I’ve tested this print with 3 variation so far, the right “bridge” always break around the same height!
The left and right “bridge” are exactly the same, and the left one is solid!
Any ideas?
Failure seems to be where the overhang gets close to 90 degrees. See if you can change the inside angles of where the handles meet the body
Are you using ZHop? It looks like the nozzle is catching and knocking the unsupported part over. It’s likely the head is moving right to left. When it catches the right tower, it breaks. When it catches the left tower, it bends to the left, but doesn’t break, then returns to it’s normal position.
If ZHop isn’t enough, you could try some supports with 10º overhang, only touching buildplate. Unless there’s some other structure on the back, that would create supports part way up the bottom of those towers. Maybe even as low as 5º overhang. Play with that number and the preview to see if you think the supports would be effective.
If you can edit the model, you could try adding a few 0.4mm wide and whatever your layer height is tall lines connecting the main body to the towers at 2 or 3 different heights. Basically something to anchor those towers to the main body and support them during the build, so they can’t move even if they do get hit by the nozzle. Once the print finishes, cut them away with an exacto knife.
Printing tall and narrow parts is difficult.
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I’m going to check that!
I did a test using Cura and the white breakable support, without prime tower or ooze shield. It printed better than Luban with only the PLA for the part and support. I was suprised!
I’ve been looking on how to set the Zhop, cannot find anything, apart from some gcode line, which I don’t know where it was set in luban. Can you point me where to set this Zhop?
UPDATE: I found the Z hop parameters in CURA, I’m trying a print now from CURA with support from the same PLA as the part. Will report back.
Thanks!
In Luban, Z Hop option is enable in base. The option is in “Materials” (in the upper bar menu) and “Retraction Control” → “Z Hop when retracted”
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I managed to get this print out perfectly by some small design change to remove the need for support and using CURA, which give me more control and better result.
It still looks like you have some surface finish issues on the right side near the top, likely for the same reason you had breakage. But I’d call that good enough 