Direct metal deposition melt pool temperature distribution control through novel holographic beam shaping, allowing improved mechanical and corrosion properties

2009 ◽  
Author(s):  
Matthew Gibson ◽  
John Tyrer ◽  
Rebecca Higginson
Keyword(s):  
Temperature Distribution ◽  
Beam Shaping ◽  
Metal Deposition ◽  
Direct Metal Deposition ◽  
Corrosion Properties ◽  
Melt Pool ◽  
Melt Pool Temperature ◽  
Mechanical And Corrosion Properties

scholarly journals Study of the Influence of Shielding Gases on Laser Metal Deposition of Inconel 718 Superalloy

Materials ◽  
2018 ◽  
Vol 11 (8) ◽  
pp. 1388 ◽  
Author(s):  
Jose Ruiz ◽  
Magdalena Cortina ◽  
Jon Arrizubieta ◽  
Aitzol Lamikiz
Keyword(s):  
Metal Deposition ◽  
Slight Reduction ◽  
Laser Metal Deposition ◽  
Melt Pool ◽  
Industrial Sectors ◽  
Inconel 718 Superalloy ◽  
Melt Pool Temperature ◽  
Different Gases ◽  
Die And Mold

The use of the Laser Metal Deposition (LMD) technology as a manufacturing and repairing technique in industrial sectors like the die and mold and aerospace is increasing within the last decades. Research carried out in the field of LMD process situates argon as the most usual inert gas, followed by nitrogen. Some leading companies have started to use helium and argon as carrier and shielding gas, respectively. There is therefore a pressing need to know how the use of different gases may affect the LMD process due there being a lack of knowledge with regard to gas mixtures. The aim of the present work is to evaluate the influence of a mixture of argon and helium on the LMD process by analyzing single tracks of deposited material. For this purpose, special attention is paid to the melt pool temperature, as well as to the characterization of the deposited clads. The increment of helium concentration in the gases of the LMD processes based on argon will have three effects. The first one is a slight reduction of the height of the clads. Second, an increase of the temperature of the melt pool. Last, smaller wet angles are obtained for higher helium concentrations.

Surface Finish Issues after Direct Metal Deposition

2012 ◽  
Vol 706-709 ◽  
pp. 228-233 ◽  
Author(s):  
P. Peyre ◽  
M. Gharbi ◽  
C. Gorny ◽  
M. Carin ◽  
S. Morville ◽  
...  
Keyword(s):  
Surface Finish ◽  
Experimental Tests ◽  
Metal Deposition ◽  
Direct Metal Deposition ◽  
Physical Mechanisms ◽  
Melt Pool ◽  
3D Profilometry ◽  
Surface Finishes ◽  
3D Shapes

Derived from laser cladding, the Direct Metal Deposition (DMD) laser process, is based upon a laser beam – projected powder interaction, and allows manufacturing complex 3D shapes much faster than conventional processes. However, the surface finish remains critical, and DMD parts usually necessitate post-machining steps. In this context, the focus of our work was: (1) to understand the physical mechanisms responsible for deleterious surface finishes, (2) to propose different experimental solutions for improving surface finish. Our experimental approach is based upon: (1) adequate modifications of the DMD conditions (gas shielding, laser conditions, coaxial or off-axis nozzles), (2) a characterization of laser-powder-melt-pool interactions using fast camera analysis, (3) a precise check of surface aspects using 3D profilometry, SEM, (4) preliminary thermo-convective simulations to understand melt-pool hydrodynamics. Most of the experimental tests were carried out on a Ti6Al4V titanium alloy, widely investigated already. Results confirm that surface degradation depends on two aspects: the sticking of non-melted or partially melted particles on the free surfaces, and the formation of menisci with more or less pronounced curvature radii. Among other aspects, a reduction of layer thickness and an increase of melt-pool volumes to favor re-melting processes are shown to have a beneficial effect on roughness parameters.

Thermal Analysis and Verification for Direct Metal Deposition of 0Cr18Ni9 Stainless Steel

2019 ◽  
Author(s):  
Jin Wang ◽  
Jing Shi ◽  
Yi Wang ◽  
Yun Bai
Keyword(s):  
Stainless Steel ◽  
Additive Manufacturing ◽  
Temperature Distribution ◽  
Process Parameters ◽  
Thermal Stresses ◽  
Infrared Camera ◽  
Dimensional Accuracy ◽  
Metal Deposition ◽  
Direct Metal Deposition ◽  
Heating And Cooling

Abstract Due to rapid cyclic heating and cooling in metal additive manufacturing processes, such as selective laser melting (SLM) and direct metal deposition (DMD), large thermal stresses will form and this may lead to the loss of dimensional accuracy or even cracks. The integration of numerical analysis and experimental validation provides a powerful tool that allows the prediction of defects, and optimization of the component design and the additive manufacturing process parameters. In this work, a numerical simulation on the thermal process of DMD of 0Cr18Ni9 stainless steel is conducted. The simulation is based on the finite volume method (FVM). An in-house code is developed, and it is able to calculate the temperature distribution dynamically. The model size is 30mm × 30mm × 10.5mm, containing 432,000 cells. A DMD experiment on the material with the same configuration and process parameters is also carried out, during which an infrared camera is adopted to obtain the surface temperature distribution continuously, and thermocouples are embedded in the baseplate to record the temperature histories. It is found that the numerical results agree with the experimental results well.

