Prusa Mini+ terrible bed adhesion and first layer in top-left corner
Hi all,
My printer has really bad bed adhesion in the area of top-left corner of print bed. It had it since day one, but over a year of use it got worse. The issue is visible on all nozzle sizes, but printing with 0.25mm nozzle in 99% of prints results in print failure. This is the picture of two failed models printed with 0.25mm nozzle: https://imgur.com/w2CRqkF . As you can see the plastic lines barely touch each other, like if nozzle does not press it to the bed at all. Here's successful model literally from the same print as the other two: https://imgur.com/Sk9bh9i (this is the player piece of catan board game, printed using one object at a time).
When printing something utility using 0.4mm and bigger nozzle size the problem is tolerable, but is still prominent. For example, this is the top left corner of a box printed using 0.8mm nozzle: https://imgur.com/Wf3qcU8 . Please note hoe the lines transition from good to bad closer to the corner.
I was blaming the squareness of printer and the wobbly bed surface. X-Z axis were indeed not square with 0.3° difference from being true. Bed was indeed wobbly reported by octoprints bed visualizer: https://imgur.com/JOCvpqf . I expected firmware to be able to compensate for that, but since it didn't I decided to fix both. First the squareness https://imgur.com/a/xuYi704 via inspecting all the joints and then bed level via silicone bed leveling mode https://imgur.com/BkUjoZ5 and https://imgur.com/a/PktqBay . To my surprise, none of that helped at all.
At this point I'm a little bit desperate and looking for help from the community. Does anyone have any idea what should be causing the problem? This issue takes like 20% of build space away from my printer
Best Answer by Serhii:
Hi,
I should have mentioned this earlier: I've installed klipper over the prusa firmware and issue no longer manifests. Thanks everyone for your input.
RE:
Have you changed to the correct preset under "Printer settings" for the nozzle diameter you are currently using?
In addition, the first print with the 0.25mm could just be too high. Can you lower the z-axis offset until the filament is squished onto the buildplate?
Prusa Mini FW4.4.1
RE:
Hi, thanks for your reply!
> Have you changed to the correct preset under "Printer settings" for the nozzle diameter you are currently using?
Yes I did, otherwise I would not get any good prints with 0.25mm nozzle at 0.05mm layer height.
> In addition, the first print with the 0.25mm could just be too high. Can you lower the z-axis offset until the filament is squished onto the buildplate?
It's not my first print with 0.25mm 🙂 Everything you see on this picture https://imgur.com/a/5aDsaC7 was printed on 0.25mm nozzle with 0.1mm layer height. Additionally, if this was the Z offset issue it would present itself more than in just one corner, but it's not.
RE: Prusa Mini+ terrible bed adhesion and first layer in top-left corner
In that case, i'm not sure, why the Pinda probe doesn't recognize this difference and offsets the z height by the correct amount.
As a workaround: Are you currently printing in PLA using the smooth sheet? If so, printing PETG on the textured sheet could give you more leeway when printing, since the groves on the textured sheet allow for a greater difference in z deviation, where the filament still sticks properly to the bed.
Prusa Mini FW4.4.1
RE: Prusa Mini+ terrible bed adhesion and first layer in top-left corner
> As a workaround: Are you currently printing in PLA using the smooth sheet? If so, printing PETG on the textured sheet could give you more leeway when printing, since the groves on the textured sheet allow for a greater difference in z deviation, where the filament still sticks properly to the bed.
@teachtheprints Issue manifests in both PLA on smooth sheet and PETG on textured. I've attached pictures in original post where small print of Catan figurines is in PLA and big model of a box is in PETG.
> Have you worked through this?
> https://help.prusa3d.com/article/squaring-your-mini_158518
@diem Yes, I did. And I did it with a bit more precise tools than a print bed sheet 🙂 Specifically, parallel axis were aligned using Klein Tools electronic level with precision of 0.1°. Angled axis were aligned using PEC machinists square with squareness of 0.0006″.
It's worth to mention my printer was a semi-assembled kit because it was faster to ship. The issue was present since I've unboxed it, but I didn't care much. Now I need all the printing space it can provide.
RE: Prusa Mini+ terrible bed adhesion and first layer in top-left corner
@diem Yes, I did. And I did it with a bit more precise tools than a print bed sheet 🙂 Specifically, parallel axis were aligned using Klein Tools electronic level with precision of 0.1°. Angled axis were aligned using PEC machinists square with squareness of 0.0006″.
Can you clarify how you leveled things in a little more detail? I'm concerned that you think you did a better job than you may have actually done.
0.1° sounds great. But on a 180 mm span, 0.1° is 0.3 mm: 180*tan(0.1°) = 0.3
You have a link to imgur saying you checked the squareness, showing the angle meter on top of the X-axis showing 90.0°, then on the Z-axis showing 0.0°. These angles, within reason, don't matter in comparison to each other, which is why the Prusa article doesn't have you measure them.
What matters for the X-axis is parallelism of the nozzle to the bed. This is why the test for the XZ-axis has you lower the Z-axis until the nozzle is just off the bed, then manually slide the X-axis across the bed, sliding a shim under the nozzle at various points to check the height, making sure it's the same from left to right as you move the X-axis across the bed.
In theory, you could do this by placing a level on the bed, and measuring the angle of the bed along the X-axis. Then put the meter on the X-axis rod and adjust to the same angle as the bed. But, as previously mentioned, ±0.1° over 180 mm span is ±0.3 mm. 0.3 mm is both more variation than a first layer height of 0.25 mm, and certainly larger than you could get using a shim as a feeler gauge between the nozzle and the print bed.
How did you check the Y-axis?
RE: Prusa Mini+ terrible bed adhesion and first layer in top-left corner
Hi,
I should have mentioned this earlier: I've installed klipper over the prusa firmware and issue no longer manifests. Thanks everyone for your input.
You may already have done this but just as a ground check - with a good straightedge and a torch check the flatness of the print-sheet both on and off the bed.
Cheerio,