Peaks and Valleys in Bed Mesh

Basic Information:

Printer Model: Ender 3 S1 Pro
MCU / Printerboard: STM32F401

I’ll happily provide the klippy.log of it’s needed but at the moment I don’t see much of value in it and it’s mostly filled with the raw probe offsets.

Describe your issue:

I’m struggling to get a good first level print with my Ender 3 S1 Pro. In particular I can’t seem to get rid of some z squish on the left side of my bed, even if I have a bed mesh enabled. I’ve worked really hard to dial in the z-axis and bed leveling, but I can’t get rid of these peaks and valleys in the mesh. Here’s what it looks like (with a 20x20 mesh to see what’s going on) which I find very suspicious. I just can’t seem to get rid of these long front to back valleys no matter how much I tweak things.

Could these be faulty regions? The bed IS a magnetic bed. What else could the problem be?

What type of Z axis sensor are you using?

From what I’ve seen, the intervals between the poles of the magnet sheet are on the order of 2-3mm, not the 50mm or so you see here.

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This is pretty common on printers with v groove extrusion and wheel bearings. An out of round wheel will cause a regular wave pattern as shown here.

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It’s an Ender 3 S1 Pro so it has a BL touch sensor. Honestly it doesn’t seem that bad to me, just weird it’s so uniform however the bed mesh is not fully compensating. I get sections of under extrusion and over extrusion all over the first layer.

@jakep_82 I’m new to 3D printing so I don’t fully grasp what you are saying. Do you mean the x axis wheels (or perhaps the bracket) may be causing this?

I found another thread where all the comments are suspiciously similar to the issues I’m having. I’m going to spend some time working through that thread when I have a moment to see if anything in there helps.

I understand it that way and it makes sense. I would check the wheels. You can probably feel it, when you move the extruder by hand in x direction. Conspicuous is the periodical pathway in x direction.

Good luck, hcet14

Ordinary V roller : largest circumference = 75 mm, smallest : 61.4 mm

If there’s a flat on a roller, the pattern should repeat itself every 60 to 75 mm ; eyeballing the map, the period is roughly 230 / 4 = 57.5 mm. Same order of magintude.

Could also be a crappy roller (had a few that came with out of center Delrin wheels and/or crunchy bearings…). Also heard about rollers without spacer between the bearings inner races : bearing killer. And sometime chinese manufacturers can be cheap on lubricant…

? Do you agree, checking the wheels on X?

I had the same pattern. Changing wheels helped.
To check, you can make a mount for the wheel and dial indicator.
The bl-touch cannot correct this because the curvature of the upper wheels is out of phase. The carriage X tilt oscillates and the z-offset changes as it moves.

@TGC what wheels did you change to?

Transparent polycarbonate from aliexpress with a lot of reviews.
Even cheap ones are better than stock egg-shaped.

You might want to look at

A bit more, but generally very good quality.

I’m very satisfied.

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I am using an Ender 5 Pro. When I didn’t use it for a while and i moved my carriage along the Y-axis i can feel an indentation in the wheels in the position the printer came to a standstill. So there is definitly an issue with the stock wheels. Maybe mine are put on there to tight, i don’t know.
What i do to fix the indentation, rotate the individual wheel by hand. The position towards the other wheels changes and fixed it mostly. And i move the carriage by hand when not in use for longer period of time