Journal of Manufacturing and Materials Processing

20 pages, 11242 KiB

Open AccessArticle

Reprocessability of PLA through Chain Extension for Fused Filament Fabrication

by Carlos Correia, Tiago E. P. Gomes, Idalina Gonçalves and Victor Neto

J. Manuf. Mater. Process. 2022, 6(1), 26; https://doi.org/10.3390/jmmp6010026 - 19 Feb 2022

Cited by 11 | Viewed by 3532

As additive manufacturing (AM) technologies have been gaining popularity in the plastic processing sector, it has become a major concern to establish closed-loop recycling strategies to maximize the value of the materials processed, therefore enhancing their sustainability. However, there are challenges to overcome [...] Read more.

As additive manufacturing (AM) technologies have been gaining popularity in the plastic processing sector, it has become a major concern to establish closed-loop recycling strategies to maximize the value of the materials processed, therefore enhancing their sustainability. However, there are challenges to overcome related to the performance of recycled materials since, after mechanical recycling, the molecular degradation of thermoplastics shifts their performance and processability. In this work, it was hypothesized that the incorporation of a chain extender (CE) during the reprocessing would allow us to overcome these drawbacks. To attest this conjecture, the influence of 1,3-Bis(4,5-dihydro-2-oxazolyl)benzene (PBO), used as a CE, on mechanical, thermal, and rheological properties of polilactic acid (PLA) was studied. Furthermore, a closed-loop recycling system based on Fused Filament Fabrication (FFF) was attempted, consisting of the material preparation, filament extrusion, production of 3D components, and mechanical recycling steps. PBO partially recovered the recycled PLA mechanical performance, reflected by an increase in both tensile modulus (+13%) and tensile strength (+121%), when compared with recycled PLA without PBO. Printability tests were conducted, with the material’s brittle behavior being the major constraint for successfully establishing a closed-loop recycling scheme for FFF applications. Full article

(This article belongs to the Special Issue Manufacturing and Processing of Recycled Plastics)

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10 pages, 5010 KiB

Open AccessCommunication

Build Surface Roughness and Internal Oxide Concentration for Laser Powder Bed Fusion of IN718

by Lonnie A. Smith and Petrus Christiaan Pistorius

J. Manuf. Mater. Process. 2022, 6(1), 25; https://doi.org/10.3390/jmmp6010025 - 16 Feb 2022

Viewed by 2051

Abstract

Oxidation of hot spatter during laser powder bed fusion results in the deposition of oxides on the build surface. In the case of IN718—as studied in this work—the oxide is alumina. While some of this surface oxide may be incorporated in the build, [...] Read more.

Oxidation of hot spatter during laser powder bed fusion results in the deposition of oxides on the build surface. In the case of IN718—as studied in this work—the oxide is alumina. While some of this surface oxide may be incorporated in the build, an oxygen mass balance indicates some oxygen removal during the building process. This work tested an expected effect of the roughness of the build surface on the concentration of micron-sized oxide inclusions that are incorporated in test coupons during building. The roughness of the build surface responded to changes in hatch spacing, in line with a simple geometric model of the overlap between adjacent beads. Samples with deeper grooves retained more oxide, resulting in a much larger concentration of oxide inclusions within the samples. The conclusion is that parts with lower inclusion concentrations can be produced by decreasing the hatch spacing, at the cost of a lower build rate. Full article

(This article belongs to the Special Issue Frontiers in Digital Manufacturing)

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22 pages, 17301 KiB

Open AccessEditor’s ChoiceArticle

Effect of Rotation Speed and Steel Microstructure on Joint Formation in Friction Stir Spot Welding of Al Alloy to DP Steel

by Hadi Torkamani, Javier Vivas Méndez, Clement Lecart, Egoitz Aldanondo Begiristain, Pedro Alvarez Moro and Marta-Lena Antti

J. Manuf. Mater. Process. 2022, 6(1), 24; https://doi.org/10.3390/jmmp6010024 - 15 Feb 2022

Cited by 3 | Viewed by 2793

Abstract

In this work, friction stir spot welding of 5754 aluminum alloy to dual phase steel was investigated using two different ratios of martensite and ferrite (0.38 and 0.61) for steel sheet initial microstructure and varying tool rotation speed (800, 1200 and 2000 rpm). [...] Read more.

