3D Printer Babbling
For a fused filament 3D printer, plastic needs to stay where you deposit it. Working with layers that are 0.08-0.24mm thick, the adhesion of the first layer to the bed is essential. My print bed is leveled at the corners: a microswitch tells the printer where Z=0 is, then I adjust all four mounting screws until the entire bed is in the same X-Y plane as the extruder travels, and is about a sheet of paper's thickness away from it. https://awoo.space/media/hr0OR4VcUZVt5_7Eyu8