Advanced Joining Processes and Techniques

A special issue of Journal of Manufacturing and Materials Processing (ISSN 2504-4494).

Deadline for manuscript submissions: closed (30 October 2021) | Viewed by 30523

Special Issue Editors

Department of Mechanical Engineering, Faculty of Engineering of the University of Porto, Rua Dr. Roberto Frias, s/n, 4200-465 Porto, Portugal
Interests: joining processes; materials design; engineering education
Special Issues, Collections and Topics in MDPI journals
John Deere (retired), Prof. St Ambrose University, Davenport, IA 52803, USA
Interests: fatigue of materials; joining; simulations; design; teaching
Department of Mechanical Engineering, University of Lisbon, 1649-004 Lisboa, Portugal
Interests: metal forming; metal cutting; manufacturing; finite element analysis; experimentation
Special Issues, Collections and Topics in MDPI journals
Institut für Schweißtechnik und Fügetechnik, RWTH Aachen University, Pontstraße 49, 52062 Aachen, Germany
Interests: welding; brazing; adhesive bonding
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear colleagues,

This Special Issue of the Journal of Manufacturing and Materials Processing includes selected papers presented at the 2nd International Conference on Advanced Joining Processes 2021 (AJP2021), to be held in Sintra (Portugal), on 21–22 October, 2021 (https://web.fe.up.pt/~ajp2021/).

The conference will provide a unique opportunity to exchange information, present the latest results, as well as discuss issues relevant to advanced methods of joining, such as friction stir welding, joining by plastic deformation, laser welding, advanced mechanical joining, adhesive bonding, and hybrid joining.

The focus is on process optimization in experimental and simulation terms, metallurgical and material behavior associated with joining, engineering properties and assessment of joints, health and safety aspects of joining, durability of joints in service, industrial applications, and education.

Other submissions (outside AJP2021) on advanced methods of joining processes are also welcome to be submitted to the Special Issue.

Prof. Dr. Lucas da Silva
Dr. Mohamad El-Zein
Prof. Dr. Paulo A. F. Martins
Prof. Dr. Uwe Reisgen
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Journal of Manufacturing and Materials Processing is an international peer-reviewed open access semimonthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 1800 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Published Papers (10 papers)