In this work, friction stir spot welding of 5754 aluminum alloy to dual phase steel was investigated using two different ratios of martensite and ferrite (0.38 and 0.61) for steel sheet initial microstructure and varying tool rotation speed (800, 1200 and 2000 rpm). The effect of these parameters on the joint formation was evaluated by studying the plunging force response during the process and the main characteristics of the joint at (i) macrolevel, i.e., hook morphology and bond width, and (ii) microlevel, i.e., steel hook and sheet microstructure and intermetallic compounds. The plunging force was reduced by increased tool rotation speed while there was no significant effect from the initial steel microstructure ratio of martensite and ferrite on the plunging force. The macrostructural characterization of the joints showed that the hook morphology and bond width were affected by the steel sheet initial microstructures as well as by the tool rotation speed and by the material flow driver; tool pin or shoulder. At microstructural level, a progressive variation in the ratio of martensite and ferrite was observed for the steel hook and sheet microstructure. The zones closer to the tool presented a fully martensitic microstructure while the zones away from the tool showed a gradual increase in the ferrite amount until reaching the ratio of ferrite and martensite of the steel sheet initial microstructure. Different types of FexAly intermetallic compounds were found in three zones of the joint; the hook tips, in the hooks close to the exit hole and in the corner of the exit hole. These compounds were characterized by a brittle behavior with hardness values varying from 456 to 937 HV01. Full article

(This article belongs to the Special Issue Frontiers in Friction Stir Welding and Processing)

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26 pages, 20200 KiB

Open AccessArticle

Stability Evaluation for a Damped, Constrained-Motion Cutting Force Dynamometer

by Michael Gomez and Tony Schmitz

J. Manuf. Mater. Process. 2022, 6(1), 23; https://doi.org/10.3390/jmmp6010023 - 10 Feb 2022

Cited by 2 | Viewed by 2604

Abstract

This paper describes the dynamic stability evaluation of a constrained-motion dynamometer (CMD) with passive damping. The CMD’s flexure-based design offers an alternative to traditional piezoelectric cutting force dynamometers, which can exhibit adverse effects of the complex structural dynamics on the measurement accuracy. In [...] Read more.

This paper describes the dynamic stability evaluation of a constrained-motion dynamometer (CMD) with passive damping. The CMD’s flexure-based design offers an alternative to traditional piezoelectric cutting force dynamometers, which can exhibit adverse effects of the complex structural dynamics on the measurement accuracy. In contrast, the CMD system’s structural dynamics are nominally single degree of freedom and are conveniently altered by material selection, flexure element geometry, and element arrangement. In this research, a passive damping approach is applied to increase the viscous damping ratio and, subsequently, the stability limit. Cutting tests were completed and the in situ CMD displacement and velocity signals were sampled at the spindle rotating frequency. The periodic sampling approach was used to determine if the milling response was synchronous with the spindle rotation (stable) or not (chatter) by constructing Poincaré maps for both experiment and prediction (time-domain simulation). It was found that the viscous damping coefficient was increased by 130% and the critical stability limit was increased from 4.3 mm (no damping) to 15.4 mm (with damping). Full article

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24 pages, 7205 KiB

Open AccessArticle

Systematic Development of a Powder Deposition System for an Open Selective Laser Sintering Machine Using Analytic Hierarchy Process

by Foivos Psarommatis and George-Christopher Vosniakos

J. Manuf. Mater. Process. 2022, 6(1), 22; https://doi.org/10.3390/jmmp6010022 - 8 Feb 2022

Cited by 7 | Viewed by 2873

Abstract

This work reports on the design and manufacture of an efficient system for powder deposition into layers in an open Selective Laser Sintering machine. The system comprises mainly two subsystems, i.e., one that deposits a dose of powder onto the worktable and another [...] Read more.

This work reports on the design and manufacture of an efficient system for powder deposition into layers in an open Selective Laser Sintering machine. The system comprises mainly two subsystems, i.e., one that deposits a dose of powder onto the worktable and another that levels the powder upon its deposition. The design was conducted in two phases, namely conceptualization of the system and its detailed design. The conceptualization phase exploited the Analytic Hierarchy Process to evaluate alternative mechanical systems and determine the most suitable one. This was subsequently detail-designed using a CAD software package and then followed by selection of the necessary electronics for imparting and controlling motion of the individual mechanisms comprising the system. As regards manufacturing, custom designed components were obtained by CNC machining and the entire mechanism was assembled on an open Selective Laser Sintering machine. Functionality testing of the system was performed with satisfactory results. Full article

(This article belongs to the Special Issue Direct Digital Manufacturing with Additive Manufacturing/3D Printing)

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21 pages, 7108 KiB

Open AccessEditor’s ChoiceArticle

Microstructure and Mechanical Properties of Ti-6Al-4V Additively Manufactured by Electron Beam Melting with 3D Part Nesting and Powder Reuse Influences

by Priti Wanjara, David Backman, Fatih Sikan, Javad Gholipour, Robert Amos, Prakash Patnaik and Mathieu Brochu

J. Manuf. Mater. Process. 2022, 6(1), 21; https://doi.org/10.3390/jmmp6010021 - 1 Feb 2022

Cited by 20 | Viewed by 5203

Abstract

To better support the transition to more industrial uses of additive manufacturing, this study examined the use of an Arcam Q20+ industrial 3D printer for producing heavily nested Ti-6Al-4V parts with both in-specification (IS) and out of specification (OS) oxygen content in reused [...] Read more.

