Experimental and computational appraisal of the shape accuracy of a thin-walled virole aero-engine casing manufactured by means of laser metal deposition

Abstract

Laser metal deposition (LMD) of metallic powders, especially of high-strength nickel based alloys, allows for the manufacturing of components of high shape complexity and load capacity. However, high temperature gradients, induced during laser processing may have an impact on the product quality, especially when it comes to the geometrical accuracy of thin-walled components. This paper aims to provide a modelling approach of the heat effects during LMD manufacturing of a thin-walled virole aero-engine structure, in order to calculate possible shape deviations compared to the target CAD geometry. Hereby, a model reduction method is facilitated which allows the finite element analysis of such larger components in reasonable time. Major process characteristics as heat input, molten region geometry, material deposition (i.e. layer thickness), temperature dependent material and powder properties, phase transformation, process sequence and convection effects are taken into account. The proposed model aims to decrease time consuming trial-and-error testing effort during process design and development by providing reliable results on the shape accuracy of components. The computed final shape of the final product was compared to 3D measurements on a real demonstrator virole component.