scholarly journals Optimizing the Mean and Variance of Bead Geometry in the Wire + Arc Additive Manufacturing Using a Desirability Function Method

2021 ◽  
Author(s):  
Jin-Soo Cho ◽  
Dong-Hee Lee ◽  
Gi-Jeong Seo ◽  
Duck-Bong Kim ◽  
Seung-Jun Shin
Keyword(s):  
Additive Manufacturing ◽  
Function Method ◽  
Desirability Function ◽  
Welding Process ◽  
Economic Losses ◽  
Bead Geometry ◽  
The Mean ◽  
Actual Geometry ◽  
Wire Arc Additive Manufacturing ◽  
Optimal Settings

Abstract Wire + arc additive manufacturing (WAAM) is an arc welding process that uses non-consumable tungsten electrodes to produce the weld. The material used in this study is a titanium, carbon, zirconium, and molybdenum (TZM) alloy that is physically and chemically stable and has good performance for use as a welding and high-temperature heating element. However, the price is higher than that of other materials. Because welding cannot be modified after manufacturing, economic losses are high in the case of a defective product. Therefore, it is important to find the best welding settings for the target bead geometry during welding. In this study, welding experiments are designed based on a central composite design, and single-layer WAAM is performed using a TZM material. Consequently, we obtain 17 beads and measure the height, width, as well as left and right toe angles, which represent the geometry of the beads. Based on the measured geometry, we obtain the optimal settings for the WAAM parameters whereat the mean of each geometry is close to its target value and its variance is minimized by using a desirability function method. Furthermore, we conduct additional experiments to validate the optimal settings that we obtain. We compare the predicted and actual geometry values and find that they are quite close. This result indicates that valid optimal settings for the process parameters can be obtained via the proposed method.

scholarly journals Geometry and Distortion Prediction of Multiple Layers for Wire Arc Additive Manufacturing with Artificial Neural Networks

2021 ◽  
Vol 11 (10) ◽  
pp. 4694
Author(s):  
Christian Wacker ◽  
Markus Köhler ◽  
Martin David ◽  
Franziska Aschersleben ◽  
Felix Gabriel ◽  
...  
Keyword(s):  
Additive Manufacturing ◽  
Welding Process ◽  
High Energy ◽  
Welding Distortion ◽  
Direct Energy Deposition ◽  
Direct Energy ◽  
Industrial Use ◽  
Artificial Neural ◽  
Artificial Neural Network Ann ◽  
Wire Arc Additive Manufacturing

Wire arc additive manufacturing (WAAM) is a direct energy deposition (DED) process with high deposition rates, but deformation and distortion can occur due to the high energy input and resulting strains. Despite great efforts, the prediction of distortion and resulting geometry in additive manufacturing processes using WAAM remains challenging. In this work, an artificial neural network (ANN) is established to predict welding distortion and geometric accuracy for multilayer WAAM structures. For demonstration purposes, the ANN creation process is presented on a smaller scale for multilayer beads on plate welds on a thin substrate sheet. Multiple concepts for the creation of ANNs and the handling of outliers are developed, implemented, and compared. Good results have been achieved by applying an enhanced ANN using deformation and geometry from the previously deposited layer. With further adaptions to this method, a prediction of additive welded structures, geometries, and shapes in defined segments is conceivable, which would enable a multitude of applications for ANNs in the WAAM-Process, especially for applications closer to industrial use cases. It would be feasible to use them as preparatory measures for multi-segmented structures as well as an application during the welding process to continuously adapt parameters for a higher resulting component quality.

Control of humping phenomenon and analyzing mechanical properties of Al–Si wire-arc additive manufacturing fabricated samples using cold metal transfer process

2021 ◽  
pp. 095440622199840
Author(s):  
Yashwant Koli ◽  
N Yuvaraj ◽  
Aravindan Sivanandam ◽  
Vipin
Keyword(s):  
Mechanical Properties ◽  
Additive Manufacturing ◽  
Heat Input ◽  
Large Scale ◽  
High Deposition Rate ◽  
Bead Geometry ◽  
Layer By Layer ◽  
Cold Metal Transfer ◽  
Geometrical Shapes ◽  
Wire Arc Additive Manufacturing

