A mill bit for the manufacture of a wind turbine blade includes an elongate based body having a proximal end, a distal end, an outer surface, and an internal bore that defines an inner surface, one or more flutes formed on the outer surface that defames one or more teeth, and an abrasive coating on at least a portion of the outer surface, wherein the one or more flutes are free of the abrasive coating. An abrasive coating may be selectively applied on the inner surface to provide flutes on the inner surface. Additionally, porting bores may be provided through the mill bit to fluidly connect the outside and inside of the mill bit. A method of making a mill bit is also described.

A mill bit for the manufacture of a wind turbine blade includes an elongate based body having a proximal end, a distal end, an outer surface, and an internal bore that defines an inner surface, one or more flutes formed on the outer surface that defames one or more teeth, and an abrasive coating on at least a portion of the outer surface, wherein the one or more flutes are free of the abrasive coating. An abrasive coating may be selectively applied on the inner surface to provide flutes on the inner surface. Additionally, porting bores may be provided through the mill bit to fluidly connect the outside and inside of the mill bit. A method of making a mill bit is also described.

A blade outer airseal comprising a body having: an inner diameter (ID) surface; an outer diameter (OD) surface; a leading end; a trailing end; a metallic substrate; and a coating system atop the substrate along at least a portion of the inner diameter surface. At least over a first area of the inner diameter surface, the coating system comprises an abradable layer comprising a metallic matrix and a filler. The filler forms at least 20% by volume of the abradable layer with agglomerates or aggregates of oxide particles, the oxide particles having a D50 size 200 nm.

A blade outer airseal comprising a body having: an inner diameter (ID) surface; an outer diameter (OD) surface; a leading end; a trailing end; a metallic substrate; and a coating system atop the substrate along at least a portion of the inner diameter surface. At least over a first area of the inner diameter surface, the coating system comprises an abradable layer comprising a metallic matrix and a filler. The filler forms at least 20% by volume of the abradable layer with agglomerates or aggregates of oxide particles, the oxide particles having a D50 size 200 nm.

Methods for forming a hole in a coated component are provided. The method may include forming a sacrificial layer over a ceramic barrier coating of a substrate, drilling a hole into the coated component such that any spatter formed during drilling deposits onto the sacrificial layer, and removing the sacrificial layer along with the spatter deposited thereon. The sacrificial layer may include a rare earth oxide (e.g., rare earth oxide particles). Intermediate ceramic matrix composite (CMC) component are also provided. The intermediate CMC may include a CMC body, an environmental barrier coating on the bond coating, and a sacrificial layer on the environmental barrier coating, with the sacrificial layer including particles of a rare earth oxide dispersed in a polymeric matrix.

A method of forming an airfoil includes casting the airfoil with an internal cooling circuit and an exterior surface with a positive feature. The exterior surface of the airfoil is scanned with a first probe. A size and a location of the positive feature are identified based on the scan of the exterior surface. A transformation matrix is created with a controller such that the transformation matrix includes toolpath transformation instructions. A transformed set of machine toolpath instructions is created by applying the transformation matrix using the controller to a first set of machine toolpath instructions to align the first set of machine toolpath instructions relative to the positive feature. A contour is then machined into the exterior surface of the airfoil based on the transformed set of machine toolpath instructions.

A method of forming an airfoil includes casting the airfoil with an internal cooling circuit and an exterior surface with a positive feature. The exterior surface of the airfoil is scanned with a first probe. A size and a location of the positive feature are identified based on the scan of the exterior surface. A transformation matrix is created with a controller such that the transformation matrix includes toolpath transformation instructions. A transformed set of machine toolpath instructions is created by applying the transformation matrix using the controller to a first set of machine toolpath instructions to align the first set of machine toolpath instructions relative to the positive feature. A contour is then machined into the exterior surface of the airfoil based on the transformed set of machine toolpath instructions.

Tube forming methods can be used for efficient transition in the production of tubes having varying thickness. Material used to form consecutive tubes may have the same thickness along a separation plane separating a first discrete section from a second discrete section of the material, and the first discrete section and the second discrete section may each have varying thickness in a feed direction of the material. With such a thickness profile, the first discrete section of the material may be formed into a first cylinder having varying thickness and separated from the second discrete portion as the second discrete section is formed into a second cylinder having varying thickness. In particular, the transition between the first cylinder and the second cylinder may be achieved without scrap and/or interruption, resulting in cost-savings and improvements in production throughput associated with forming tubes having varying thickness.

A rotor blade comprises a mount and a blade that extends from the mount along a radial axis. The leading edge includes an indent segment. The leading edge has a leading edge radial length measured along the radial axis. The indent segment has an indent radial length measured along the radial axis. The indent segment has an indent depth. A first ratio of the indent radial length to the leading edge radial length is at most 0.5. A second ratio of the indent depth to the indent radial length is at least 0.05.

A rotor blade comprises a mount and a blade that extends from the mount along a radial axis. The leading edge includes an indent segment. The leading edge has a leading edge radial length measured along the radial axis. The indent segment has an indent radial length measured along the radial axis. The indent segment has an indent depth. A first ratio of the indent radial length to the leading edge radial length is at most 0.5. A second ratio of the indent depth to the indent radial length is at least 0.05.