Editing Mechanical engineering (section)

===Design and drafting===
[[File:Mech 2 3D.png|thumb|right|A CAD model of a [[mechanical seal|mechanical double seal]] ]]
{{main|Technical drawing|CNC}}

[[Technical drawing|Drafting]] or technical drawing is the means by which mechanical engineers design products and create instructions for [[manufacture|manufacturing]] parts. A technical drawing can be a computer model or hand-drawn schematic showing all the dimensions necessary to manufacture a part, as well as assembly notes, a list of required materials, and other pertinent information.<ref>{{Cite web|url=https://www.solidworks.com/product/solidworks-3d-cad|title=SOLIDWORKS 3D CAD|website=SOLIDWORKS|language=en|access-date=9 September 2018|date=27 November 2017}}</ref> A U.S. mechanical engineer or skilled worker who creates technical drawings may be referred to as a drafter or draftsman. Drafting has historically been a two-dimensional process, but [[computer-aided design]] (CAD) programs now allow the designer to create in three dimensions.

Instructions for manufacturing a part must be fed to the necessary machinery, either manually, through programmed instructions, or through the use of a [[computer-aided manufacturing]] (CAM) or combined CAD/CAM program. Optionally, an engineer may also manually manufacture a part using the technical drawings. However, with the advent of [[Numerical control#CNC arrives|computer numerically controlled]] (CNC) manufacturing, parts can now be fabricated without the need for constant technician input. Manually manufactured parts generally consist of [[thermal spray|spray coatings]], surface finishes, and other processes that cannot economically or practically be done by a machine.

Drafting is used in nearly every subdiscipline of mechanical engineering, and by many other branches of engineering and architecture. Three-dimensional models created using CAD software are also commonly used in [[finite element analysis]] (FEA) and [[computational fluid dynamics]] (CFD).