Product Code: ICA12_304

A Verified Model of Transient and Residual Stresses in Laser Direct Metal Deposition
Authors:
Michael Vogel, Manufacturing and Management Group, School of Mechanical, Aerospace and Civil Engineering, The University of Manchester; M Great Britain
Mushtaq Khan, Manufacturing and Management Group, School of Mechanical, Aerospace and Civil Engineering, The University of Manchester; Manchester
Andrew J. Pinkerton, Manufacturing and Management Group, School of Mechanical, Aerospace and Civil Engineering, The University of Manchester; Manchester Great Britain
Juansethi Ibarra-Medina, Manufacturing and Management Group, School of Mechanical, Aerospace and Civil Engineering, The University of Manchester; Manchester
Narcisse NDri, ESI GmbH; Essen Germany
Mustafa Megahed, ESI GmbH; Essen Germany
Presented at ICALEO 2012

Laser Direct Metal Deposition (LDMD) has proved a versatile technique, but a recognized problem that has not been overcome is that transient and residual stresses are generated during the process. These can lead to cracking or to a reduction in final properties and expected lifetime of any product produced by the method.
In order to understand and work toward ways to reduce the stresses, this paper presents a versatile model to predict them. The model couples computational fluid dynamics methods with finite elements methods so that all necessary physical effects including the gas-powder flow, the laser-powder interaction and melt pool dynamics are covered. Inputs to the model are therefore the known LDMD process parameters such as powder mass feed rate and laser power. The model is verified against 316L stainless steel parts built with a coaxial laser deposition system and modeled and measured residual stress distributions agree well.