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Research

13 pages, 2586 KiB  
Article
Separation of Multi-Material Polymer Combinations Produced by Joining Using Pin-like Structures
by Michael Wolf and Dietmar Drummer
J. Manuf. Mater. Process. 2022, 6(1), 13; https://0-doi-org.brum.beds.ac.uk/10.3390/jmmp6010013 - 19 Jan 2022
Cited by 3 | Viewed by 2142
Abstract
In industrial applications, multi-material joints are becoming increasingly important to achieve a sustainable and resource-saving production. Not only high mechanical properties during the component use have to be given, but also possibilities to separate the joint after end of life are crucial. The [...] Read more.
In industrial applications, multi-material joints are becoming increasingly important to achieve a sustainable and resource-saving production. Not only high mechanical properties during the component use have to be given, but also possibilities to separate the joint after end of life are crucial. The recycling and re-use of the materials plays an increasing role in the process chain. Conventional multi-material joints can be separated by cutting out the joining zone, solvents, or thermal degradation. However, these methods result in a loss of material, damage to the base material, or high energy consumption. Therefore, novel joining methods are desirable, such as the joining using pin-like structures. The potential of this novel method for joining adhesion incompatible materials has been demonstrated in previous studies. This paper studies the separability of these connections. Therefore, joints between polyamide 66 (PA66) and polypropylene (PP) as well as PA66 and polymethylmethacrylate (PMMA) are investigated by means of thermal separation and shredding with subsequent sorting using the density difference of the materials. The separated components were investigated by analytical methods (including dissolution tests, viscosity number analysis, and Fourier-transform infrared spectroscopy) with respect to varietal purity and possible degradation effects. It could be shown that shredding allows a complete separation of the multi-material joint into its individual components without material residues or material loss. For thermal separation, material residues of PP or PMMA could be detected in the pin gaps of the PA66. For both separation methods, an influence on the base materials due to degradation effects could be excluded. It can be stated that joining using pin-like structures in vibration welding technology offers a sustainable production of multi-material joints with high recyclability. Full article
(This article belongs to the Special Issue Advanced Joining Processes and Techniques)
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17 pages, 5211 KiB  
Article
Development and Evaluation of the Ultrasonic Welding Process for Copper-Aluminium Dissimilar Welding
by Rafael Gomes Nunes Silva, Sylvia De Meester, Koen Faes and Wim De Waele
J. Manuf. Mater. Process. 2022, 6(1), 6; https://0-doi-org.brum.beds.ac.uk/10.3390/jmmp6010006 - 01 Jan 2022
Cited by 8 | Viewed by 3105
Abstract
The demand for joining dissimilar metals has exponentially increased due to the global concerns about climate change, especially for electric vehicles in the automotive industry. Ultrasonic welding (USW) surges as a very promising technique to join dissimilar metals, providing strength and electric conductivity, [...] Read more.
The demand for joining dissimilar metals has exponentially increased due to the global concerns about climate change, especially for electric vehicles in the automotive industry. Ultrasonic welding (USW) surges as a very promising technique to join dissimilar metals, providing strength and electric conductivity, in addition to avoid metallurgical defects, such as the formation of intermetallic compounds, brittle phases and porosities. However, USW is a very sensitive process, which depends on many parameters. This work evaluates the impact of the process parameters on the quality of ultrasonic spot welds between copper and aluminium plates. The weld quality is assessed based on the tensile strength of the joints and metallographic examination of the weld cross-sections. Furthermore, the welding energy is examined for the different welding conditions. This is done to evaluate the influence of each parameter on the heat input resulting from friction at the weld interface and on the weld quality. From the obtained results, it was possible to optimise parameters to achieve satisfactory weld quality in 1.0 mm thick Al–Cu plate joints in terms of mechanical and metallurgical properties. Full article
(This article belongs to the Special Issue Advanced Joining Processes and Techniques)
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13 pages, 6388 KiB  
Article
Influence of Surface Preparation on Cracking Phenomena in TIG-Welded High and Medium Entropy Alloys
by Tim Richter, Marcel Giese, Michael Rhode, Dirk Schroepfer, Thomas Michael and Tobias Fritsch
J. Manuf. Mater. Process. 2022, 6(1), 5; https://0-doi-org.brum.beds.ac.uk/10.3390/jmmp6010005 - 27 Dec 2021
