Patent ID: 8555501

Claim:
A method of manufacturing a blade for a turbomachine by superplastic forming and diffusion bonding a first layer, a second layer and a membrane, the membrane being disposed between the first and second layers, the method comprising: applying a stop-off material in a first predetermined pattern between the first layer and the membrane so as to prevent a diffusion bond from forming between the first layer and the membrane across said first predetermined pattern; and applying additional stop-off material in a second predetermined pattern between the second layer and the membrane so as to prevent a diffusion bond from forming between the second layer and the membrane across said second predetermined pattern; wherein the first and second predetermined patterns are arranged so as to allow a diffusion bond to be formed along the blade tip edge, the diffusion bond along the blade tip edge extending across the blade in a chord-wise direction; the first and second predetermined patterns are applied so that over at least a first portion of the blade chord at the blade tip, a greater portion of the first layer at the tip edge, extending in a span-wise direction, is diffusion bonded to the membrane than the opposing second layer; the second pattern is applied such that it defines one or more strips arranged in a span-wise direction, the strips being void of the additional stop-off material; the second pattern is applied such that it defines one or more dots, the dots being void of the stop-off material; and the second pattern is applied such that one of the one or more dots are located between one of the one or more strips and the blade tip edge.