Twin-wire welding based additive manufacturing (TWAM): manufacture of functionally gradient objects

2017 ◽  
Vol 23 (5) ◽  
pp. 858-868 ◽  
Author(s):  
Somashekara M. Adinarayanappa ◽  
Suryakumar Simhambhatla
Keyword(s):  
Additive Manufacturing ◽  
Gas Metal Arc Welding ◽  
Filler Wire ◽  
Content Type ◽  
Functionally Gradient ◽  
Metal Arc Welding ◽  
Study Methodology ◽  
The Individual ◽  
Hardness Gradient ◽  
Suitable Process

Purpose Twin-wire welding-based additive manufacturing (TWAM) is a unique process which uses gas metal arc welding (GMAW)-based twin-wire weld-deposition to create functionally gradient materials (FGMs). Presented study aims to focus on creating metallic objects with a hardness gradient using GMAW of twin-wire weld deposition setup. Design/methodology/approach By using dissimilar filler wires in twin-wire weld-deposition, it is possible to create metallic objects with varying hardness. This is made possible by individually controlling the proportion of each filler wire used. ER70S-6 and ER110S-G are the two filler wires used for the study; the former has lower hardness than the latter. In the current study, methodology and various experiments carried out to identify the suitable process parameters at a given location for a desired variation of hardness have been presented. A predictive model for obtaining the wire speed of the filler wires required for a desired value of hardness was also created. Subsequently, sample parts with gradient in various directions have been fabricated. Findings For dissimilar twin-wire weld-deposition used here, it is observed that the resultant hardness is in the volumetric proportion of the hardness of the individual filler wires. This aids the fabrication of FGMs using arc based weld-deposition with localized control of hardness, achieved through the control of the ratio of wire speeds of the individual filler wires. Four sample parts were fabricated to demonstrate the concept of realizing FGMs through TWAM. The fabricated parts showed good match with the desired hardness variation. Research limitations/implications This paper successfully presents the capability of TWAM for creating gradient metallic objects with varying hardness. Although developed using ER70S-6 and ER110S-G filler wire combination, the methodology can be extended for other filler wire combinations too for creating FGMs Originality/value GMAW-based twin-wire welding for additive manufacturing is a novel process which uses dissimilar filler wires for creating FGMs. This paper describes methodology of the same followed by illustration of parts created with bi-directional hardness gradient.

scholarly journals How misconduct in business contributes to understanding the supply side of corruption in international business

2019 ◽  
Vol 16 (3) ◽  
pp. 209-231
Author(s):  
Myriam Ertz ◽  
Fahri Karakas ◽  
Frederick Stapenhurst ◽  
Rasheed Draman ◽  
Emine Sarigöllü ◽  
...  
Keyword(s):  
Multinational Corporations ◽  
International Business ◽  
Supply Side ◽  
Case Study Methodology ◽  
Content Type ◽  
Societal Context ◽  
Study Methodology ◽  
The Individual ◽  
Depth Interviews

Purpose This study aims to offer a better understanding of supply side of bribery and corruption in an international business perspective by conceptualizing it in the narrower concept of misconduct in business (MIB) derived from the deontological perspective to business ethics. Design/methodology/approach The authors use a case study methodology of professionals working within Canadian mining multinational corporations operating in Africa. The authors conducted 2 focus groups, 25 in-depth interviews, document search and an open-ended questionnaire to 15 professionals. Further, they drew on a combination of the classic relationalist sociological framework and its recent revision, that they named the relationalism-substantialism framework to analyze the data. Findings The triangulated empirical data show that the reason why MIB in the form of bribery supply occurs is not exclusively tied to any given perspective, whether the individual, the organization or the wider societal context. Rather, these different layers are tightly intertwined and interact with each other for the supply of bribery to occur. Originality/value Although the three siloed perspectives of MIB have been studied in the literature, they have not been addressed in relation to one another, and even less with a relationalism-substantialism framework. Yet, this perspective contributes compellingly to the understanding of the supply side in bribery. The authors propose a net of conceptually related constructs that intervene in the process of bribery supply occurrence, namely relationality influenced by institutional dysfunctionality and conflation and substantiality through agency and culture.

