Laser net shape manufacturing and repair using a medial axis toolpath deposition method

Abstract

A method is disclosed for laser net shape manufacturing a part or repairing an area of a part comprising providing a CAD model of the part to be manufactured or repaired, digitally slicing the CAD model into a plurality of deposition layers, determining a medial axis for each of the deposition layers of the part or repair area; and depositing a bead of a material in a pattern centered upon the medial axis of each of the deposition layers so as to build-up the material by each of the deposition layer until the part is manufactured or repaired.

Description

FIELD OF THE INVENTION[0001]This invention relates to laser cladding method for fabricating or repairing a part, such as a BLISK, compressor blade or compressor component.BACKGROUND OF THE INVENTION[0002]An aircraft gas turbine engine or jet engine draws in and compresses air with an axial flow compressor, mixes the compressed air with fuel, burns the mixture and expels the combustion gases through an axial flow turbine that powers the compressor. The compressor includes a disk with blades projecting from its periphery. The disk turns rapidly on a shaft, and the curved blades draw in and compress air.[0003]In current manufacturing practice, the compressor is made by forging the compressor disk as a single piece with slots at the periphery. The compressor blades are individually forged or cast to shape with a root section termed a dovetail that fits into slots formed in the disk. Assembly is completed by sliding the dovetail sections of the blades into the slots in the disk. If a bla...

AI Technical Summary

Benefits of technology

[0016]The disclosed invention presents many advantages over the prior art method of layered deposition. By depositing a bead width along the medial axis tool path and its offsets, the number of lack of fusion imperfections in the solid deposit can be reduced or eliminated.

Problems solved by technology

The final product is expensive to produce, as it requires extensive high-precision machining operations.

An error in machining even one of the blades may result in rejection and scrapping of the entire BLISK or it may require an expensive and time consuming repair to render the part useable.

While this repair method is suitable for minor airfoil edge damage, it is not acceptable for more significantly damaged areas due to imbalance problems and potential mechanical property degradation.

Replacement or repair of a damaged blade portion of the BLISK presents a difficult problem with this cast and machine approach.

If all or a portion of a blade breaks off from impact of a foreign body during operation, for example, the BLISK becomes unbalanced.

However, such an approach is both expensive and results in reduced performance.

Past laser cladding techniques have resulted in imperfections and inclusions in the formed or repaired part resulting from incomplete fusion of the melted layers to the underlying substrate or previously welded material.

However, prior LSNM methods have resulted in inclusions or fusion imperfections in newly fabricated or repaired part, requiring that the part either be scrapped or further processed to repair the imperfections.

In addition, past laser deposition methods for repair have not focused on producing accurate shapes and geometries.

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