Mini 1 Z-axis stuckage (pics)

I’m trying diagnose a Mini V1 which has been a workhorse, but has developed Z-axis inconsistencies. See photos (new account, I can only put one). I suppose it continually/reliably does this squishing. Seems to have inaccurate Z height. Thought it might be the bed wobbling back and forth because of very worn Y-axis bearings, replaced those. Checked the X axis leveling, it’s level I believe.

Suggestions for next steps?

Actually this one might have more than Z-axis problems. I have a Taz5 which has definite Z-axis problems, post on that coming…

Yeah, hard to diagnose with all that’s going on in those prints. The layers appear stacked fairly consistently vertically, but they look somehow wavy, and its hard to tell exact in which axes. Also, the corners look to have some serious over extrusion issues. Have you ruled out extruder and temp issues as the cause?

The fact that the layer lines appear consistent doesn’t make it appear mechanical in nature, but its really hard to say based on a rectangle. maybe your steppers are somehow intermittently missing a step because the driver is failing, wires have frayed and are introducing additional resistance, or the bearings aren’t running smoothly.

I would print some calibration cubes one at a time and verify how consistent the z axis error is. If it’s identical cube to cube, it’s likely a settings issue. Reflash firmware and recheck slicer settings. If z height varies cube to cube, it’s likely something mechanical or electrical is causing aperiodic missed steps.

I have a mini v1 as well. And it has been a workhorse as well.

Is the actual build plate secure? I recently had an issue with my auto-levelling failing and I removed the bed and found that the screws that hold on the build plate were loose. This wasn’t my issue with auto-levelling but I noticed that things had loosened over time. I also noticed my front y-axis had cracked at the bearing and I printed a new one of those. This led to “play” in the Y-axis.

The build plate had a lot of play, I replaced the bearings (y) and it’s pretty solid now. So I don’t think it’s the plate moving around.

Of course this mean that I took the entire build plate off and had a good look around under there.

I had something similar to that on a Taz 6 and it turned out that it was my heated bed not staying on consistently. Instead of staying at a constant temp it was banging on then cooling then banging back on again but it was real consistent and its hard to tell from the pics you posted if that’s the situation but may be worth checking. The boat hull looks more like that than the rectangular block does but that’s kind of what I was seeing with mine. I replaced the heat bed and that fixed it. I was printing with ABS in an enclosure and apparently ABS is particularly sensitive to that sort of temp inconsistency.