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.

Thermal Monitoring and Modeling of Ti-6Al-4V Thin Wall Temperature Distribution During Blown Powder Laser Directed Energy Deposition

2021 ◽  
Author(s):  
Basil J. Paudel ◽  
Garrett J. 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-laser (DED-L) process was investigated through dual-thermographic monitoring and a unique modeling technique. Results demonstrate that the duration of dwell times are a significant contributing factor affecting the rate at which a steady-state temperature field is achieved. Longer walls took significantly more layers/time to achieve a uniform temperature profile. Maximum and average melt pool temperatures appear to be near independent of part size at a steady state. Finite element simulation results show that a quasi-steady melt pool temperature may be unique to a layer, especially for layers near the substrate. Layer-wise steady melt pool temperatures were 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-L of component volumes are not necessarily optimal for thin-walled structures due to their significantly lower thermal capacity.

scholarly journals An Extended Lumped-Parameter Model of Melt–Pool Geometry to Predict Part Height for Directed Energy Deposition

2017 ◽  
Vol 139 (9) ◽  
Author(s):  
Jianyi Li ◽  
Qian Wang ◽  
Panagiotis (Pan) Michaleris ◽  
Edward W. Reutzel ◽  
Abdalla R. Nassar
Keyword(s):  
Energy Deposition ◽  
Temperature Fields ◽  
Temperature History ◽  
Extended Model ◽  
Thin Wall ◽  
Melt Pool ◽  
Directed Energy Deposition ◽  
Lumped Parameter ◽  
Single Bead ◽  
Directed Energy

There is a need for the development of lumped-parameter models that can be used for real-time control design and optimization for laser-based additive manufacturing (AM) processes. Our prior work developed a physics-based multivariable model for melt–pool geometry and temperature dynamics in a single-bead deposition for a directed energy deposition process and then validated the model using experimental data from deposition of single-bead Ti–6AL–4V (or Inconel®718) tracks on an Optomec® Laser Engineering Net Shaping (LENS™) system. In this paper, we extend such model for melt–pool geometry in a single-bead deposition to a multibead multilayer deposition and then use the extended model on melt–pool height dynamics to predict part height of a three-dimensional build. Specifically, the extended model incorporates temperature history during the build process, which is approximated by super-positioning the temperature fields generated from Rosenthal's solution of point heat sources, with one heat source corresponding to one bead built before. The proposed model for part height prediction is then validated using builds with a variety of shapes, including single-bead thin wall structures, a patch build, and L-shaped structures, all built with Ti–6AL–4V using an Optomec® LENSTM MR-7 system. The model predictions on average part height show reasonable agreement with the measured average part height, with error rate less than 15%.

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 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

How the nozzle position affects the geometry of the melt pool in directed energy deposition process

2019 ◽  
Vol 62 (4) ◽  
pp. 213-217 ◽  
Author(s):  
Abdollah Saboori ◽  
Sara Biamino ◽  
Mariangela Lombardi ◽  
Simona Tusacciu ◽  
Mattia Busatto ◽  
...  
Keyword(s):  
Energy Deposition ◽  
Deposition Process ◽  
Melt Pool ◽  
Directed Energy Deposition ◽  
Nozzle Position ◽  
Directed Energy

From mine to part: directed energy deposition of iron ore

2021 ◽  
Vol 27 (11) ◽  
pp. 37-42
Author(s):  
Himani Naesstroem ◽  
Frank Brueckner ◽  
Alexander F.H. Kaplan
Keyword(s):  
Additive Manufacturing ◽  
Laser Beam ◽  
High Speed ◽  
Iron Ore ◽  
Energy Deposition ◽  
Content Type ◽  
Melt Pool ◽  
Directed Energy Deposition ◽  
Directed Energy ◽  
Melt Pool Size

Purpose This paper aims to gain an understanding of the behaviour of iron ore when melted by a laser beam in a continuous manner. This fundamental knowledge is essential to further develop additive manufacturing routes such as production of low cost parts and in-situ reduction of the ore during processing. Design/methodology/approach Blown powder directed energy deposition was used as the processing method. The process was observed through high-speed imaging, and computed tomography was used to analyse the specimens. Findings The experimental trials give preliminary results showing potential for the processability of iron ore for additive manufacturing. A large and stable melt pool is formed in spite of the inhomogeneous material used. Single and multilayer tracks could be deposited. Although smooth and even on the surface, the single layer tracks displayed porosity. In case of multilayered tracks, delamination from the substrate material and deformation can be seen. High-speed videos of the process reveal various process phenomena such as melting of ore powder during feeding, cloud formation, melt pool size, melt flow and spatter formation. Originality/value Very little literature is available that studies the possible use of ore in additive manufacturing. Although the process studied here is not industrially useable as is, it is a step towards processing cheap unprocessed material with a laser beam.

Structural Integrity Assessments for Validating Directed Energy Deposition Repairs of Integrally Bladed Rotor

2020 ◽  
Author(s):  
Onome Scott-Emuakpor ◽  
Brian Runyon ◽  
Tommy George ◽  
Andrew Goldin ◽  
Casey Holycross ◽  
...  
Keyword(s):  
Energy Deposition ◽  
Structural Integrity ◽  
Low Cycle Fatigue ◽  
Cycle Fatigue ◽  
Component Level ◽  
Integrity Assessment ◽  
Repair Processes ◽  
Directed Energy Deposition ◽  
Directed Energy ◽  
Blown Powder

Abstract Considerable steps to assess the structural capability of laser directed energy deposition (DED) aim to determine the viability of repair processes for integrally bladed rotors (IBRs). Two laser DED processes are under investigation in this study: wire fed and blown powder feedstock. Using a small subsonic Titanium 6Al-4V fan as the component of interest, a series of tests and associated models for laboratory specimens, subcomponents, and components are necessary for proper assessment of material structural properties pertaining to the intended mission of the IBR. Experimentation on laboratory specimens acquire properties such as tensile strength, elongation, low cycle fatigue (LCF), high cycle fatigue (HCF), crack growth rate, and fracture toughness. Subcomponent test articles fabrication occurs by sectioning an operational IBR into individual blades for vibration HCF assessment. Component level testing focuses on LCF and overspeed strength acquired from spin rig testing. Even though the full IBR repair validation of laboratory specimen, subcomponent, and component testing has yet to be completed, the results to-date for laser DED repairs are promising. Furthermore, this plan for structural integrity assessment can serve as a reference for validation of future IBR repair processes.

Sign in / Sign up

Export Citation Format

Share Document