I'm printing a large helmet shaped item (interior hollow) that is sized 176 by 183 by 170 mm in XYZ. It is basically the left side of the helmet. I am using ESUN PLA+ filament on a Ultimaker 2 printer with Cura 15.04.6 software. Lots of successful smaller prints prior to this using regular PLA filament.
This print has a shift in +Y (towards front of printer) at a height of roughly 1 and 2 inches. The offsets in Y are 1/8 and 3/8 inches. Shift is same on both exterior helmet edge and interior fill. The print was stopped. Print is largest at base. Print is on glass plate without anything to help adhere such as glue or blue tape. Printed using modified fast settings (0.15 mm layer height, 0.4 mm nozzle, 1.2 mm shell thickness fill density 10 percent. I usually use fast settings without issue for my prints. This time I upped the shell thickness from default 1 mm to 1.2 mm to make it a multiple of the nozzle size as recommended. Issue is not the settings.
I had just started to use the ESUN PLA+ filament and added just a smidgen of oil 2 prints earlier. One was an even larger helmet (over 190 mm in XY) that also shifted. The second was a smaller helmet segment sized 64x176x128 mm in XYZ that was fine.
Now, it could be that the print is too large and the print head is hitting something or just unhappy with software instructions, but I would have expected that at the base where brim and print is largest.
It could be that the print shifted on the glass plate, but it seemed to be adhered on plate until plate cooled (I did not stop the print, so did not see). Having said that, the helmet has a small base where it adheres to the plate (with brim) on helmet flanks and then extends (with support) towards top of helmet shape. So, certainly plausible it shifted. There is no obvious evidence on plate that shift occurred.
It could be that a gear shifted or something causing a Y shift, but I'd expect that to happen more than just twice. And it did not happen to the middle successful print.
It could be the cura software and firmware are too old and don't support large prints well and I should update or that I should use a plugin that extends max plate print size.
Lots of possibilities. Anything obvious such as cura 15.04 does not support this large a print (176x183x170 mm)? I know Cura does not like anything sized over 184 mm (if you check the scale, model turns grey). I suppose I will have to divide and conquer such as trying glue stick on plate and seeing if it shifts. Any comments?