US Patent 7820267 Percussion drilled shaped through hole and method of forming

A percussion drilled shaped through hole formed between a first surface and a second surface of a component and a method of forming the through hole. The through hole is defined by a primary crater, a secondary crater, and a metering hole. The primary crater is formed using laser percussion drilling in the first surface of the component. The secondary crater is formed using laser percussion drilling within the primary crater and substantially offset from a centerline of the primary crater. The metering hole is formed using laser percussion drilling within the secondary crater and extending through the component to the second surface. The primary crater, the secondary crater, and the metering hole define a Coand{hacek over (a)} ramp and provide for the flow of fluid through the percussion drilled shaped through hole according to the Coand{hacek over (a)} effect.