Cited by 6 | Viewed by 2704
Abstract
Multi-element systems with defined entropy (HEA—high entropy alloy or MEA—medium entropy alloy) are rather new material concepts that are becoming increasingly important in materials research and development. Some HEA systems show significantly improved properties or combinations of properties, e.g., the overcoming of the [...] Read more.
Multi-element systems with defined entropy (HEA—high entropy alloy or MEA—medium entropy alloy) are rather new material concepts that are becoming increasingly important in materials research and development. Some HEA systems show significantly improved properties or combinations of properties, e.g., the overcoming of the trade-off between high strength and ductility. Thus, the synthesis, the resulting microstructures, and properties of HEA have been primarily investigated so far. In addition, processing is crucial to achieve a transfer of potential HEA/MEA materials to real applications, e.g., highly stressed components. Since fusion welding is the most important joining process for metals, it is of vital importance to investigate the weldability of these materials. However, this has rarely been the subject of research to date. For that reason, in this work, the weldability depending on the surface preparation of a CoCrFeMnNi HEA and a CoCrNi MEA for TIG welding is investigated. The fusion welding of longer plates is described here for the first time for the CoCrNi alloy. The welds of both materials showed distinct formation of cracks in the heat affected zone (HAZ). Optical and scanning electron microscopy analysis clearly confirmed an intergranular fracture topography. However, based on the results, the crack mechanism cannot be conclusively identified as either a liquid metal embrittlement (LME) or hot cracking-like liquid film separation. Full article
(This article belongs to the Special Issue Advanced Joining Processes and Techniques)
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19 pages, 9314 KiB  
Article
Local Shielding Gas Supply in Remote Laser Beam Welding
by Klaus Schricker, Andreas Baumann and Jean Pierre Bergmann
J. Manuf. Mater. Process. 2021, 5(4), 139; https://0-doi-org.brum.beds.ac.uk/10.3390/jmmp5040139 - 17 Dec 2021
Cited by 1 | Viewed by 2288
Abstract
The use of shielding gases in laser beam welding is of particular interest for materials interacting with ambient oxygen, e.g., copper, titanium or high-alloy steels. These materials are often processed by remote laser beam welding where short welds (e.g., up to 40 mm [...] Read more.
The use of shielding gases in laser beam welding is of particular interest for materials interacting with ambient oxygen, e.g., copper, titanium or high-alloy steels. These materials are often processed by remote laser beam welding where short welds (e.g., up to 40 mm seam length) are commonly used. Such setups prevent gas nozzles from being carried along on the optics due to the scanner application and a small area needs to be served locally with inert gas. The article provides systematic investigations into the interaction of laser beam processes and parameters of inert gas supply based on a modular flat jet nozzle. Based on the characterization of the developed nozzle by means of high-speed Schlieren imaging and constant temperature anemometry, investigations with heat conduction welding and deep penetration welding were performed. Bead-on-plate welds were carried out on stainless steel AISI 304 for this purpose using a disc laser and a remote welding system. Argon was used as shielding gas. The interaction between Reynolds number, geometrical parameters and welding/flow direction was considered. The findings were proved by transferring the results to a complex weld seam geometry (C-shape). Full article
(This article belongs to the Special Issue Advanced Joining Processes and Techniques)
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14 pages, 3502 KiB  
Article
Laser Welding of AISI 316L Stainless Steel Produced by Additive Manufacturing or by Conventional Processes
by Morgane Mokhtari, Pierrick Pommier, Yannick Balcaen and Joel Alexis
J. Manuf. Mater. Process. 2021, 5(4), 136; https://0-doi-org.brum.beds.ac.uk/10.3390/jmmp5040136 - 14 Dec 2021
Cited by 13 | Viewed by 3547
Abstract
Among all the additive manufacturing techniques, Laser Powder Bed Fusion (LBPF), also called Selective Laser Melting (SLM), is the most common technique due to its high capability of building complex parts with generally improved mechanical properties. One of the main drawbacks of this [...] Read more.
Among all the additive manufacturing techniques, Laser Powder Bed Fusion (LBPF), also called Selective Laser Melting (SLM), is the most common technique due to its high capability of building complex parts with generally improved mechanical properties. One of the main drawbacks of this technique is the sample size limitation, which depends on elaborating chamber dimensions. In this study, we investigate the viability of obtaining large parts with the laser welding of additive manufactured plates. A comparison of the microstructure and the tensile mechanical properties of SLM-welded plates and cold-rolled welded plates was performed. This paper shows the possibility of obtaining defect-free parts. Even if welding has a low impact on the microstructure of the SLM samples, fractures are located on the fusion zone, and a decrease in ductility of around 30% compared to the base metal is observed. Full article
