Dreaded Hull line
Steve, I'm getting the dreaded Hull line on my box bases. Have tried everything that's out in there on the Internet to try and fix it. The floor always seems to shrink where the floor and walls meet. But yet all the bases I've ever printed of your clocks print out flawless. Is there a secret I'm missing. I've tried making the base box in Fusion, Tinkercad, Bambu studio added fillets, chamfers, change thickness of walls nothing works.
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I was having a really tough time getting the base to stick when designing SP7. Below is a photo from the bottom of an early experiment. Lots of things are going on. The red arrow shows the characteristics of the first lifting off the bed. The blue arrow shows the second lifting off the bed. It is likely more pronounced because most of the printing occurred after the second lift.
The blue squiggly line shows the first layer was probably pushing too hard into the bed. I may have overcompensated for parts not sticking by adjusting the first layer height to be too low.
There may have been other things going on as well. Cheap filament, wrong temperatures, dirty build plate, etc. It was printed on a Prusa MK3 using the default slicer settings for generic PLA. More recent slicer defaults have increased temperatures slightly. First layer speeds and extrusion rates may have also changed. I have also gotten better at adjusting the first layer heights for the proper amount of squishing without smearing.
The main reason for the "X" shaped design in SP7 was because of the layer adhesion issues I was having at the time. The shape quickly becomes narrow as it gets taller so there is very little force pulling trying to pull the corners off the build plate.