Nowadays, rapid prototyping is an emerging trend that is followed by industries and auto sector on a large scale which produces intricate geometrical shapes for industrial applications. The wire arc additive manufacturing (WAAM) technique produces large scale industrial products which having intricate geometrical shapes, which is fabricated by layer by layer metal deposition. In this paper, the CMT technique is used to fabricate single-walled WAAM samples. CMT has a high deposition rate, lower thermal heat input and high cladding efficiency characteristics. Humping is a common defect encountered in the WAAM method which not only deteriorates the bead geometry/weld aesthetics but also limits the positional capability in the process. Humping defect also plays a vital role in the reduction of hardness and tensile strength of the fabricated WAAM sample. The humping defect can be controlled by using low heat input parameters which ultimately improves the mechanical properties of WAAM samples. Two types of path planning directions namely uni-directional and bi-directional are adopted in this paper. Results show that the optimum WAAM sample can be achieved by adopting a bi-directional strategy and operating with lower heat input process parameters. This avoids both material wastage and humping defect of the fabricated samples.

Wire arc additive manufacturing of Invar parts: bead geometry and melt pool monitoring

Measurement ◽  
2021 ◽  
pp. 110452
Author(s):  
Fernando Veiga ◽  
Alfredo Suarez ◽  
Eider Aldalur ◽  
Teresa Artaza
Keyword(s):  
Additive Manufacturing ◽  
Bead Geometry ◽  
Melt Pool ◽  
Wire Arc Additive Manufacturing

Using Unsupervised Learning for Regulating Deposition Speed During Robotic Wire Arc Additive Manufacturing

2021 ◽  
Author(s):  
Ashish Kulkarni ◽  
Prahar M. Bhatt ◽  
Alec Kanyuck ◽  
Satyandra K. Gupta
Keyword(s):  
Additive Manufacturing ◽  
Unsupervised Learning ◽  
Molten Metal ◽  
Length Variation ◽  
Bead Geometry ◽  
Layer By Layer ◽  
Arc Length ◽  
Regulation Scheme ◽  
Speed Regulation ◽  
Wire Arc Additive Manufacturing

Abstract Robotic Wire Arc Additive Manufacturing (WAAM) is the layer-by-layer deposition of molten metal to build a three-dimensional part. In this process, the fed metal wire is melted using an electric arc as a heat source. The process is sensitive to the arc conditions, such as arc length. While building WAAM parts, the metal beads overlap at corners causing material accumulation. Material accumulation is undesirable as it leads to uneven build height and process failures caused by arc length variation. This paper introduces a deposition speed regulation scheme to avoid the corner accumulation problem and build parts with uniform build height. The regulated speed has a complex relationship with the corner angle, bead geometry, and molten metal dynamics. So we need to train a model that can predict suitable speed regulations for corner angles encountered while building the part. We develop an unsupervised learning technique to characterize the uniformity of the bead profile of a WAAM built layer and check for anomalous bead profiles. We train a model using these results that can predict suitable speed regulation parameters for different corner angles. We test this model by building a WAAM part using our speed regulation scheme and validate if the built part has uniform build height and reduced corner defects.

Mapping of Bead Geometry in Wire Arc Additive Manufacturing Systems Using Passive Vision

2022 ◽  
Author(s):  
Marcus O. Couto ◽  
Arthur G. Rodrigues ◽  
Fernando Coutinho ◽  
Ramon R. Costa ◽  
Antonio C. Leite ◽  
...  
Keyword(s):  
Additive Manufacturing ◽  
Manufacturing Systems ◽  
Bead Geometry ◽  
Wire Arc Additive Manufacturing

scholarly journals Modeling and Optimization of Weld Bead Profile with Varied Welding Stages for Weathering Steel A606

2021 ◽  
Author(s):  
Dawei Zhao ◽  
Yuriy Bezgans ◽  
Nikita Vdonin ◽  
Liudmila Radionova ◽  
Vitaly Bykov
Keyword(s):  
Desirability Function ◽  
Research Work ◽  
Welding Process ◽  
Weld Bead ◽  
Welding Parameters ◽  
Weathering Steel ◽  
Bead Geometry ◽  
Feed Speed ◽  
Geometric Features ◽  
Weld Bead Geometry

