Distortion
Distortion turns up in 2 fields: heat treating, lighting. Here is what it means to the people in each one.
Distortion in heat treating
Unwanted change in shape or size of a part during heat treatment, such as bowing, warping or ovality.
Dimensional movement from heat treating, split into size change (uniform growth or shrinkage from phase volume changes) and shape change (bend, twist, out-of-round or dishing from uneven heating and cooling, residual stress and sagging). Controls include symmetric design, stress relief before hardening, fixturing, press quenching, marquenching, uniform agitation and gas quenching. Distortion drives grind stock and straightening, so it is usually the costliest heat-treat problem.
"Distortion on the ring gears is 0.006 out of flat, put the next lot on the press quench."
Distortion in lighting
An optical aberration where magnification varies across the field of view.
A geometric optical aberration that causes straight lines in the object space to appear curved in the image. It occurs when the magnification of a lens is not constant across its entire field. The two most common forms are barrel distortion, where magnification decreases toward the edges, and pincushion distortion, where magnification increases toward the edges.
"We need to correct the barrel distortion in post because the wide-angle lens warped the architectural lines."