Mini bed is .5mm out of alignment and it causes issues on some larger prints. What can I do?
When I print something that takes up most of the bed the issue becomes obvious. Sometimes these prints turn out fine. However, some models have failed to print specifically because of first layer issues on the right side of the bed. Here's the first layer of a sign I printed today that highlights the issue. The right side of the bed is too low (not close enough to the nozzle) and the left side is too high. The sign was started immediately after a different print so everything was warmed up. I recently installed the SuperPinda which has generally helped.
When I print small objects in the middle of the bed it prints beautifully. However, the Mini print size is already pretty small. I want to be able to use the whole bed.
I saw the Silicone Bed Leveling Mod the other day mentioned in a different post and I wonder if that is the right approach or if I should contact Prusa.
I used the instructions from that mod document to record the values of the mesh bed leveling process and here is what I got (below). I performed this process immediately following the completion of the sign mentioned above and according to that documentation (basically, preheated to 170/60):
0 +0.253 +0.221 +0.160 -0.092
1 +0.297 +0.405 +0.369 +0.184
2 +0.244 +0.396 +0.446 +0.352
3 +0.182 +0.376 +0.473 +0.482
According to the G29 absolute values to relative converter (from the silicone mod documentation) the front right corner is 0.50mm lower relative to the center of the bed.
Posted Dec 14, 2020, 10:30 PM UTC
The article below fixed a similar issue on one my minis. Followed the "How to check" part and found out that my arm was skewed.
https://help.prusa3d.com/en/article/xz-axis-skew-correction-mini_158518
This could help. I'll try this next.
The bed of my mini was off by more than 1 mm and it still printed very well, except adhesion on the sides, which was inconsistent. Amazing how much the bed level correction can fix.
I leveled the arm followingthe same link. Seems to work, although the amount of correction needed was quite extreme. I renounced to correct the last 0.2 mm.
Seems the problem is fixed. I haven't tried huge prints, though.
I have considered the silicone mod but, before that, I want to check if the Z extrusion is out of plumb, and maybe shim or brace it.
Edited: mm
Alright, I did this fix and it helped a little. The issue is that the bed is warped in two ways. It falls down on the left and right side so the middle is higher. However, the back right corner goes up. There's a .66mm difference between the back right and back left corners.
0 -0.138 -0.017 +0.026 -0.101
1 -0.112 +0.189 +0.295 +0.205
2 -0.125 +0.188 +0.350 +0.369
3 -0.206 +0.149 +0.343 +0.459
I can level the X axis perpendicular to the front of the bed but it will be out at the back. I guess I'm stuck with doing the silicone bed leveling mod unless you have other thoughts?
Silicone might be your fastest fix. You can try checking the hardware.
Start with the bed and see how level it is. If it is really bad, Prusa might send you out a replacement. Get something with a completely straight edge and see if you notice any gaps between the bed and straight edge. Check along the 4 edges of the bed and a cross down the center. Try it with your bed both heated and cold. See if there are any differences. If the bed is really bad then you might have to do the silicone fix or reach out to support with your findings.
Next you could try checking the y axis. Make sure there are no loose screws and the rods are straight.
I just took a straight edge to the bed (without the steel sheet). I checked it cold and warmed up for 5 minutes. My findings confirm what the mesh bed leveling numbers show above. In fact, it appears to be further out of level than the mesh bed leveling indicates. There is an arc in the middle that tapers off left and right. The worst part is the back corners. The gaps appear to get a little worse when it's heated.
Yeah, so at least in my experience the sensor only helps so much in bed leveling.. if it is really bad then the sensor won’t fully compensate. Which seems to be what you’re running into.
I think your options are the silicone fix or reaching out to prusa to see if they can replace it.
I don’t think any of my beds are 100% level, but they aren’t that bad. Maybe .1 or .2mm off, which the sensor seems to be able to compensate for.