scholarly journals Influence of Adapted Wavelengths on Temperature Fields and Melt Pool Geometry in Laser Transmission Welding

2016 ◽  
Vol 83 ◽  
pp. 1055-1063 ◽  
Author(s):  
A. Schkutow ◽  
T. Frick
Keyword(s):  
Temperature Fields ◽  
Laser Transmission Welding ◽  
Melt Pool

Laser transmission welding with part adapted temperature fields

2012 ◽  
Author(s):  
Martin Devrient ◽  
Verena Wippo ◽  
Peter Jaeschke ◽  
Uwe Stute ◽  
Thomas Frick ◽  
...  
Keyword(s):  
Temperature Fields ◽  
Laser Transmission Welding

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 Experimental Investigation of Laser Transmission Welding of Thermoplastics with Part-Adapted Temperature Fields

2013 ◽  
Vol 41 ◽  
pp. 59-69 ◽  
Author(s):  
M. Devrient ◽  
M. Kern ◽  
P. Jaeschke ◽  
U. Stute ◽  
H. Haferkamp ◽  
...  
Keyword(s):  
Experimental Investigation ◽  
Temperature Fields ◽  
Laser Transmission Welding

Morphological Analysis of 316L Laser Powder Bed Fusion Melt-Pool via the Enriched Analytical Solution Method

2020 ◽  
Author(s):  
J. G. Michopoulos ◽  
J. C. Steuben ◽  
A. J. Birnbaum ◽  
A. P. Iliopoulos ◽  
J. Aroh ◽  
...  
Keyword(s):  
Analytical Solution ◽  
High Speed ◽  
Solution Method ◽  
Morphological Characteristics ◽  
Temperature Fields ◽  
Powder Bed Fusion ◽  
Laser Powder Bed Fusion ◽  
Powder Bed ◽  
Melt Pool ◽  
Spatio Temporal

Abstract The recent development of the Enriched Analytical Solution Method (EASM) for evaluating the spatio-temporal distribution of the temperature fields generated during the Laser Powder Bed Fusion (LPBF) Additive Manufacturing (AM) processes is provides an opportunity to study the sensitivity of the morphological parameters characterizing the associated melt-pools as a function of process parameters. The present work exercises the EASM for the case of a single-path trace over a 316L base plate under LPBF heat deposition conditions. To assist in the evaluation of solidification parameters, the spatial derivatives of the EASM are also derived. A process parameter subspace spanned by the scan velocity and the laser power is considered and the EASM is utilized for deriving a number of geometrical morphological characteristics of the melt pool as well as the quantities controlling the evolution of the solidification front. Finally, comparisons with initial experimental results obtained by in-situ high speed synchrotron X-ray imaging, capturing the spatio-temporal evolution of the melt pool profile are also presented.

Transient Temperature Field Analysis in Laser Cladding Processing

2012 ◽  
Vol 538-541 ◽  
pp. 1874-1877 ◽  
Author(s):  
Shuai Zhang ◽  
Yan Ling Tian ◽  
Fu Jun Wang
Keyword(s):  
Laser Cladding ◽  
Scanning Speed ◽  
Processing Parameters ◽  
Field Analysis ◽  
Temperature Fields ◽  
Transient Temperature ◽  
3 Dimensional ◽  
Melt Pool ◽  
Transient Temperature Field ◽  
Temperature Filed

A 3-dimensional (3D) thermal distribution computational methodology for laser cladding is presented. Based on the developed model, which considers the latent heat and change of conductivity in different phase, the transient temperature fields for the preplaced laser cladding processing are performed. The effect of processing parameters including laser power, scanning speed and laser spot diameter on melt pool temperature filed was extensively discussed and some conclusions were drawn.

scholarly journals Effects of Scan Strategy on Thermal Properties and Temperature Field in Selective Laser Melting

2019 ◽  
Author(s):  
Elham Mirkoohi ◽  
Daniel E. Sievers ◽  
Hamid Garmestani ◽  
Steven Y. Liang
Keyword(s):  
Temperature Field ◽  
Additive Manufacturing ◽  
Heat Affected Zone ◽  
Material Properties ◽  
Temperature Fields ◽  
Analytical Models ◽  
Temperature History ◽  
Process Conditions ◽  
Repeated Heating ◽  
Melt Pool

