Melt pool temperature modeling and control for Laser Metal 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.

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

Journal of Manufacturing Science and Engineering ◽

10.1115/1.4000883 ◽

2010 ◽

Vol 132 (1) ◽

Cited By ~ 15

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.

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

Materials ◽

10.3390/ma11081388 ◽

2018 ◽

Vol 11 (8) ◽

pp. 1388 ◽

Cited By ~ 11

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.

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Frequency Domain Uncertainty Modeling and Quantification of the Laser Metal Deposition Process

Volume 2: Mechatronics; Mechatronics and Controls in Advanced Manufacturing; Modeling and Control of Automotive Systems and Combustion Engines; Modeling and Validation; Motion and Vibration Control Applications; Multi-Agent and Networked Systems; Path Planning and Motion Control; Robot Manipulators; Sensors and Actuators; Tracking Control Systems; Uncertain Systems and Robustness; Unmanned, Ground and Surface Robotics; Vehicle Dynamic Controls; Vehicle Dynamics and Traffic Control ◽

10.1115/dscc2016-9777 ◽

2016 ◽

Author(s):

Patrick M. Sammons ◽

Douglas A. Bristow ◽

Robert G. Landers

Keyword(s):

Frequency Domain ◽

Uncertainty Modeling ◽

Deposition Process ◽

Metal Deposition ◽

Great Promise ◽

Laser Metal Deposition ◽

Modeling And Control ◽

Metal Parts ◽

Modeling Uncertainties ◽

And Control

Additive Manufacturing (AM) is a growing class of manufacturing processes where parts are fabricated by repeated addition of material. Many of these processes show great promise for the production of complex, functional parts for use in critical applications. One such process, Laser Metal Deposition (LMD), uses a laser and a coaxial blown metal powder source to produce functional metal parts. However, it has been demonstrated that the LMD process possesses complex two-dimensional dynamics which, when not appropriately accounted for in the modeling and control stages, can lead to build failures. Additionally, even when the two-dimensionality of the process is accounted for, modeling and process uncertainties can lead to degraded performance or instability. Here, in the context of a control oriented model of the LMD process developed previously, process and modeling uncertainties are modeled and quantified in the frequency domain.

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Spectroscopic monitoring and melt pool temperature estimation during the laser metal deposition process

Journal of Laser Applications ◽

10.2351/1.4943995 ◽

2016 ◽

Vol 28 (2) ◽

pp. 022303 ◽

Cited By ~ 5

Author(s):

Dieter De Baere ◽

Wim Devesse ◽

Ben De Pauw ◽

Lien Smeesters ◽

Hugo Thienpont ◽

...

Keyword(s):

Deposition Process ◽

Metal Deposition ◽

Laser Metal Deposition ◽

Temperature Estimation ◽

Spectroscopic Monitoring ◽

Melt Pool ◽

Melt Pool Temperature

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Laser metal deposition controlling: melt pool temperature and target / actual height difference monitoring

Procedia CIRP ◽

10.1016/j.procir.2020.09.161 ◽

2020 ◽

Vol 94 ◽

pp. 441-444

Author(s):

Magnus Thiele ◽

David Dillkötter ◽

Johann Stoppok ◽

Martin Mönnigmann ◽

Cemal Esen

Keyword(s):

Metal Deposition ◽

Laser Metal Deposition ◽

Height Difference ◽

Melt Pool ◽

Melt Pool Temperature ◽

Actual Height

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A Multi-Physics Way to Investigate some Aspects of Melt Pool During Laser Substrate Interaction in Laser Metal Deposition Process

Transactions of the Indian Institute of Metals ◽

10.1007/s12666-021-02364-w ◽

2021 ◽

Author(s):

Piyush Pant ◽

Dipankar Chatterjee

Keyword(s):

Deposition Process ◽

Metal Deposition ◽

Laser Metal Deposition ◽

Substrate Interaction ◽

Melt Pool

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Variable Powder Flow Rate Control in Laser Metal Deposition Processes

ASME 2008 Dynamic Systems and Control Conference, Parts A and B ◽

10.1115/dscc2008-2112 ◽

2008 ◽

Author(s):

Lie Tang ◽

Jianzhong Ruan ◽

Robert G. Landers ◽

Frank Liou

Keyword(s):

Transport System ◽

Flow Rate ◽

Rate Control ◽

Metal Deposition ◽

Powder Flow ◽

Laser Metal Deposition ◽

Motion System ◽

Powder Flow Rate ◽

Deposition Processes ◽

Flow Rate Control

This paper proposes a novel method, called Variable Powder Flow Rate Control (VPFRC), for the regulation of powder flow rate in laser metal deposition processes. The idea of VPFRC is to adjust the powder flow rate to maintain a uniform powder deposition per unit length even when disturbances occur (e.g., the motion system accelerates and decelerates). Dynamic models of the powder delivery system motor and the powder transport system (i.e., five–meter pipe, powder dispenser, and cladding head) are constructed. A general tracking controller is then designed to track variable powder flow rate references. Since the powder flow rate at the nozzle exit cannot be directly measured, it is estimated using the powder transport system model. The input to this model is the DC motor rotation speed, which is estimated on–line using a Kalman filter. Experiments are conducted to examine the performance of the proposed control methodology. The experimental results demonstrate that the VPFRC method is successful in maintaining a uniform track morphology, even when the motion system accelerates and decelerates.

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