EDM method for multi-lobed cooling hole

摘要

A method for forming a cooling hole extending from an inlet on a first surface of a wall to an outlet on a second surface of the wall includes forming a diffusing section of the cooling hole, and a trailing edge on the outlet by electrical discharge machining, and forming longitudinal lobes in the diffusing section. The metering section extends from the inlet on a first surface of the wall towards the second surface of the wall. The diffusing section extends from the outlet to one end of a metering section located between the inlet and the outlet. The outlet is substantially linear or convex at the trailing edge and the lobes are separated by longitudinal ridges.

主权项

1. A method for forming a cooling hole extending from an inlet on a first surface of a wall to an outlet on a second surface of the wall, the method comprising:
forming a metering section of the cooling hole, the metering section extending from the inlet on the first surface of the wall towards the second surface of the wall; forming a diffusing section of the cooling hole by electrical discharge machining, the diffusing section extending from the outlet to one end of the metering section located between the inlet and the outlet, wherein forming the diffusing section comprises:
forming a first lobe that diverges longitudinally and laterally from the metering section and has a trailing edge;forming a second lobe that diverges longitudinally and laterally from the metering section and has a trailing edge; andforming one of (1) a transition region having a portion that extends between the first and second lobes and a downstream end adjacent the outlet so that the downstream end is at least axially coextensive with the trailing edges of the first and second lobes and (2) a third lobe that diverges longitudinally and laterally from the metering section and has a trailing edge; forming a trailing edge on the outlet by electrical discharge machining, wherein the outlet is substantially linear or convex at the trailing edge.