What does a mechanical engineer do?

Simply put, "mechanical engineering deals with anything that moves," according to the Fu Foundation School of Engineering and Applied Science at Columbia University. Mechanical engineers still use basic components that have been known and used for centuries ‒ such as wheels, axles, levers, screws, springs and hinges ‒ to make machines such as vehicles, farm machinery, household appliances, robots and industrial equipment. Mechanical engineers also design sub-assemblies for these machines, including control systems and instruments as well as individual parts.

Movement can be powered by the muscles of humans or animals, heat and pressure of combustion, hydraulic or pneumatic actuators, electromagnetism, gravity or springs of all shapes and sizes. Therefore, a mechanical engineer must be familiar with all of these basic motion and power components in order to design more complex devices. For instance, in an automobile, the starter motor uses electromagnetism; the engine is powered by expansive pressure from the combustion of gasoline; the power steering, brakes and automatic transmission use hydraulic pressure; and the suspension system uses springs.

Mechanical engineering is one of the broadest engineering disciplines, according to the U.S. Bureau of Labor Statistics (BLS). Mechanical engineers must have a basic working knowledge of many other areas of engineering, including structural, aerospace, computer and electrical engineering. Additionally, they should be familiar with instrumentation and control, manufacturing processes and materials in order to design devices that can be built efficiently and at a reasonable cost.

Critical skills needed in mechanical engineering are an in-depth understanding of physics, mathematics and materials. This knowledge allows engineers to calculate failure conditions based on the dimensions of a part, the properties of its material and the conditions under which it will operate. An engineer can then specify the required dimensions and materials of a part so it can withstand a given force.

Engineers work with many types of materials, including metals, ceramics, polymers and composites. In "Mechanical Behavior of Engineering Materials" (Springer, 2007), Joachim Roesler, Harald Harders and Martin Baeker write that it is very important for mechanical engineers to study the mechanical behavior of materials. Knowing the properties of these materials, such as their density, hardness, tensile strength, bulk modulus and bending strength, allows mechanical engineers to calculate how these materials will perform under stresses such as compression, tension, bending and twisting as well as under various environmental conditions of temperature, pressure, corrosive gasses and liquids, and even radiation. They also need to be able to predict how these materials will stand up over an extended period of time.

More and more, mechanical engineers rely on computer-aided design (CAD) and computer-aided manufacturing (CAM) systems, so proficiency with computers is essential. According to theUniversity of Pittsburgh website, "To design all the machines that use and produce power, today's mechanical engineers use CAD / CAM drawing programs to draft their designs exactly before any manufacturing and testing is done." In addition to speeding up the drafting process, CAD systems allow for quick and easy modifications of designs, three-dimensional (3D) visualization of finished parts and assemblies, and rapid prototyping using 3D printing and computer-aided manufacturing (CAM) software with computer numeric controlled (CNC) machine tools. A comprehensive list of necessary skills and abilities for mechanical engineers can be found at MyMajors.com.