To better support the transition to more industrial uses of additive manufacturing, this study examined the use of an Arcam Q20+ industrial 3D printer for producing heavily nested Ti-6Al-4V parts with both in-specification (IS) and out of specification (OS) oxygen content in reused grade 5 powder chemistries. Both the OS and IS powder chemistries were evaluated to understand their impact on build integrity and on static and fatigue performance. The results from our evaluations showed that controlling the bed preheat temperature in the Q20+ to relatively low values (326–556 °C) was effective in limiting microstructural coarsening during the long build time and enabled adequate/balanced performance vis à vis the tensile strength and ductility. Overall, the tensile properties of the IS Ti-6Al-4V material in the as-built and machined states fully met the requirements of ASTM F2924-14. By contrast, the ductility was compromised at oxygen levels above 0.2 wt.% (OS) in Ti-6Al-4V produced by EBM. Removal of the surface layer by machining increased the consistency and performance of the IS and OS Ti-6Al-4V materials. The fatigue behaviour of the EBM Ti-6Al-4V material was in the range of properties produced by casting. Due to the strong influence of both the surface finish and oxygen content on the fatigue strength, the IS Ti-6Al-4V material exhibited the highest performance, with results that were in the range of parts that had been cast plus hot isostatically pressed. Full article

(This article belongs to the Special Issue Advances in Metal Additive Manufacturing/3D Printing)

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20 pages, 5499 KiB

Open AccessEditor’s ChoiceArticle

Microstructure Evolution in Inconel 718 Produced by Powder Bed Fusion Additive Manufacturing

by Judy Schneider, Laura Farris, Gert Nolze, Stefan Reinsch, Grzegorz Cios, Tomasz Tokarski and Sean Thompson

J. Manuf. Mater. Process. 2022, 6(1), 20; https://doi.org/10.3390/jmmp6010020 - 29 Jan 2022

Cited by 7 | Viewed by 5230

Abstract

Inconel 718 is a precipitation strengthened, nickel-based super alloy of interest for the Additive Manufacturing (AM) of low volume, complex parts to reduce production time and cost compared to conventional subtractive processes. The AM process involves repeated rapid melting, solidification and reheating, which [...] Read more.

Inconel 718 is a precipitation strengthened, nickel-based super alloy of interest for the Additive Manufacturing (AM) of low volume, complex parts to reduce production time and cost compared to conventional subtractive processes. The AM process involves repeated rapid melting, solidification and reheating, which exposes the material to non-equilibrium conditions that affect elemental segregation and the subsequent formation of solidification phases, either beneficial or detrimental. These variations are difficult to characterize due to the small length scale within the micron sized melt pool. To understand how the non-equilibrium conditions affect the initial solidification phases and their critical temperatures, a multi-length scale, multi modal approach has been taken to evaluate various methods for identifying the initial phases formed in the as-built Inconel 718 produced by laser-powder bed fusion (L-PBF) additive manufacturing (AM). Using a range of characterization tools from the bulk differential thermal analysis (DTA) and x-ray diffraction (XRD) to spatially resolved images using a variety of electron microscopy tools, a better understanding is obtained of how these minor phases can be properly identified regarding the amount and size, morphology and distribution. Using the most promising characterization techniques for investigation of the as-built specimens, those techniques were used to evaluate the specimens after various heat treatments. During the sequence of heat treatments, the initial as-built dendritic structures recrystallized into well-defined grains whose size was dependent on the temperature. Although the resulting strength was similar in all heat treated specimens, the elongation increased as the grain size was refined due to differences in the precipitated phase distribution and morphology. Full article

(This article belongs to the Topic Additive Manufacturing)

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5 pages, 167 KiB

Open AccessEditorial

Acknowledgment to Reviewers of JMMP in 2021

by JMMP Editorial Office

J. Manuf. Mater. Process. 2022, 6(1), 19; https://doi.org/10.3390/jmmp6010019 - 26 Jan 2022

Viewed by 1714

Abstract

Rigorous peer-reviews are the basis of high-quality academic publishing [...] Full article

18 pages, 7500 KiB

Open AccessArticle

A Novel Approach for Real-Time Quality Monitoring in Machining of Aerospace Alloy through Acoustic Emission Signal Transformation for DNN

by David Adeniji, Kyle Oligee and Julius Schoop

J. Manuf. Mater. Process. 2022, 6(1), 18; https://doi.org/10.3390/jmmp6010018 - 25 Jan 2022

Cited by 11 | Viewed by 3241

Abstract

Gamma titanium aluminide (γ-TiAl) is considered a high-performance, low-density replacement for nickel-based superalloys in the aerospace industry due to its high specific strength, which is retained at temperatures above 800 °C. However, low damage tolerance, i.e., brittle material behavior with a propensity to [...] Read more.

