As part of a course titled Manufacturing and Design Communication, I built a prusa-inspired 3D printer. Most of the components, including the frame, lead screw nuts, and electronics housing were custom made using laser cutters, fablight, 3D printing, and injection molding. With a few other students I decided to improve upon the printer, making it self-ejecting.
The design uses a small servo that drives a lever arm, completely intergated into the printer's electronics and G-code. The printer can accept a queue of prints, and upon the completion of a part will extend the bed, lower the arm, and finally slide the bed back, removing the part cleanly.