Studies of thermal distortion and residual stresses of an Inconel 718 part fabricated by the laser powder deposition process

2008 ◽  
Author(s):  
Huan Qi ◽  
Byungwoo Lee ◽  
Yan Gao ◽  
Magdi Azer
2011 ◽  
Vol 227 ◽  
pp. 134-137
Author(s):  
Karim Kheloufi ◽  
El Hachemi Amara

A three dimensional model for direct laser powder deposition process is developed to simulate the geometry and the thermal field in building a single-bead wall (thin-wall). This model was employed using the Fluent commercial code to which several modules were appended (User Defined Functions UDF). The temperature distribution, the geometrical features of the generated structure, and thermal cycles have been carried out. We show that the results analysis can provide guidance for the process parameter selection in LPD. , and develop a base for further residual stress analysis.


Author(s):  
Alireza Fathi ◽  
Mohammad Durali ◽  
Ehsan Toyserkani ◽  
Amir Khajepour

Laser Powder Deposition (LPD) process is an advanced material processing technique which has many applications. Despite this fact, reliable and accurate control schemes have not yet fully developed for the process. In this paper, the problem of controlling the clad height in the LPD process is studied. Due to a faster response of the process to change in scanning velocity over the laser power, the scanning velocity is selected as the input control variable. Since the governing equations of the LPD process are complex for designing a controller, an identified nonlinear dynamic model is used. The model is a Hammerstein model with a linear dynamic and a nonlinear memoryless block. The model parameters are identified offline using experimental data. The controller has a proportional-integral-derivation (PID) architecture. The controller was implemented on the real plant to asses its performance in the fabrication of several metallic parts composed of stainless steel.


2009 ◽  
Vol 11 (1) ◽  
pp. 38-44 ◽  
Author(s):  
Ehsan Foroozmehr ◽  
Dechao Lin ◽  
Radovan Kovacevic

Author(s):  
Mohammad Durali ◽  
Alireza Fathi ◽  
Amir Khajepour ◽  
Ehsan Toyserkani

Laser Powder Deposition technique is an advanced production method with many applications. Despite this fact, reliable and accurate control schemes have not yet fully developed for this method. This article presents method for in time identification of the process for modeling and adaptation of proper control strategy. ARMAX structure is chosen for system model. Recursive least square method and Kalman Filter methods are adopted for system identification, and their performance are compared. Experimental data was used for system identification, and proper filtering schemes are devised here for noise elimination and increased estimation results. It was concluded that although both methods yield efficient performance and accurate results, Kalman Filter method gives better results in parameter estimations. The comparison of the results shows that this method can be used very efficiently in control and monitoring of Laser Powder Deposition process.


2006 ◽  
Author(s):  
Umesh A. Korde ◽  
Michael A. Langerman ◽  
Matthew E. Hainy ◽  
Travis J. Zelfer ◽  
James W. Sears

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