Gamma titanium aluminide (γ-TiAl) is considered a high-performance, low-density replacement for nickel-based superalloys in the aerospace industry due to its high specific strength, which is retained at temperatures above 800 °C. However, low damage tolerance, i.e., brittle material behavior with a propensity to rapid crack propagation, has limited the application of γ-TiAl. Any cracks introduced during manufacturing would dramatically lower the useful (fatigue) life of γ-TiAl components, making the workpiece surface’s quality from finish machining a critical component to product quality and performance. To address this issue and enable more widespread use of γ-TiAl, this research aims to develop a real-time non-destructive evaluation (NDE) quality monitoring technique based on acoustic emission (AE) signals, wavelet transform, and deep neural networks (DNN). Previous efforts have opted for traditional approaches to AE signal analysis, using statistical feature extraction and classification, which face challenges such as the extraction of good/relevant features and low classification accuracy. Hence, this work proposes a novel AI-enabled method that uses a convolutional neural network (CNN) to extract rich and relevant features from a two-dimensional image representation of 1D time-domain AE signals (known as scalograms), subsequently classifying the AE signature based on pedigreed experimental data and finally predicting the process-induced surface quality. The results of the present work show good classification accuracy of 80.83% using scalogram images, in-situ experimental data, and a VGG-19 pre-trained neural network, establishing the significant potential for real-time quality monitoring in manufacturing processes. Full article

(This article belongs to the Topic Artificial Intelligence in Smart Industrial Diagnostics and Manufacturing)

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24 pages, 101637 KiB

Open AccessEditor’s ChoiceReview

Vat Photopolymerization Additive Manufacturing of Functionally Graded Materials: A Review

by Serkan Nohut and Martin Schwentenwein

J. Manuf. Mater. Process. 2022, 6(1), 17; https://doi.org/10.3390/jmmp6010017 - 21 Jan 2022

Cited by 33 | Viewed by 7341

Abstract

Functionally Graded Materials (FGMs) offer discrete or continuously changing properties/compositions over the volume of the parts. The widespread application of FGMs was not rapid enough in the past due to limitations of the manufacturing methods. Significant developments in manufacturing technologies especially in Additive [...] Read more.

Functionally Graded Materials (FGMs) offer discrete or continuously changing properties/compositions over the volume of the parts. The widespread application of FGMs was not rapid enough in the past due to limitations of the manufacturing methods. Significant developments in manufacturing technologies especially in Additive Manufacturing (AM) enable us nowadays to manufacture materials with specified changes over the volume/surface of components. The use of AM methods for the manufacturing of FGMs may allow us to compensate for some drawbacks of conventional methods and to produce complex and near-net-shaped structures with better control of gradients in a cost-efficient way. Vat Photopolymerization (VP), a type of AM method that works according to the principle of curing liquid photopolymer resin layer-by-layer, has gained in recent years high importance due to its advantages such as low cost, high surface quality control, no need to support structures, no limitation in the material. This article reviews the state-of-art and future potential of using VP methods for FGM manufacturing. It was concluded that improvements in printer hardware setup and software, design aspects and printing methodologies will accelerate the use of VP methods for FGMs manufacturing. Full article

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34 pages, 6919 KiB

Open AccessEditor’s ChoiceReview

A Review on the Processing of Aero-Turbine Blade Using 3D Print Techniques

by Ayush Sinha, Biswajit Swain, Asit Behera, Priyabrata Mallick, Saswat Kumar Samal, H. M. Vishwanatha and Ajit Behera

J. Manuf. Mater. Process. 2022, 6(1), 16; https://doi.org/10.3390/jmmp6010016 - 21 Jan 2022

Cited by 26 | Viewed by 17332

Abstract

Additive manufacturing (AM) has proven to be the preferred process over traditional processes in a wide range of industries. This review article focused on the progressive development of aero-turbine blades from conventional manufacturing processes to the additive manufacturing process. AM is known as [...] Read more.

Additive manufacturing (AM) has proven to be the preferred process over traditional processes in a wide range of industries. This review article focused on the progressive development of aero-turbine blades from conventional manufacturing processes to the additive manufacturing process. AM is known as a 3D printing process involving rapid prototyping and a layer-by-layer construction process that can develop a turbine blade with a wide variety of options to modify the turbine blade design and reduce the cost and weight compared to the conventional production mode. This article describes various AM techniques suitable for manufacturing high-temperature turbine blades such as selective laser melting, selective laser sintering, electron beam melting, laser engineering net shaping, and electron beam free form fabrication. The associated parameters of AM such as particle size and shape, powder bed density, residual stresses, porosity, and roughness are discussed here. Full article

(This article belongs to the Special Issue Advances in Material Forming)

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36 pages, 9316 KiB

Open AccessEditor’s ChoiceReview

Advanced Processing and Machining of Tungsten and Its Alloys

by Samuel Omole, Alexander Lunt, Simon Kirk and Alborz Shokrani

J. Manuf. Mater. Process. 2022, 6(1), 15; https://doi.org/10.3390/jmmp6010015 - 20 Jan 2022

Cited by 14 | Viewed by 7842

Abstract

Tungsten is a refractory metal with the highest melting temperature and density of all metals in this group. These properties, together with the high thermal conductivity and strength, make tungsten the ideal material for high-temperature structural use in fusion energy and other applications. [...] Read more.

