This is how the U.S. Department of Labor describes mechanical engineers: Mechanical Engineers research, develop, design, manufacture and test tools, engines, machines, and other mechanical devices. They work on power-producing machines such as electricity- producing generators, internal combustion engines, steam and gas turbines, and jet and rocket engines. They also develop power-consuming machines such as refrigeration and air- conditioning equipment, robots used in manufacturing, machine tools, materials handling systems, and industrial production equipment.