I have optimistically put the 3D printer away so I could convert the heavy shop into a paint booth. It’s time to write up my findings as I’ve been exploring the boundaries of this new tool. In particular, I want to figure out how I can make thin-walled boxes like hopper cars.
Starting with the same 2x2x2 cm cube I used for the accuracy experiment, I tried printing at various wall thicknesses. Some Internet research explained why the first boxes, which were not rotated, warped on the bottom. Essentially, this presented a large single layer that had to fight surface tension to pull away from the FEP film; as it pulled away its connection to some supports broke, and from there it was a floppy mess until sufficient layers had accumulated to stiffen it. This makes sense, and I tend to follow advice that makes sense to me, so I tried a couple of alternative angles as well as wall thicknesses.
I found a wall as thin as .5 mm was almost printable. When rotated at 45 degrees, it shows some clear defects, as if it has slumped, but kept on printing. At 10 degrees, those were reduced, but a couple of tiny gaps appeared at one corner.
The 1 mm sample did better at 45 degrees, but I believe it suffered from insufficient supports, allowing it to wobble, and producing layers. For some reason the 10 degree attempt at 1mm thickness failed completely, even though it was on the same run as the .5 mm cube; perhaps some residue from the previous attempt disrupted the print.
More experiments will come.