Tungsten is a refractory metal with the highest melting temperature and density of all metals in this group. These properties, together with the high thermal conductivity and strength, make tungsten the ideal material for high-temperature structural use in fusion energy and other applications. It is widely agreed that the manufacture of components with complex geometries is crucial for scaling and optimizing power plant designs. However, there are challenges associated with the large-scale processing and manufacturing of parts made from tungsten and its alloys which limit the production of these complex geometries. These challenges stem from the high ductile-to-brittle transition temperature (DBTT), as well as the strength and hardness of these parts. Processing methods, such as powder metallurgy and additive manufacturing, can generate near-net-shaped components. However, subtractive post-processing techniques are required to complement these methods. This paper provides an in-depth exploration and discussion of different processing and manufacturing methods for tungsten and identifies the challenges and gaps associated with each approach. It includes conventional and unconventional machining processes, as well as research on improving the ductility of tungsten using various methods, such as alloying, thermomechanical treatment, and grain structure refinement. Full article

(This article belongs to the Special Issue Anniversary Review and Feature Papers)

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19 pages, 60402 KiB

Open AccessArticle

Study on Magnetic Abrasive Finishing Combined with Electrolytic Process–Precision Surface Finishing for SUS 304 Stainless Steel Using Pulse Voltage

by Baijun Xing, Yanhua Zou and Masahisa Tojo

J. Manuf. Mater. Process. 2022, 6(1), 14; https://doi.org/10.3390/jmmp6010014 - 19 Jan 2022

Cited by 4 | Viewed by 2422

Abstract

In order to further study the Magnetic Abrasive Finishing with Electrolytic (EMAF) Process, we attempted to use rectangular wave pulse voltage for EMAF processing of SUS304 stainless steel, and the finishing characteristics were analyzed based on the experimental results in this paper. The [...] Read more.

In order to further study the Magnetic Abrasive Finishing with Electrolytic (EMAF) Process, we attempted to use rectangular wave pulse voltage for EMAF processing of SUS304 stainless steel, and the finishing characteristics were analyzed based on the experimental results in this paper. The EMAF process has been studied for years, but the study of Magnetic Abrasive Finishing with the. Pulse Electrolytic (P-EMAF) process has not been published. Therefore, in this study, the finishing characteristics of the P-EMAF process corresponding to different frequencies (1 Hz, 10 Hz, 100 Hz, 1 kHz) and duty ratios (25%, 50%, 75%) are explored. The evaluation of the P-EMAF processing includes the surface roughness (SR) and the amount of material removal (MR); the surface of the workpiece was also observed by an optical microscope before and after processing. After analyzing the experimental results of P-EMAF processing, a set of comparative experiments between P-EMAF processing and MAF processing was carried out. In this study, when the U_rms 6 V pulse voltage of rectangular wave with 1 Hz and duty ratio 50% was used, a better processing result could be obtained. The processing efficiency of the P-EMAF process was also higher than that of the MAF process under the same experimental conditions. Full article

(This article belongs to the Special Issue Advanced Surface Finishing Processes)

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13 pages, 2586 KiB

Open AccessArticle

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://doi.org/10.3390/jmmp6010013 - 19 Jan 2022

Cited by 3 | Viewed by 2222

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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21 pages, 6101 KiB

Open AccessCommunication

Wind Tunnel Experiments on an Aircraft Model Fabricated Using a 3D Printing Technique

by Katarzyna Szwedziak, Tomasz Łusiak, Robert Bąbel, Przemysław Winiarski, Sebastian Podsędek, Petr Doležal and Gniewko Niedbała

J. Manuf. Mater. Process. 2022, 6(1), 12; https://doi.org/10.3390/jmmp6010012 - 18 Jan 2022

Cited by 8 | Viewed by 4427

Abstract

Experimental tests regarding the M-346 aircraft model made via 3D printing were carried out in order to obtain numerical data and characteristics in the form of graphs of basic aerodynamic forces and coefficients. The tests were carried out for the left side of [...] Read more.

