This document discusses the major parts of a 3D printer including an Arduino Mega 2560, Ramps 1.4 board, stepper motors and drivers, timing pulleys and belts, bearings, a hot end, threaded and linear rods, a thermistor, ceramic heater, and end stop. It also covers the mechanism of the extruder, 3D printing process, Ramps 1.4 connection diagram, and structure of the 3D printer.