scholarly journals Investigation of Welds and Heat Affected Zones in Weld Surfacing Steel Plates Taking into Account the Bead Sequence

Materials ◽  
2020 ◽  
Vol 13 (24) ◽  
pp. 5666
Author(s):  
Miloš Mičian ◽  
Jerzy Winczek ◽  
Marek Gucwa ◽  
Radoslav Koňár ◽  
Miloslav Málek ◽  
...  
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Arc Welding ◽  
Gas Metal Arc Welding ◽  
Steel Plates ◽  
Structural Components ◽  
Maximum Hardness ◽  
Qualitative And Quantitative ◽  
Metal Arc Welding ◽  
The Individual

In this paper, the experimental investigation results of the bead sequence input on geometry, structure, and hardness of surfaced layers after multi-pass weld surfacing are analyzed. Three S355 steel plates surfaced by GMAW (Gas Metal Arc Welding) were tested with three different combinations of six beads. The geometric, structural, and hardness analysis was carried out in the cross-section of the plates in the middle of the welded layers. The dimensions of padded layers, fusion and heat-affected zone, as well as the individual padded weld were evaluated. On the basis of metallographic samples, qualitative and quantitative structure analysis was performed. Hardness measurements in surfacing welds and heat-affected zones in the tested cross-sections of the surfacing layers were carried out. A comparative analysis of structure and hardness, taking into account the thermal implications of the bead sequence, allowed for the formulation of conclusions. Comparative studies have shown differences in properties between heat-affected zones (HAZ) for individual surfacing sequences. These differences were mainly in the dimensions of the surfacing layers, the share of structural components, as well as the uniformity of hardness distributions. Finally, the most favorable sequence in terms of structure and hardness distribution, maximum hardness, and range of hardness has been indicated.

scholarly journals Analysis of the Wall Geometry with Different Strategies for High Deposition Wire Arc Additive Manufacturing of Mild Steel

Metals ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 892 ◽  
Author(s):  
Eider Aldalur ◽  
Fernando Veiga ◽  
Alfredo Suárez ◽  
Jon Bilbao ◽  
Aitzol Lamikiz
Keyword(s):  
Additive Manufacturing ◽  
Gas Metal Arc Welding ◽  
Low Carbon Steel ◽  
Utilization Rate ◽  
High Deposition Rate ◽  
Low Carbon ◽  
Metal Arc Welding ◽  
Geometric Precision ◽  
Directed Energy ◽  
Wire Arc Additive Manufacturing

Additive manufacturing has gained relevance in recent decades as an alternative to the manufacture of metal parts. Among the additive technologies, those that are classified as Directed Energy Deposition (DED) are characterized by their high deposition rate, noticeably, Wire Arc Additive Manufacturing (WAAM). However, having the inability to produce parts with acceptable final surface quality and high geometric precision is to be considered an important disadvantage in this process. In this paper, different torch trajectory strategies (oscillatory motion and overlap) in the fabrication of low carbon steel walls will be compared using Gas Metal Arc Welding (GMAW)-based WAAM technology. The comparison is done with a study of the mechanical and microstructural characteristics of the produced walls and finally, addressing the productivity obtained utilizing each strategy. The oscillation strategy shows better results, regarding the utilization rate of deposited material and the flatness of the upper surface, this being advantageous for subsequent machining steps.

scholarly journals Wire Arc Additive Manufacturing (WAAM) of Aluminum Alloy AlMg5Mn with Energy-Reduced Gas Metal Arc Welding (GMAW)