Experimental tests regarding the M-346 aircraft model made via 3D printing were carried out in order to obtain numerical data and characteristics in the form of graphs of basic aerodynamic forces and coefficients. The tests were carried out for the left side of the airframe model in a clean configuration, without additional suspension equipment; the flight control surfaces and the aerodynamic brake were in neutral positions. Based on the scan of the base model in 1:48 scale using a Nikon Model Maker MMDx laser scanning head, followed by the generation and optimization of some of the airframe elements in SolidWorks software, a test model ready for printing was prepared. Using the MakerBot Print program, the printing parameters were set, and the process itself was completed using a MakerBot Replicator Z18 3D printer. The next step was manual treatment in order to remove the material excess from the melted thermoplastic material, join the elements and appropriately polish the surface of the tested model in order to obtain the desired quality. The test was carried out using a Gunt HM 170 wind tunnel for fixed airflow velocities at variable angles of attack. On this basis, the numerical values of lift force, Pz, and drag force, Px, were obtained; then, the lift force indices, Cz, and drag force indices, Cx, were computed for the steady states, which were for angle α from −12 to 16°. The use of 3D printing contributed to the generation of geometry, which, for research purposes, was scaled down in order to fully use the available measurement space of the wind tunnel. The final stage of the work was to compare the obtained curves of particular characteristics with the literature data. Full article

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19 pages, 5810 KiB

Open AccessArticle

Study of Tailored Hot Stamping Process on Advanced High-Strength Steels

by Maria Emanuela Palmieri, Francesco Rocco Galetta and Luigi Tricarico

J. Manuf. Mater. Process. 2022, 6(1), 11; https://doi.org/10.3390/jmmp6010011 - 18 Jan 2022

Cited by 20 | Viewed by 3720

Abstract

Ultra-high-strength steels (UHSS) combined with tailor-stamping technologies are increasingly being adopted in automotive body production due to crashworthiness improvements and part weight reduction, which meet safety and energy saving demands. Recently, USIBOR^®2000 (37MnB5) steel has been added to the family of [...] Read more.

Ultra-high-strength steels (UHSS) combined with tailor-stamping technologies are increasingly being adopted in automotive body production due to crashworthiness improvements and part weight reduction, which meet safety and energy saving demands. Recently, USIBOR^®2000 (37MnB5) steel has been added to the family of UHSS. This new material allows higher performance with respect to its predecessor USIBOR^®1500 (22MnB5). In this work, the two steels are compared for the manufacturing of an automotive B-Pillar by press-hardening with a tailored tool tempering approach. A Finite Element (FE) model has been developed for the numerical simulation of thermomechanical cycles of the press-hardening process. The FE-simulations have been performed with the aim of obtaining soft zones in the part, by varying the quenching time and the temperature of heated tools. The effects of these parameters on the mechanical properties of the part have been experimentally evaluated thanks to hardness and tensile tests performed on specimens subjected to the numerical thermo-mechanical cycles using the Geeble-3180 physical simulator. The results show that for both UHSS, an increase in quenching time leads to a decrease in hardness up to a threshold value, which is lower for the USIBOR^®1500. Moreover, higher mechanical resistance and lower elongation at break values are derived for the USIBOR^®2000 steel than for USIBOR^®1500 steel. Full article

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17 pages, 700 KiB

Open AccessReview

Causal Discovery in Manufacturing: A Structured Literature Review

by Matej Vuković and Stefan Thalmann

J. Manuf. Mater. Process. 2022, 6(1), 10; https://doi.org/10.3390/jmmp6010010 - 14 Jan 2022

Cited by 35 | Viewed by 7407

Abstract

Industry 4.0 radically alters manufacturing organization and management, fostering collection and analysis of increasing amounts of data. Advanced data analytics, such as machine learning (ML), are essential for implementing Industry 4.0 and obtaining insights regarding production, better decision support, and enhanced manufacturing quality [...] Read more.

Industry 4.0 radically alters manufacturing organization and management, fostering collection and analysis of increasing amounts of data. Advanced data analytics, such as machine learning (ML), are essential for implementing Industry 4.0 and obtaining insights regarding production, better decision support, and enhanced manufacturing quality and sustainability. ML outperforms traditional approaches in many cases, but its complexity leads to unclear bases for decisions. Thus, acceptance of ML and, concomitantly, Industry 4.0, is hindered due to increasing requirements of fairness, accountability, and transparency, especially in sensitive-use cases. ML does not augment organizational knowledge, which is highly desired by manufacturing experts. Causal discovery promises a solution by providing insights on causal relationships that go beyond traditional ML’s statistical dependency. Causal discovery has a theoretical background and been successfully applied in medicine, genetics, and ecology. However, in manufacturing, only experimental and scattered applications are known; no comprehensive overview about how causal discovery can be applied in manufacturing is available. This paper investigates the state and development of research on causal discovery in manufacturing by focusing on motivations for application, common application scenarios and approaches, impacts, and implementation challenges. Based on the structured literature review, four core areas are identified, and a research agenda is proposed. Full article

(This article belongs to the Special Issue Industry 4.0: Manufacturing and Materials Processing)

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14 pages, 7200 KiB

Open AccessArticle

Characterization of Wire-Bonding on LDS Materials and HF-PCBs for High-Frequency Applications

by Thomas Guenther, Kai Werum, Ernst Müller, Marius Wolf and André Zimmermann

J. Manuf. Mater. Process. 2022, 6(1), 9; https://doi.org/10.3390/jmmp6010009 - 11 Jan 2022

Viewed by 3293

Abstract

Thermosonic wire bonding is a well-established process. However, when working on advanced substrate materials and the associated required metallization processes to realize innovative applications, multiple factors impede the straightforward utilization of the known process. Most prominently, the surface roughness was investigated regarding bond [...] Read more.

