Maker Rob Hopeless developed a primitive stereo lithography 3D printer. For those unfamiliar with "SLA", it's a 3D printing technique involving shooting a laser beam at a vat of liquid plastic resin and gradually solidifying that resin into the desired solid object. While most hobbyists attempt to make thermal plastic extruder-based 3D printers, Rob attempted something more difficult:
I have been working on a UV/Visible cure resin 3D printer using a 405nm laser. I started off thinking if I could mix a Delta Robot and a resin printer in one it would be ultra double awesome.
And as you'll see in his video, it sorta worked: he managed to make a misshapen lump instead of the required hexagon shape. Rob has theories as to why it didn't work, including laser reflectivity from the print bed, transparency of the resin, motion control, etc. Unfortunately, Rob gave up on the SLA idea and reverted the equipment to a more basic X-Y Cartesian robot.
Nevertheless, it's a very unusual design we haven't seen before for a 3D printer. Perhaps someone else can refine this design?