scholarly journals Two-dimensional thermal finite element model of directed energy deposition: Matching melt pool temperature profile with pyrometer measurement

2020 ◽  
Vol 57 ◽  
pp. 187-195
Author(s):  
Bohumir Jelinek ◽  
William J. Young ◽  
Matthew Dantin ◽  
William Furr ◽  
Haley Doude ◽  
...  
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Temperature Profile ◽  
Energy Deposition ◽  
Element Model ◽  
Two Dimensional ◽  
Melt Pool ◽  
Directed Energy Deposition ◽  
Melt Pool Temperature ◽  
Directed Energy

scholarly journals Estimation Method of Interpass Time for the Control of Temperature during a Directed Energy Deposition Process of a Ti–6Al–4V Planar Layer

Materials ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 4935
Author(s):  
Bih-Lii Chua ◽  
Dong-Gyu Ahn
Keyword(s):  
Finite Element ◽  
Energy Deposition ◽  
Element Model ◽  
Planar Layer ◽  
Melt Pool ◽  
Feeding Type ◽  
Interpass Time ◽  
Wire Feeding ◽  
Directed Energy ◽  
Interpass Temperature

Directed energy deposition (DED) provides a promising additive manufacturing method to fabricate and repair large metallic parts. However, it may suffer from excessive heat accumulation due to a high build rate, particularly during a wire feeding-type DED process. The implementation of interpass time in between two depositions of beads plays an important process role to passively control the interpass temperature. In this study, a method to estimate the proper interpass time using regression analysis from heat transfer finite element analysis is proposed for maintaining the interpass temperature during a wire feeding-type DED deposition of a planar layer. The overlapping beads of a planar layer are estimated using a polygonal-shaped bead profile in the finite element model. From the estimated proper interpass time, a selected proper interpass time scheme (PITS) is suggested for practical implementation. The selected PITS is applied in a thermo-mechanical finite element model to evaluate the temperature distribution and its effects on the depth of the melt pool, the depth of the heat-affected zone (HAZ), displacement, and residual stresses. By comparing the predicted results with those using a constant interpass time scheme (CITS), the selected PITS shows better control in reducing the depths of the melt pool and HAZ without severely inducing large displacement and residual stresses.

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
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