Thermosonic wire bonding is a well-established process. However, when working on advanced substrate materials and the associated required metallization processes to realize innovative applications, multiple factors impede the straightforward utilization of the known process. Most prominently, the surface roughness was investigated regarding bond quality in the past. The practical application of wire bonding on difficult-to-bond substrates showed inhomogeneous results regarding this quality characteristic. This study describes investigations on the correlation among the surface roughness, profile peak density and bonding quality of Au wire bonds on thermoplastic and thermoset-based substrates used for high-frequency (HF) applications and other high-end applications. FR4 PCB (printed circuit board flame resitant class 4) were used as references and compared to HF-PCBs based on thermoset substrates with glass fabric and ceramic filler as well as technical thermoplastic materials qualified for laser direct structuring (LDS), namely LCP (liquid crystal polymer), PEEK (polyether ether ketone) and PTFE (polytetrafluoroethylene). These LDS materials for HF applications were metallized using autocatalytic metal deposition to enable three-dimensional structuring, eventually. For that purpose, bond parameters were investigated on the mentioned test substrates and compared with state-of-the-art wire bonding on FR4 substrates as used for HF applications. Due to the challenges of the limited thermal conductivity and softening of such materials under thermal load, the surface temperatures were matched up by thermography and the adaptation of thermal input. Pull tests were carried out to determine the bond quality with regard to surface roughness. Furthermore, strategies to increase reliability by the stitch-on-ball method were successfully applied. Full article

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31 pages, 958 KiB

Open AccessArticle

Modelling the Heating Process in the Transient and Steady State of an In Situ Tape-Laying Machine Head

by Jhonny de Sá Rodrigues, Paulo Teixeira Gonçalves, Luis Pina and Fernando Gomes de Almeida

J. Manuf. Mater. Process. 2022, 6(1), 8; https://doi.org/10.3390/jmmp6010008 - 11 Jan 2022

Cited by 3 | Viewed by 3017

Abstract

As the use of composite materials increases, the search for suitable automated processes gains relevance for guaranteeing production quality by ensuring the uniformity of the process, minimizing the amount of scrap generated, and reducing the time and energy consumption. Limitations on production by [...] Read more.

As the use of composite materials increases, the search for suitable automated processes gains relevance for guaranteeing production quality by ensuring the uniformity of the process, minimizing the amount of scrap generated, and reducing the time and energy consumption. Limitations on production by traditional means such as hand lay-up, vacuum bagging, and in-autoclave methods tend not to be as efficient when the size and shape complexity of the part being produced increases, motivating the search for alternative processes such as automated tape laying (ATL). This work aims to describe the process of modelling and simulating a composite ATL with in situ consolidation by characterizing the machine elements and using the finite differences method in conjunction with energy balances in order to create a digital twin of the process for further control design. The modelling approach implemented is able to follow the process dynamics when changes are made to the heating element and to predict the composite material temperature response, making it suitable for use as a digital twin of a production process using an ATL machine. Full article

(This article belongs to the Topic Modern Technologies and Manufacturing Systems)

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23 pages, 10366 KiB

Open AccessArticle

Significant Reduction in Energy Consumption and Carbon Emission While Improving Productivity in Laser Drilling of CFRP Sheets with a Novel Stepped Process Parameter Parallel Ring Method

by Menghui Zhu, Chao Wei, Wei Guo, Zhizhou Zhang, Jinglei Ouyang, Paul Mativenga and Lin Li

J. Manuf. Mater. Process. 2022, 6(1), 7; https://doi.org/10.3390/jmmp6010007 - 5 Jan 2022

Cited by 10 | Viewed by 3482

Abstract

Although laser drilling of carbon fibre-reinforced polymer (CFRP) composites offers the advantages of zero tool-wear and avoidance of fibre delamination compared with mechanical drilling, it consumes considerably more energy during the drilling process. This research shows that by using a new, stepped parameter [...] Read more.

Although laser drilling of carbon fibre-reinforced polymer (CFRP) composites offers the advantages of zero tool-wear and avoidance of fibre delamination compared with mechanical drilling, it consumes considerably more energy during the drilling process. This research shows that by using a new, stepped parameter parallel ring laser hole drilling method, an energy saving of 78.10% and an 18.37 gCO₂ reduction for each hole, while improving productivity by more than 300%, can be achieved in laser drilling of 6 mm diameter holes in CFRP sheets of 2 mm in thickness, compared with previous laser drilling methods under the same drilling quality. The key reason for this is an increase in energy input to the inner rings enabling more rapid removal of the material, while the lower energy input for the outer ring provides a shielding trench to reduce the heat loss into the parent material. The results are compared with single-ring laser drilling and multiple-ring laser drilling with constant processing parameters, and a discussion is given on comparing with mechanical drilling and future prospects, including a combined mechanical drilling and laser pre-scribing process. Full article