(This article belongs to the Special Issue Advanced Joining Processes and Techniques)
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14 pages, 4816 KiB  
Article
Detecting Process Anomalies in the GMAW Process by Acoustic Sensing with a Convolutional Neural Network (CNN) for Classification
by Maximilian Rohe, Benedict Niklas Stoll, Jörg Hildebrand, Jan Reimann and Jean Pierre Bergmann
J. Manuf. Mater. Process. 2021, 5(4), 135; https://0-doi-org.brum.beds.ac.uk/10.3390/jmmp5040135 - 11 Dec 2021
Cited by 9 | Viewed by 2901
Abstract
Today, the quality of welded seams is often examined off-line with either destructive or non-destructive testing. These test procedures are time-consuming and therefore costly. This is especially true if the welds are not welded accurately due to process anomalies. In manual welding, experienced [...] Read more.
Today, the quality of welded seams is often examined off-line with either destructive or non-destructive testing. These test procedures are time-consuming and therefore costly. This is especially true if the welds are not welded accurately due to process anomalies. In manual welding, experienced welders are able to detect process anomalies by listening to the sound of the welding process. In this paper, an approach to transfer the “hearing” of an experienced welder into an automated testing process is presented. An acoustic measuring device for recording audible sound is installed for this purpose on a fully automated welding fixture. The processing of the sound information by means of machine learning methods enables in-line process control. Existing research results until now show that the arc is the main sound source. However, both the outflow of the shielding gas and the wire feed emit sound information. Other investigations describe welding irregularities by evaluating and assessing existing sound recordings. Descriptive analysis was performed to find a connection between certain sound patterns and welding irregularities. Recent contributions have used machine learning to identify the degree of welding penetration. The basic assumption of the presented investigations is that process anomalies are the cause of welding irregularities. The focus was on detecting deviating shielding gas flow rates based on audio recordings, processed by a convolutional neural network (CNN). After adjusting the hyperparameters of the CNN it was capable of distinguishing between different flow rates of shielding gas. Full article
(This article belongs to the Special Issue Advanced Joining Processes and Techniques)
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14 pages, 8848 KiB  
Article
Development of a Multidirectional Wire Arc Additive Manufacturing (WAAM) Process with Pure Object Manipulation: Process Introduction and First Prototypes
by Khushal Parmar, Lukas Oster, Samuel Mann, Rahul Sharma, Uwe Reisgen, Markus Schmitz, Thomas Nowicki, Jan Wiartalla, Mathias Hüsing and Burkhard Corves
J. Manuf. Mater. Process. 2021, 5(4), 134; https://0-doi-org.brum.beds.ac.uk/10.3390/jmmp5040134 - 10 Dec 2021
Cited by 5 | Viewed by 3484
Abstract
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 [...] Read more.
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. Full article
(This article belongs to the Special Issue Advanced Joining Processes and Techniques)
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13 pages, 4513 KiB  
Article
High-Precision Adjustment of Welding Depth during Laser Micro Welding of Copper Using Superpositioned Spatial and Temporal Power Modulation
by Marc Hummel, André Häusler and Arnold Gillner
J. Manuf. Mater. Process. 2021, 5(4), 127; https://0-doi-org.brum.beds.ac.uk/10.3390/jmmp5040127 - 25 Nov 2021
Cited by 5 | Viewed by 2931
Abstract
For joining metallic materials for battery applications such as copper and stainless steel, laser beam micro welding with beam sources in the near-infrared range has become established in recent years. In laser beam micro welding, spatial power modulation describes the superposition of the [...] Read more.
