Definition
A metal-forming process in which a heated sheet of metal is placed over a die and shaped by gas pressure applied to one side, forcing the softened metal to flow into the contours of the die. The process is used with metals and alloys, such as certain titanium and aluminum alloys, that become highly formable at elevated temperatures.
Plain English
A way of shaping metal parts by heating a sheet until it becomes soft, then using pressurized gas to blow it into a mold so it takes the mold's shape.
Context Anchor
Seen in aircraft maintenance and manufacturing discussions about shaped plastic parts such as windows, windshields, and canopies.
Derivation
Hot' refers to the elevated temperature at which the metal is worked, and 'blow' refers to the gas pressure used to push the metal into the die — much like blowing into a balloon to expand it. The combination distinguishes it from cold forming (no heat) and from pressing or stamping (mechanical force rather than gas pressure).
Why Pilots Care
Aircraft plastic parts must keep their proper shape and clarity. If a part made this way is repaired or replaced incorrectly, it can become distorted, weak, or hard to see through.
Analogy
Think of softening a sheet of plastic with heat and then using air pressure to press it down over a mold so it takes the mold's shape — hot-blow forming does the same thing with metal.
Intuition Check
Do not read “blow” as an impact or explosion here. In hot-blow forming, the shaping force is controlled air pressure applied to heated plastic.
Example Sentence 1
The aircraft's complex titanium engine nacelle panels were produced using hot-blow forming to achieve their precise curvature.
Example Sentence 2
Hot-blow forming produced a seamless aluminum panel that reduced weight in the aft fuselage section.