scholarly journals A Hybrid Modeling of the Physics-Driven Evolution of Material Addition and Track Generation in Laser Powder Directed Energy Deposition

Materials ◽  
2019 ◽  
Vol 12 (17) ◽  
pp. 2819 ◽  
Author(s):  
Gabriele Piscopo ◽  
Eleonora Atzeni ◽  
Alessandro Salmi
Keyword(s):  
Experimental Data ◽  
Process Parameters ◽  
Energy Deposition ◽  
Complex Task ◽  
Melt Pool ◽  
Directed Energy Deposition ◽  
Proposed Model ◽  
Directed Energy ◽  
Manufacturing Technologies ◽  
Analytic Models

Directed Energy Deposition (DED) is one of the most promising additive manufacturing technologies for the production of large metal components and because of the possibility it offers of adding material to an existing part. Nevertheless, DED is considered premature for industrial production, because the identification of the process parameters may be a very complex task. An original hybrid analytic-numerical model, related to the physics of laser powder DED, is presented in this work in order to evaluate easily and quickly the effects of different sets of process parameters on track deposition outcomes. In the proposed model, the volume of the deposited material is modeled as a function of process parameters using a synergistic interaction between regression-based analytic models and a novel element activation strategy. The model is implemented in a Finite Element (FE) software, and the forecasting capability is assessed by comparing the numerical results with experimental data from the literature. The predicted results show a reasonable correlation with the experimental dimensions of the melt pool and demonstrate that the proposed model may be used for prediction purposes, if a specific set of process parameters that guarantees adequate adhesion of the deposited track to the substrate is introduced.

scholarly journals Model-Based Feedforward Control of Part Height in Directed Energy Deposition

Materials ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 337
Author(s):  
Qian Wang ◽  
Jianyi Li ◽  
Abdalla R. Nassar ◽  
Edward W. Reutzel ◽  
Wesley F. Mitchell
Keyword(s):  
Laser Power ◽  
Energy Deposition ◽  
Inverse Dynamics ◽  
Feedforward Control ◽  
Layer By Layer ◽  
Model Based ◽  
Melt Pool ◽  
Directed Energy Deposition ◽  
Proposed Model ◽  
Directed Energy

Control of the geometric accuracy of a metal deposit is critical in the repair and fabrication of complex components through Directed Energy Deposition (DED). This paper developed and experimentally evaluated a model-based feedforward control of laser power with the objective of achieving the targeted part height in DED. Specifically, based on the dynamic model of melt-pool geometry derived from our prior work, a nonlinear inverse-dynamics controller was derived in a hatch-by-hatch, layer-by-layer manner to modulate the laser power such that the melt-pool height was regulated during the simulated build process. Then, the laser power trajectory from the simulated closed-loop control under the nonlinear inverse-dynamics controller was implemented as a feedforward control in an Optomec Laser-Engineered Net Shape (LENS) MR-7 system. This paper considered the deposition of L-shaped structures of Ti-6AL-4V as a case study to illustrate the proposed model-based controller. Experimental validation showed that by applying the proposed model-based feed-forward control for laser power, the resulting build had 24–42% reduction in the average build height error with respect to the target build height compared to applying a constant laser power through the entire build or applying a hatch-dependent laser power strategy, for which the laser power values were obtained from experimental trial and error.

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

scholarly journals Hot-Wire Laser-Directed Energy Deposition: Process Characteristics and Benefits of Resistive Pre-Heating of the Feedstock Wire

Metals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 634
Author(s):  
Agnieszka Kisielewicz ◽  
Karthikeyan Thalavai Pandian ◽  
Daniel Sthen ◽  
Petter Hagqvist ◽  
Maria Asuncion Valiente Bermejo ◽  
...  
Keyword(s):  
Heat Input ◽  
Energy Deposition ◽  
Fine Tuning ◽  
Hot Wire ◽  
Process Stability ◽  
Electrical Signals ◽  
Melt Pool ◽  
Directed Energy Deposition ◽  
Directed Energy ◽  
The Stability

This study investigates the influence of resistive pre-heating of the feedstock wire (here called hot-wire) on the stability of laser-directed energy deposition of Duplex stainless steel. Data acquired online during depositions as well as metallographic investigations revealed the process characteristic and its stability window. The online data, such as electrical signals in the pre-heating circuit and images captured from side-view of the process interaction zone gave insight on the metal transfer between the molten wire and the melt pool. The results show that the characteristics of the process, like laser-wire and wire-melt pool interaction, vary depending on the level of the wire pre-heating. In addition, application of two independent energy sources, laser beam and electrical power, allows fine-tuning of the heat input and increases penetration depth, with little influence on the height and width of the beads. This allows for better process stability as well as elimination of lack of fusion defects. Electrical signals measured in the hot-wire circuit indicate the process stability such that the resistive pre-heating can be used for in-process monitoring. The conclusion is that the resistive pre-heating gives additional means for controlling the stability and the heat input of the laser-directed energy deposition.

scholarly journals A novel melt pool mapping technique towards the online monitoring of Directed Energy Deposition operations

2021 ◽  
Vol 53 ◽  
pp. 576-584
Author(s):  
Kandice S.B. Ribeiro ◽  
Henrique H.L. Núñez ◽  
Jason B. Jones ◽  
Peter Coates ◽  
Reginaldo T. Coelho
Keyword(s):  
Energy Deposition ◽  
Online Monitoring ◽  
Mapping Technique ◽  
Melt Pool ◽  
Directed Energy Deposition ◽  
Directed Energy

scholarly journals Influence of High-Productivity Process Parameters on the Surface Quality and Residual Stress State of AISI 316L Components Produced by Directed Energy Deposition