Abstract The profile of the welding bead changes with the welding process parameters during the gas metal arc welding (GMAW) process, the reinforcement disappears and the penetration becomes sunken when the excessive welding heat input is applied. However, little research work is specially planned to cope with the studying of welding bead at these stages. A systematic studying of the relationships among the welding process variables and welding bead geometric features and optimization of the welding quality is presented. The influences of the welding technological parameters (voltage, welding speed, and wire feed speed) on the welding geometry were revealed and the models correlating them were established. The features of the weld bead geometry were composed of top reinforcement width, top reinforcement height, penetration depth, bottom reinforcement width, and bottom reinforcement height. By the desirability function approach, the recommendation of suitable welding parameters to meet the contradicting demands of multiple bead geometric features is fulfilled. The microstructure in different welding regions and mechanical performances of the welding joints produced by the verification test were also studied.

scholarly journals Effect of Phase Transformations on Scanning Strategy in WAAM Fabrication

Materials ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 7871
Author(s):  
Muhammad Hassaan Ali ◽  
You Sung Han
Keyword(s):  
Residual Stress ◽  
Additive Manufacturing ◽  
Residual Stresses ◽  
Phase Transformations ◽  
Manufacturing Industry ◽  
Welding Process ◽  
Stress Generation ◽  
Temperature History ◽  
History Of ◽  
Wire Arc Additive Manufacturing

Due to its high production rates and low cost as compared to other metal additive manufacturing processes, wire arc additive manufacturing (WAAM) has become an emerging technology in the manufacturing industry. However, the residual stress generation and part distortion hinder its widespread adoption because of the complex thermal build-histories of WAAM parts. One of the ways to alleviate this problem is to consider the effects of scan strategies as it directly influences the thermal history of the built part. Since WAAM itself is an evolved welding process and even though it is evident from welding studies that phase transformations directly affect the residual stresses in welded parts, it remains unclear how the consideration of phase transformations for different scan strategies will affect the residual stresses and distortions in the WAAMed parts. A FEM study has been performed to elucidate the effects of phase transformations on residual stresses and the distortion for different deposition patterns. The current findings highlight that for the fabrication of low-carbon martensitic steels: The consideration of phase transformations for line-type discontinuous patterns (alternate and raster) do not significantly affect the residual stresses. Consideration of phase transformations significantly affects residual stresses for continuous patterns (zigzag, in–out and out–in). To accurately simulate complex patterns, phase transformations should be considered because the patterns directly influence the temperature history of the built part and will thus affect the phase transformations, the residual stresses and the warpage. During the fabrication of WAAM parts, whenever possible, discontinuous line scanning patterns should be considered as they provide the part with uniform residual stress and distortion. The alternate line pattern has been found to be the most consistent overall pattern.

scholarly journals In Situ Production of Titanium Aluminides during Wire Arc Additive Manufacturing with Hot-Wire Assisted GMAW Process

Metals ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 578 ◽  
Author(s):  
Philipp Henckell ◽  
Yarop Ali ◽  
Andreas Metz ◽  
Jean Pierre Bergmann ◽  
Jan Reimann
Keyword(s):  
Additive Manufacturing ◽  
Titanium Aluminides ◽  
Gas Metal Arc Welding ◽  
Welding Process ◽  
Alloy Formation ◽  
Layer By Layer ◽  
Feeding Rates ◽  
Hot Wire ◽  
Wire Arc Additive Manufacturing

As part of a feasibility study, an alternative production process for titanium aluminides was investigated. This process is based on in situ alloying by means of a multi-wire technique in the layer-wise additive manufacturing process. Thereby, gas metal arc welding (GMAW) was combined with additional hot-wire feeding. By using two separate wires made of titanium and aluminum, it is possible to implement the alloy formation of titanium aluminides directly in the weld bead of the welding process. In this study, wall structures were built layer-by-layer with alloy compositions between 10 at% and 55 at% aluminum by changing the feeding rates. During this investigation, the macroscopic characteristics, microstructural formation, and the change of the microhardness values were analyzed. A close examination of the influence of welding speed and post-process heat treatment on the Ti–47Al alloy was performed; this being particularly relevant due to its economically wide spread applications.

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