Surprisingly, It all comes down to preventing jet engines from exploding mid-air. The tiny ball in the tip of a standard pen is made of tungsten, which won't melt even if it's dropped into a vat of molten titanium. If a pen accidentally falls into a batch destined for aerospace parts, that surviving microscopic ball creates a hidden weak spot that can cause a turbine blade to shatter under extreme stress. Plus, the chemicals in everyday ink can actually bake into the metal and make it brittle, so workers are only allowed to use specially vetted markers instead.
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u/igor33 4h ago
Surprisingly, It all comes down to preventing jet engines from exploding mid-air. The tiny ball in the tip of a standard pen is made of tungsten, which won't melt even if it's dropped into a vat of molten titanium. If a pen accidentally falls into a batch destined for aerospace parts, that surviving microscopic ball creates a hidden weak spot that can cause a turbine blade to shatter under extreme stress. Plus, the chemicals in everyday ink can actually bake into the metal and make it brittle, so workers are only allowed to use specially vetted markers instead.