For joining metallic materials for battery applications such as copper and stainless steel, laser beam micro welding with beam sources in the near-infrared range has become established in recent years. In laser beam micro welding, spatial power modulation describes the superposition of the linear feed motion with an oscillating motion. This modulation method serves to widen the cross-section of the weld seam as well as to increase the process stability. Temporal power modulation refers to the controlled modulation of the laser power over time during the welding process. In this paper, the superposition of both temporal and spatial power modulation methods is presented, which enables a variable control of the weld penetration depth. Three weld geometries transverse to the feed direction are part of this investigation: the compensation of the weld penetration depth due to the asymmetric path movement during spatial power modulation only, a W-shaped weld profile, and a V-shaped. The weld geometries are investigated by the bed on plate weld tests with CuSn6. Furthermore, the use of combined power modulation for welding tests in butt joint configuration between CuSn6 and stainless steel 1.4301 with different material properties is investigated. The study shows the possibility of precise control of the welding depth by this methodology. Depending on the material combination, the desired regions with maximum and minimum welding depth can be achieved by the control of local and temporal power modulation on the material surface. Full article
(This article belongs to the Special Issue Advanced Joining Processes and Techniques)
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13 pages, 4201 KiB  
Communication
Evaluating Temperature Control in Friction Stir Welding for Industrial Applications
by Arnold Wright, Troy R. Munro and Yuri Hovanski
J. Manuf. Mater. Process. 2021, 5(4), 124; https://0-doi-org.brum.beds.ac.uk/10.3390/jmmp5040124 - 19 Nov 2021
Cited by 8 | Viewed by 2813
Abstract
Reports in the literature indicate that temperature control in Friction Stir Welding (FSW) enables better weld properties and easier weld process development. However, although methods of temperature control have existed for almost two decades, industry adoption remains limited. This work examines single-loop Proportional-Integral-Derivative [...] Read more.
Reports in the literature indicate that temperature control in Friction Stir Welding (FSW) enables better weld properties and easier weld process development. However, although methods of temperature control have existed for almost two decades, industry adoption remains limited. This work examines single-loop Proportional-Integral-Derivative (PID) control on spindle speed as a comparatively simple and cost-effective method of adding temperature control to existing FSW machines. Implementation of PID-based temperature control compared to uncontrolled FSW in AA6111 at linear weld speeds of 1–2 m per minute showed improved mechanical properties and greater consistency in properties along the length of the weld under temperature control. Additionally, results indicate that a minimum spindle rpm may exist, above which tensile specimens do not fracture within the weld centerline, regardless of temperature. This work demonstrates that a straightforward, PID-based implementation of temperature control at high weld rates can produce high quality welds. Full article
(This article belongs to the Special Issue Advanced Joining Processes and Techniques)
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20 pages, 8098 KiB  
Article
Evaluation of Optimization Parameters of Semi-Solid Metal 6063 Aluminum Alloy from Friction Stir Welding Process Using Factorial Design Analysis
by Chaiyoot Meengam and Kittima Sillapasa
J. Manuf. Mater. Process. 2020, 4(4), 123; https://0-doi-org.brum.beds.ac.uk/10.3390/jmmp4040123 - 17 Dec 2020
Cited by 11 | Viewed by 3186
Abstract
The semi-solid-metal 6063 aluminum alloy was developed for the automotive industry. The objective of this research was to optimize parameters in friction stir welding process that can provide the highest tensile strength. The ANOVA factorial design was used to analyze rotation speed, welding [...] Read more.
The semi-solid-metal 6063 aluminum alloy was developed for the automotive industry. The objective of this research was to optimize parameters in friction stir welding process that can provide the highest tensile strength. The ANOVA factorial design was used to analyze rotation speed, welding speed, and tool geometry at different factor levels of experimentation. The results showed that the optimized tensile strength was 120.7 MPa from the cylindrical tool, rotation speed was from 1300 to 2100 rpm, and welding speed less than 75 mm/min in the coefficient of determination R2 was 95.09%, as can be considered from the regression equation. The examination of the stir-zone and thermal mechanical affected zone using SEM and EDX showed that the new recrystallization of the microstructure causes fine grain in the stir-zone, coarse grain in advancing-side thermal mechanical affected zone, and equiaxed grain in the retracting-side thermal-mechanical affect zone. The intermetallic compounds of β-Al5FeSi phase transformation phase were formed to three types, i.e., β″-Al5Fe, Mg2Si, and Al8Fe2Si phase were observed. Moreover, in the stir-zone and thermal-mechanical-affected zone, defects were found such as flash defects, void or cavity defects, crack defects, lack of penetration defects, tunnel defects, kissing bond defects, and dendrite formation defects affecting weldability. Full article
(This article belongs to the Special Issue Advanced Joining Processes and Techniques)
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