Optimal laser power command generation for direct energy deposition by applying gradient descent to a thermal conductivity simulation

Purpose Direct energy deposition (DED) is an additive manufacturing process that allows to produce metal parts with complex shapes. DED process depends on several parameters, including laser power, deposition rate and powder feeding rate. It is important to control the manufacturing process to study the influence of the operating parameters on the final characteristics of these parts and to optimize them. Computational modeling helps engineers to address these challenges. This paper aims to establish a framework for the development, verification and application of meshless methods and surrogate models to the DED process. Design/methodology/approach Finite pointset method (FPM) is used to solve conservation equations involved in the DED process. A surrogate model is then established for the DED process using design of experiments with powder feeding rate, laser power and scanning speed as input parameters. The surrogate model is constructed using neutral networks (NN) approximations for the prediction of maximum temperature, clad angle and dilution. Findings The simulations of thin wall built of Ti-6Al-4V titanium alloy clearly demonstrated that FPM simulation is successful in predicting temperature distribution for different process conditions and compare favorably with experimental results from the literature. A methodology has been developed for obtaining a surrogate model for DED process. Originality/value This methodology shows how to achieve realistic simulations of DED process and how to construct a surrogate model for further use in optimization loop.

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Effect of laser power and powder feed rate on interfacial crack and mechanical/microstructural characterizations in repairing of 630 stainless steel using direct energy deposition

Materials Science and Engineering A ◽

10.1016/j.msea.2021.142004 ◽

2021 ◽

pp. 142004

Author(s):

Tae Geon Kim ◽

Do Sik Shim

Keyword(s):

Stainless Steel ◽

Feed Rate ◽

Laser Power ◽

Energy Deposition ◽

Interfacial Crack ◽

Powder Feed Rate ◽

Direct Energy Deposition ◽

Powder Feed ◽

Direct Energy

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A Study on the Influence of Laser Power on the Microstructure and Mechanical Properties of Functionally Graded Materials Produced by Direct Energy Deposition

Korean Journal of Metals and Materials ◽

10.3365/kjmm.2020.58.11.782 ◽

2020 ◽

Vol 58 (11) ◽

pp. 782-792

Author(s):

Giseung Shin ◽

Ji hyun Yoon ◽

Dae Whan Kim ◽

Yongho Park ◽

Jeoung Han Kim

Keyword(s):

Mechanical Properties ◽

Laser Power ◽

Energy Deposition ◽

Deposition Process ◽

Functionally Graded ◽

Direct Energy Deposition ◽

Microstructure And Mechanical Properties ◽

Type 316L ◽

Direct Energy ◽

Small Change

This study investigated the effects of laser power on the microstructure and mechanical properties of functionally gradient materials (FGM) produced by direct energy deposition. The FGM consisted of five different layers, which were a mixture of austenitic stainless steel (Type 316L) and ferritic steel (HSLA). During the direct energy deposition, two different laser power conditions (450W and 380W) were used. The ratio of Type 316L and HSAL at each deposition layers were 100:0, 65:35, 50:50, 25:75, and 0:100. After the direct energy deposition process, no cracks or delamination were seen between layers of the FGM. The effects of laser power on chemical composition and microstructure were not significant. However, as the laser power decreased, tensile strength and elongation changed with a small change in grain size.

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