every couple of prints my nozzle gets out of alignment and with starts digging into the bed, or raising way too high. I’ve had my A350 for roughly 2 months and it started pretty good, but after like a month this behavior started. I had to re-calibrate everything and everything was fine for a bit. But now it’s happening pretty much every day, it’s like one of the z axis’s are getting slightly out of sync with the other.
For starters, I pretty much have to re-calibrate daily. Normally, I calibrate my bed using the auto calibration and the stock magnetic bed, but pre-heat the system to a hot end temp of 200 and bed temp of 70 using OctoPrint. This keeps the bed and hot end a lot closer to where the surfaces would be when actually printing due to expansion when heating and blah blah. Anyways, the temp stays consistent throughout the calibration process and at the end I use a feeler gauge of 0.1mm to get the the z offset set. Then in my pre-print config I just have the machine load up the mesh before printing with a M501.
After a calibration the first few prints are just “OK”, meaning they get solid adherence but lots of stringing and blobbing, very poor bridging, and even worse angles (anything over like 50-60 degrees starts looking like a Salvador Dali painting), but overall the prints come out relatively respectable. Nothing near my Ender 3 though… Right now I suspect this is because my bed is too close to the nozzle, so I’m testing that out now… but as I’m writing this out I’m realizing that this might actually be because the z-axis is going out of alignment mid print. It could be one side getting lower than the other, bringing one side of the print closer to the bed, thus dragging up the last layer a bit and causing this stringing/blobbing… I have no idea. I’m not an expert, ha!
What triggered me to finally get online and start asking others was when the auto calibration completely failed today. I mean, it started out fine, but then the sensor seemed to stop working and slowly rammed the nozzle down into the bed after each measurement. I didn’t catch it right away, as normally I go do something else when it’s leveling, but after manually adjusting the z at the end I couldn’t save the final result. I redid the calibration (making sure the temp was still on correctly), and watched it. I watched as after each measurement, the nozzle got closer and closer to the bed, until in the top right corner, the sensor seemed to completely give up and the nozzle went straight down into the bed, moved the bed down with it, and then stopped. Then it brought the nozzle back up, and went to the final position for me to manually set the z-offset. So this explains why I couldn’t save the result - it was missing like 15 points still! So, now I have 5 little holes going up the right side of my bed, with increasing depth, ruining my second magenetic sheet from Snapmaker.
Anyways, this is becoming quite frustrating as I’ve gone through a couple of hot ends and 2 magnetic beds because of this. I’ve tried glass sheets too (borosilicate, single pane, extra stength single pane, mirror, you name it), which I have had varying success with…but honestly now I’m terrified to use them for fear of them breaking when the nozzle slams into the bed. I’ve also tried to disable the motors, bring the z to the absolute top of the axis, to get them lined up, then re-calibrate based on that. Then each print I would disable the motors ahead of time, bring the z all the way to the top again to re-align, and then print. Yeah, that failed miserably…
Right now I manually calibrated the 25 points by hand (I have to do 5x5, 4x4 and 3x3 aren’t enough…the bed isn’t flat enough…probably because of all the nozzle ramming that’s been happening, ha!), and it’s printing seemingly fine again now, though the nozzle seemed to start lower than I calibrated it to…but I didn’t measure it.
Has anyone opened up the axis’s to see if the axis needed to be cleaned or something? I’m not willing to open mine up like I would on my other printers…