Patent ID: 6333069
Filing Date: 2001-12-25
Classification: B23P,C23C,F01D

Abstract:
A method for maintaining the effective cross-sectional area of cooling holes of gas cooled parts during repeated coating operations, the method comprising:(a) providing a gas cooled part having an inside surface and an outside surface, and having a protective coating on the outside surface;(b) forming a cooling hole extending through the part and through the protective coating, the hole having a predetermined cross-sectional area larger than a desired effective cross-sectional area for the cooling hole;(c) applying an insert over the inside surface, the insert having an opening with a cross-sectional area less than the predetermined cross-sectional area of the cooling hole and the insert opening being aligned with the cooling hole;(d) applying a second protective coating on the outside surface, the second protective coating extending into the cooling hole, thereby forming a constriction in the cooling hole having a cross-sectional area less than the predetermined cross-sectional area of the cooling hole; and(e) removing the insert from the inside surface, whereby the effective cross-sectional area of the cooling hole and therefore the cooling gas flow rate through the cooling hole is determined by the constriction formed in the cooling hole by the second protective coating.