Materials ◽  
2020 ◽  
Vol 13 (12) ◽  
pp. 2671 ◽  
Author(s):  
Maximilian Gierth ◽  
Philipp Henckell ◽  
Yarop Ali ◽  
Jonas Scholl ◽  
Jean Pierre Bergmann
Keyword(s):  
Mechanical Properties ◽  
Additive Manufacturing ◽  
Arc Welding ◽  
Energy Input ◽  
Large Scale ◽  
Unit Length ◽  
Gas Metal Arc Welding ◽  
Cold Metal Transfer ◽  
Metal Arc Welding ◽  
Wire Arc Additive Manufacturing

Large-scale aluminum parts are used in aerospace and automotive industries, due to excellent strength, light weight, and the good corrosion resistance of the material. Additive manufacturing processes enable both cost and time savings in the context of component manufacturing. Thereby, wire arc additive manufacturing (WAAM) is particularly suitable for the production of large volume parts due to deposition rates in the range of kilograms per hour. Challenges during the manufacturing process of aluminum alloys, such as porosity or poor mechanical properties, can be overcome by using arc technologies with adaptable energy input. In this study, WAAM of AlMg5Mn alloy was systematically investigated by using the gas metal arc welding (GMAW) process. Herein, correlations between the energy input and the resulting temperature–time-regimes show the effect on resulting microstructure, weld seam irregularities and the mechanical properties of additively manufactured aluminum parts. Therefore, multilayer walls were built layer wise using the cold metal transfer (CMT) process including conventional CMT, CMT advanced and CMT pulse advanced arc modes. These processing strategies were analyzed by means of energy input, whereby the geometrical features of the layers could be controlled as well as the porosity to area portion to below 1% in the WAAM parts. Furthermore, the investigations show the that mechanical properties like tensile strength and material hardness can be adapted throughout the energy input per unit length significantly.

Polyvinylidene fluoride (PVDF) as a feedstock for material extrusion additive manufacturing

2020 ◽  
Vol 26 (1) ◽  
pp. 156-163 ◽  
Author(s):  
Niknam Momenzadeh ◽  
Hadi Miyanaji ◽  
Daniel Allen Porter ◽  
Thomas Austin Berfield
Keyword(s):  
Additive Manufacturing ◽  
Polyvinylidene Fluoride ◽  
Mechanical Response ◽  
Dimensional Accuracy ◽  
Piezoelectric Response ◽  
Content Type ◽  
Material Extrusion ◽  
Deposition Parameters ◽  
The Individual ◽  
Deposition Conditions

Purpose This study aims to investigate the material extrusion additive manufacturing (MEAM) deposition parameters for creating viable 3-D printed polyvinylidene fluoride (PVDF) structures with a balanced mix of mechanical and electrical properties. Design/methodology/approach Different combinations of deposition conditions are tested, and the influence of these parameters on the final dimensional accuracy, semi-crystalline phase microstructure and effective mechanical strength of MEAM homopolymer PVDF printed parts is experimentally assessed. Considering printed part integrity, appearance, print time and dimensional accuracy, MEAM parameters for PVDF are suggested. Findings A range of viable printing parameters for MEAM fabricated PVDF Kynar 740 objects of different heights and in-plane length dimensions was determined. For PVDF structures printed under the suggested conditions, the mechanical response and the microstructure development related to Piezoelectric response are reported. Originality/value This research first reports on a range of parameters that have been confirmed to facilitate effective MEAM printing of 3-D PVDF objects, presents effects of the individual parameters and gives the mechanical and microstructure properties of PVDF structures fabricated under the suggested deposition conditions.

Mechanical Properties of 5083 Aluminium Welds after Manual and Automatic Pulsed Gas Metal Arc Welding Using E5356 Filler

2010 ◽  
Vol 654-656 ◽  
pp. 2560-2563 ◽  
Author(s):  
Kalenda Mutombo ◽  
Madeleine du Toit
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Stress Concentration ◽  
Arc Welding ◽  
Gas Metal Arc Welding ◽  
Fatigue Properties ◽  
Filler Wire ◽  
Metal Arc Welding ◽  
Weld Toe ◽  
Fully Automatic