Temperature field is an essential attribute of metal additive manufacturing in view of its bearings on the prediction, control, and optimization of residual stress, part distortion, fatigue, balling effect, etc. This work provides an analytical physics-based approach to investigate the effect of scan strategy parameters including time delay between two irradiations and hatching space on thermal material properties and melt pool geometry. This approach is performed through the analysis of the distribution of material properties and temperature profile in three-dimensional space. The moving point heat source approach is used to predict the temperature field. To predict the temperature field during the additive manufacturing process some important phenomena are considered. 1) Due to the high magnitude of temperature in the presence of the laser, the temperature gradient is usually high which has a crucial influence on thermal material properties. Consequently, the thermal material properties of stainless steel grade 316L are considered to be temperature-dependent. 2) Due to the repeated heating and cooling, part usually undergoes several melting and solidification cycles. This physical phenomenon is considered by modifying the heat capacity using the latent heat of melting. 3) The multi-layer aspect of metal AM process is considered by incorporating the temperature history from the previous layer since the interaction of the successive layers has an impact on heat transfer mechanisms. 4) Effect of heat affected zone on thermal material properties is considered by the superposition of material properties in regions where the temperature fields of two consecutive irradiations have an overlap since the consecutive irradiations change the behavior of the material properties. The goals are to 1) investigate the effects of temperature-sensitive material properties and constant material properties on the temperature field. 2) Study the behavior of thermal material properties under different scan strategies. 3) Study the importance of considering the effect of heat affected zone on thermal material through the prediction of melt pool geometry. 4) Investigate the effect of hatching space on melt pool geometry. This work is purely employed physics-based analytical models to predict the behavior of material properties and temperature field under different process conditions, and no finite element modeling is used.

The development of temperature fields and powder flow during laser direct metal deposition wall growth

2004 ◽  
Vol 218 (5) ◽  
pp. 531-541 ◽  
Author(s):  
A J Pinkerton ◽  
L Li
Keyword(s):  
Flow Model ◽  
Three Dimensional ◽  
Flow Characteristics ◽  
Metal Deposition ◽  
Direct Metal Deposition ◽  
Temperature Fields ◽  
Powder Flow ◽  
Powder Concentration ◽  
Melt Pool ◽  
Temperature Distributions

The additive manufacturing technique of laser direct metal deposition (DMD) has had an impact in rapid prototyping, tooling and small-volume manufacturing applications. Components are built from metallic materials that are deposited by the continuous injection of powder into a moving melt pool, created by a defocused laser beam. The size of the melt pool, the temperature distributions around it and the powder flux are critical in determining process characteristics such as deposition rate. In this paper, the effects that changes in the distance between the laser deposition head and the melt pool have on these factors as a part is built using a coaxial powder feeding system are considered via a two-part analytical model. A heat flow model considers three-dimensional temperature distributions due to a moving Gaussian heat source in a finite volume and a simple mass-flow model considers changes in powder concentration with distance from the deposition head. The model demonstrates the effect of adjusting the melt pool standoff in different ways on melt pool and powder flow characteristics as a DMD structure is built, and hence allows the effect on build rate to be predicted. Its validity is verified by comparison with a series of 316L stainless steel walls, built using different standoff adjustment methods. The model is found to be able to explain the dimensional characteristics found.

The growth of mica polytypes as studied by conventional and high-resolution TEM

1983 ◽  
Vol 41 ◽  
pp. 174-177
Author(s):  
A. Baronnet ◽  
M. Amouric
Keyword(s):  
Water Pressure ◽  
Point Of View ◽  
Temperature Fields ◽  
Natural Occurrence ◽  
Growth Mechanisms ◽  
Long Period ◽  
High Resolution Tem ◽  
Layer Stacking ◽  
Experimental Works ◽  
Potential Use

The origin of mica polytypes has long been a challenging problem for crystal- lographers, mineralogists and petrologists. From the petrological point of view, interest in this field arose from the potential use of layer stacking data to furnish further informations about equilibrium and/or kinetic conditions prevailing during the crystallization of the widespread mica-bearing rocks. From the compilation of previous experimental works dealing with the occurrence domains of the various mica "polymorphs" (1Mr, 1M, 2M1, 2M2 and 3T) within water-pressure vs temperature fields, it became clear that most of these modifications should be considered as metastable for a fixed mica species. Furthermore, the natural occurrence of long-period (or complex) polytypes could not be accounted for by phase considerations. This highlighted the need of a more detailed kinetic approach of the problem and, in particular, of the role growth mechanisms of basal faces could play in this crystallographic phenomenon.

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