An analytical model of the melt pool and single track in coaxial laser direct metal deposition (LDMD) additive manufacturing

2017 ◽  
Vol 02 (04) ◽  
pp. 1750013 ◽  
Author(s):  
Jian Liu ◽  
Erica Stevens ◽  
Qingchen Yang ◽  
Markus Chmielus ◽  
Albert C. To
Keyword(s):  
Analytical Model ◽  
Interaction Model ◽  
Source Model ◽  
Metal Deposition ◽  
Direct Metal Deposition ◽  
Single Track ◽  
Gaussian Laser Beam ◽  
Track Geometry ◽  
Geometry Model ◽  
Melt Pool

An analytical model was developed for the melt pool and single scan track geometry as a function of process parameters. For computational efficiency, the developed model has simple mathematical forms with essential physics taken into account, without the need for complicated numerical simulation. In this research, a non-diverging Gaussian laser beam and coaxial diverging Gaussian powder stream combination is used to represent the coaxial laser direct metal deposition (LDMD) process. Analytical laser-powder interaction model is used to obtain the distribution of attenuated laser intensity and temperature of heated powders at the substrate. On the substrate, the melt pool is calculated by integrating Rosenthal's point heat source model. An iterative procedure is used to ensure the mass–energy balances and to calculate the melt pool and catchment efficiency. By assuming that the assimilated powder will reshape due to surface tension before solidification, a simple clad geometry model is established. The proposed model is used to simulate the geometry of single track depositions of Ti6Al4V, which shows a good agreement between model prediction and experimental results. This work demonstrates that the developed model has the potential to be used to narrow the parameter space for process optimization.

Melt Pool Temperature Control for Laser Metal Deposition Processes—Part I: Online Temperature Control

2010 ◽  
Vol 132 (1) ◽  
Author(s):  
Lie Tang ◽  
Robert G. Landers
Keyword(s):  
Temperature Control ◽  
Process Parameters ◽  
Process Model ◽  
Dynamic Balance ◽  
Metal Deposition ◽  
Time Varying ◽  
Laser Metal Deposition ◽  
Melt Pool ◽  
Melt Pool Temperature ◽  
Deposition Processes

Melt pool temperature is of great importance to deposition quality in laser metal deposition processes. To control the melt pool temperature, an empirical process model describing the relationship between the temperature and process parameters (i.e., laser power, powder flow rate, and traverse speed) is established and verified experimentally. A general tracking controller using the internal model principle is then designed. To examine the controller performance, three sets of experiments tracking both constant and time-varying temperature references are conducted. The results show the melt pool temperature controller performs well in tracking both constant and time-varying temperature references even when process parameters vary significantly. However a multilayer deposition experiment illustrates that maintaining a constant melt pool temperature does not necessarily lead to uniform track morphology, which is an important criteria for deposition quality. The reason is believed to be that different melt pool morphologies may have the same temperature depending on the dynamic balance of heat input and heat loss.

Melt Pool Temperature Control for Laser Metal Deposition Processes—Part II: Layer-to-Layer Temperature Control

2010 ◽  
Vol 132 (1) ◽  
Author(s):  
Lie Tang ◽  
Robert G. Landers
Keyword(s):  
Temperature Control ◽  
Heat Input ◽  
Laser Power ◽  
Process Model ◽  
Metal Deposition ◽  
Laser Metal Deposition ◽  
Melt Pool ◽  
Power Profile ◽  
Melt Pool Temperature ◽  
Deposition Processes

Heat input regulation is crucial for deposition quality in laser metal deposition (LMD) processes. To control the heat input, melt pool temperature is regulated using temperature controllers. Part I of this paper showed that, although online melt pool temperature control performs well in terms of tracking the temperature reference, it cannot guarantee consistent track morphology. Therefore, a new methodology, known as layer-to-layer temperature control, is proposed in this paper. The idea of layer-to-layer temperature control is to adjust the laser power profile between layers. The part height profile is measured between layers, and the temperature is measured online. The data are then utilized to identify the parameters of a LMD process model using particle swarm optimization. The laser power profile is then computed using iterative learning control, based on the estimated process model and the reference melt pool temperature of the next layer. The deposition results show that the layer-to-layer temperature controller is capable of not only tracking the reference temperature, but also producing a consistent track morphology.

Melt pool evolution on inclined NV E690 steel plates during laser direct metal deposition

2021 ◽  
Vol 136 ◽  
pp. 106745
Author(s):  
Mingzhi Chen ◽  
Yi Lu ◽  
Zhandong Wang ◽  
Huifang Lan ◽  
Guifang Sun ◽  
...  
Keyword(s):  
Metal Deposition ◽  
Direct Metal Deposition ◽  
Steel Plates ◽  
Melt Pool
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