2021 ◽  
Author(s):  
Gabriele Piscopo ◽  
Alessandro Salmi ◽  
Eleonora Atzeni
Keyword(s):  
Surface Roughness ◽  
Residual Stresses ◽  
Surface Quality ◽  
Process Parameters ◽  
Energy Deposition ◽  
Industrial Applications ◽  
High Productivity ◽  
Directed Energy Deposition ◽  
Productivity Process ◽  
Directed Energy

AbstractThe production of large components is one of the most powerful applications of laser powder-directed energy deposition (LP-DED) processes. High productivity could be achieved, when focusing on industrial applications, by selecting the proper process parameters. However, it is of crucial importance to understand the strategies that are necessary to increase productivity while maintaining the overall part quality and minimizing the need for post-processing. In this paper, an analysis of the dimensional deviations, surface roughness and subsurface residual stresses of samples produced by LP-DED is described as a function of the applied energy input. The aim of this work is to analyze the effects of high-productivity process parameters on the surface quality and the mechanical characteristics of the samples. The obtained results show that the analyzed process parameters affect the dimensional deviations and the residual stresses, but have a very little influence on surface roughness, which is instead dominated by the presence of unmelted particles.

scholarly journals Effect of spreading of the melt pool on the deposition characteristics in laser directed energy deposition

2021 ◽  
Vol 53 ◽  
pp. 407-416
Author(s):  
Chaitanya Vundru ◽  
Ramesh Singh ◽  
Wenyi Yan ◽  
Shyamprasad Karagadde
Keyword(s):  
Energy Deposition ◽  
Melt Pool ◽  
Directed Energy Deposition ◽  
Directed Energy

Repairing Automotive Dies With Directed Energy Deposition: Industrial Application and Life Cycle Analysis

2018 ◽  
Vol 141 (2) ◽  
Author(s):  
Jennifer Bennett ◽  
Daniel Garcia ◽  
Marie Kendrick ◽  
Travis Hartman ◽  
Gregory Hyatt ◽  
...  
Keyword(s):  
Life Cycle ◽  
Environmental Impacts ◽  
Energy Deposition ◽  
Repair Process ◽  
Directed Energy Deposition ◽  
Die Life ◽  
Hybrid Repair ◽  
Directed Energy ◽  
Number Of Cycles ◽  
Manufacturing Technologies

Powder-based additive manufacturing technologies are developing rapidly. To assess their applicability, comparison of performance and environmental impacts between additive technologies and conventional techniques must be performed. Toyota manufactures over two million aluminum four-cylinder engines in the U.S. each year via die casting. The dies used in this process are traditionally repaired via tungsten inert gas (TIG) welding and only last an average of 20.8% of the number of cycles of the original die life before another repair is needed. A hybrid repair process involving machining away the damaged areas and then rebuilding them additively via powder-blown directed energy deposition (DED) has been developed. The die repaired via DED resulted in the same life as the original die. The use of DED repair eliminated the need for emergency repairs and nonscheduled downtime on the line because the DED repaired dies last for as many cycles as the original die before another repair is needed. Life cycle analyses were conducted comparing the traditional welding repair process to the DED repair process. The results show that the DED repair process results in significantly less damage to the assessed impact categories except for ionizing radiation. Therefore, it can be concluded that the DED repair process could lessen most environmental impacts compared to traditional welding repair. Further work toward increasing energy and material efficiencies of the method could yield further reductions in environmental impacts.

THERMAL MONITORING AND MODELING OF TI-6AL-4V THIN WALL TEMPERATURE DISTRIBUTION DURING BLOWN POWDER LASER DIRECTED ENERGY DEPOSITION

2021 ◽  
pp. 1-19
Author(s):  
Basil Paudel ◽  
Garrett Marshall ◽  
Scott M. Thompson
Keyword(s):  
Steady State ◽  
Temperature Distribution ◽  
Energy Deposition ◽  
Thermal Capacity ◽  
Thin Wall ◽  
Thin Walled Structures ◽  
Melt Pool ◽  
Directed Energy Deposition ◽  
Directed Energy ◽  
Blown Powder

Abstract The effects of Ti-6Al-4V part size on its temperature distribution during the blown-powder directed energy deposition (DED) process was investigated through dual-thermographic monitoring and a unique modeling technique. Results demonstrate that the duration of dwell times presented to be a significant contributing factor affecting the rate at which a steady-state temperature field is achieved. As a result, the longer wall took significantly more layers/time to achieve a uniform temperature profile within the wall. Maximum and average melt pool temperatures appear to be near independent of part size at a steady state. Finite element simulation results showed that a quasi-steady melt pool temperature may be unique to a layer, especially during earlier cladding process near the substrate and that the layer-wise steady melt pool was achieved within the first few seconds of track scanning. A proposed fin modeling-based temperature distribution was found to predict the thermal profile in a ‘substrate affected zone’ (SAZ) along the scan direction within 5%. A method to predict the onset of the SAZ has also been proposed. Process parameters used for the DED of component volumes are not necessarily optimal for thin-walled structures due to significantly less thermal capacity.

Optimisation of process parameters for deposition of colmonoy using directed energy deposition process

2020 ◽  
Vol 26 ◽  
pp. 1108-1112 ◽  
Author(s):  
B.N. Manjunath ◽  
A.R. Vinod ◽  
K. Abhinav ◽  
S.K. Verma ◽  
M. Ravi Sankar
Keyword(s):  
Process Parameters ◽  
Energy Deposition ◽  
Deposition Process ◽  
Directed Energy Deposition ◽  
Directed Energy
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