Semi-automatic and automatic pulsed gas metal arc welding (GMAW) of aluminium alloy 5083 with ER5356 filler wire causes considerable softening in the weld. The tensile strength of dressed automatic welds approaches that of the base metal, but the stress concentration caused by the weld toe in undressed semi-automatic welds reduced the tensile strength significantly. Fully automatic welds displayed improved fatigue properties compared to semi-automatic welds.

scholarly journals Development of a Multidirectional Wire Arc Additive Manufacturing (WAAM) Process with Pure Object Manipulation: Process Introduction and First Prototypes

2021 ◽  
Vol 5 (4) ◽  
pp. 134
Author(s):  
Khushal Parmar ◽  
Lukas Oster ◽  
Samuel Mann ◽  
Rahul Sharma ◽  
Uwe Reisgen ◽  
...  
Keyword(s):  
Additive Manufacturing ◽  
Gas Metal Arc Welding ◽  
Operating Conditions ◽  
Metal Arc Welding ◽  
Welding Torch ◽  
Building Process ◽  
Single Bead ◽  
Software Interfaces ◽  
Substrate Plate ◽  
Wire Arc Additive Manufacturing

Wire Arc Additive Manufacturing (WAAM) with eccentric wire feed requires defined operating conditions due to the possibility of varying shapes of the deposited and solidified material depending on the welding torch orientation. In consequence, the produced component can contain significant errors because single bead geometrical errors are cumulatively added to the next layer during a building process. In order to minimise such inaccuracies caused by torch manipulation, this article illustrates the concept and testing of object-manipulated WAAM by incorporating robotic and welding technologies. As the first step towards this target, robotic hardware and software interfaces were developed to control the robot. Alongside, a fixture for holding the substrate plate was designed and fabricated. After establishing the robotic setup, in order to complete the whole WAAM process setup, a Gas Metal Arc Welding (GMAW) process was built and integrated into the system. Later, an experimental plan was prepared to perform single and multilayer welding experiments as well as for different trajectories. According to this plan, several welding experiments were performed to decide the parametric working range for the further WAAM experiments. In the end, the results of the first multilayer depositions over intricate trajectories are shown. Further performance and quality optimization strategies are also discussed at the end of this article.

scholarly journals Pulse spray gas metal arc welding of advanced high strength S650MC automotive steel

10.30544/682 ◽  
2021 ◽  
Vol 27 (4) ◽  
pp. 505-517
Author(s):  
Ashok Kumar Srivastava ◽  
Pradip K Patra
Keyword(s):  
Weld Joint ◽  
Heat Input ◽  
Arc Welding ◽  
Gas Metal Arc Welding ◽  
High Strength Steels ◽  
High Strength ◽  
Filler Wire ◽  
Advanced High Strength Steels ◽  
Metal Arc Welding ◽  
The Impact

With an increasing demand for safer and greener vehicles, mild steel and high strength steel are being replaced by much stronger advanced high strength steels of thinner gauges. However, the welding process of advanced high strength steels is not developed at the same pace. The performance of these welded automotive structural components depends largely on the external and internal quality of weldment. Gas metal arc welding (GMAW) is one of the most common methods used in the automotive industry to join car body parts of dissimilar high strength steels. It is also recognized for its versatility and speed. In this work, after a review of GMAW process and issues in welding of advanced high strength steels, a welding experiment is carried out with varying heat input by using spray and pulse-spray transfer GMAW method with filler wires of three different strength levels. The experiment results, including macro-microstructure, mechanical properties, and microhardness of weld samples, are investigated in detail. Very good weldability of S650MC is demonstrated through the weld joint efficiency > 90%; no crack in bending of weld joints, or fracture of tensile test sample within weld joint or heat affected zone (HAZ), or softening of the HAZ. Pulse spray is superior because of thinner HAZ width and finer microstructure on account of lower heat input. The impact of filler wire strength on weldability is insignificant. However, high strength filler wire (ER100SG) may be chosen as per standard welding practice of matching strength.

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