MTU has adopted a highly efficient technique, known as lasercaving, to produce contoured holes. It uses a laser to generate flared cooling air holes in high-pressure turbine blades and vanes. Through such holes, the outflowing air spreads more advantageously over the component surface. This improves the cooling action, permits higher turbine entry temperatures and thus improves the engine's efficiency.
Lasercaving: precision work in two steps
To produce the holes, the machine uses a two-stage process. In a first step, a laser drills a 0.25 to 0.85 mm cylindrical hole. Thereafter, a second laser is used to remove material in a manner such that a bellmouth results.