scholarly journals Multi-Faceted Monitoring of Powder Flow Rate Variability in Directed Energy Deposition

2021 ◽  
Author(s):  
Felicity Freeman ◽  
Ben Thomas ◽  
Lova Chechik ◽  
Iain Todd
Keyword(s):  
Flow Rate ◽  
Energy Deposition ◽  
Powder Flow ◽  
Directed Energy Deposition ◽  
Powder Flow Rate ◽  
Directed Energy

Discrete Phase Modeling of the Powder Flow Dynamics and the Catchment Efficiency in Laser Directed Energy Deposition with Inclined Coaxial Nozzles

2021 ◽  
pp. 1-37
Author(s):  
Sachin Alya ◽  
Ramesh Singh
Keyword(s):  
Mass Flow ◽  
Energy Deposition ◽  
Flow Dynamics ◽  
Free Form ◽  
Powder Flow ◽  
Process Conditions ◽  
Directed Energy Deposition ◽  
Discrete Phase ◽  
Directed Energy ◽  
Inclined Nozzle

Abstract Laser Directed Energy Deposition (DED) is one of the most promising additive manufacturing processes for restoring high value components. The damaged components can have complex free-form shapes which necessitates depositions with an inclined nozzle, where, the gravity can adversely affect the powder flow dynamics and the powder catchment efficiency (PCE). PCE is defined as the fraction of the total mass flow rate entering the melt pool and a low PCE can render the process inviable. In this paper, the effect of nozzle inclination on the powder flow dynamics and resulting PCEs have been studied. It was found that the powder flow dynamics is altered significantly in an inclined nozzle and results in an asymmetric and skewed powder jet. This affects the powder focusing adversely and the PCE deteriorates rapidly with an increase in the inclination and falls below 20% at 75°. A discrete phase model has been developed to understand the powder flow dynamics at different inclinations and process conditions. The mass flow distribution asymmetry on the focal plane at various nozzle inclinations have been analyzed via the model. The model is able to predict PCEs at different nozzle inclinations with reasonable accuracy. It has been observed that carrier gas flow, particle size and laser diameter affect the PCE significantly and can be used to counter the enhanced powder loss at large nozzle inclinations. Process maps have been developed to identify the favorable, acceptable and low PCE regions for the selection of optimal DED parameters.

scholarly journals Correction to: Characterization and Optimization of Process Parameters for Directed Energy Deposition Powder-Fed Laser System

2021 ◽  
Author(s):  
Daniel Andres Rojas Perilla ◽  
Johan Grass Nuñez ◽  
German Alberto Barragan De Los Rios ◽  
Fabio Edson Mariani ◽  
Reginaldo Teixeira Coelho
Keyword(s):  
Process Parameters ◽  
Energy Deposition ◽  
Laser System ◽  
Directed Energy Deposition ◽  
Optimization Of Process Parameters ◽  
Directed Energy
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