mechanical engineers plan and design machines, tools, engines, and other equipment or systems that produce or use power. they design products such as instruments, controls, engines and machines as well as mechanical, thermal, hydraulic and heat transfer systems.

they plan and direct fabrication of test control apparatus and equipment in addition to developing methods and procedures for testing products and services. mechanical engineers direct and coordinate construction and installation activities to ensure conformance with engineering design and customer specifications. they coordinate operation, maintenance and repair activities to get the best use of machines and systems. mechanical engineers may also evaluate field installations and recommend design changes to eliminate malfunctions.