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17 pages, 5211 KiB

Open AccessArticle

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://doi.org/10.3390/jmmp6010006 - 1 Jan 2022

Cited by 9 | Viewed by 3268

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

Open AccessArticle

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://doi.org/10.3390/jmmp6010005 - 27 Dec 2021

Cited by 7 | Viewed by 2790

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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32 pages, 24409 KiB

Open AccessEditor’s ChoiceReview

Review on Additive Manufacturing of Multi-Material Parts: Progress and Challenges

by Seymur Hasanov, Suhas Alkunte, Mithila Rajeshirke, Ankit Gupta, Orkhan Huseynov, Ismail Fidan, Frank Alifui-Segbaya and Allan Rennie

J. Manuf. Mater. Process. 2022, 6(1), 4; https://doi.org/10.3390/jmmp6010004 - 27 Dec 2021

Cited by 97 | Viewed by 16039

Abstract

Additive manufacturing has already been established as a highly versatile manufacturing technique with demonstrated potential to completely transform conventional manufacturing in the future. The objective of this paper is to review the latest progress and challenges associated with the fabrication of multi-material parts [...] Read more.

Additive manufacturing has already been established as a highly versatile manufacturing technique with demonstrated potential to completely transform conventional manufacturing in the future. The objective of this paper is to review the latest progress and challenges associated with the fabrication of multi-material parts using additive manufacturing technologies. Various manufacturing processes and materials used to produce functional components were investigated and summarized. The latest applications of multi-material additive manufacturing (MMAM) in the automotive, aerospace, biomedical and dentistry fields were demonstrated. An investigation on the current challenges was also carried out to predict the future direction of MMAM processes. It was concluded that further research and development is needed in the design of multi-material interfaces, manufacturing processes and the material compatibility of MMAM parts. Full article

(This article belongs to the Special Issue Anniversary Review and Feature Papers)

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14 pages, 8877 KiB

Open AccessArticle

Development of a Low-Cost Wire Arc Additive Manufacturing System

by Miguel Navarro, Amer Matar, Seyid Fehmi Diltemiz and Mohsen Eshraghi

J. Manuf. Mater. Process. 2022, 6(1), 3; https://doi.org/10.3390/jmmp6010003 - 24 Dec 2021

Cited by 14 | Viewed by 9420

Abstract

Due to their unique advantages over traditional manufacturing processes, metal additive manufacturing (AM) technologies have received a great deal of attention over the last few years. Using current powder-bed fusion AM technologies, metal components are very expensive to manufacture, and machines are complex [...] Read more.

Due to their unique advantages over traditional manufacturing processes, metal additive manufacturing (AM) technologies have received a great deal of attention over the last few years. Using current powder-bed fusion AM technologies, metal components are very expensive to manufacture, and machines are complex to build and maintain. Wire arc additive manufacturing (WAAM) is a new method of producing metallic components with high efficiency at an affordable cost, which combines welding and 3D printing. In this work, gas tungsten arc welding (GTAW) is incorporated into a gantry system to create a new metal additive manufacturing platform. Design and build of a simple, affordable, and effective WAAM system is explained and the most frequently seen problems are discussed with their suggested solutions. Effect of process parameters on the quality of two additively manufactured alloys including plain carbon steel and Inconel 718 were studied. System design and troubleshooting for the wire arc AM system is presented and discussed. Full article

(This article belongs to the Topic Additive Manufacturing)

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41 pages, 21219 KiB

Open AccessArticle

Multi-Scale Modeling of Residual Stresses Evolution in Laser Powder Bed Fusion of Inconel 625

by Mohamed Balbaa and Mohamed Elbestawi

J. Manuf. Mater. Process. 2022, 6(1), 2; https://doi.org/10.3390/jmmp6010002 - 23 Dec 2021

Cited by 7 | Viewed by 3763

Abstract

Laser powder bed fusion exhibits many advantages for manufacturing complex geometries from hard to machine alloys such as IN625. However, a major drawback is the formation of high tensile residual stresses, and the complex relationship between the process parameters and the residual stresses [...] Read more.

Laser powder bed fusion exhibits many advantages for manufacturing complex geometries from hard to machine alloys such as IN625. However, a major drawback is the formation of high tensile residual stresses, and the complex relationship between the process parameters and the residual stresses has not been fully investigated. The current study presents multi-scale models to examine the variation of process parameters on melt pool dimensions, cyclic temperature evolutions, cooling rate, and cyclic stress generation and how they affect the stress end state. In addition, the effect of the same energy density, which is often overlooked, on the generated residual stresses is investigated. Multi-level validation is performed based on melt pool dimensions, temperature measurements with a two-color pyrometer, and finally, in-depth residual stress measurement. The results show that scan speed has the strongest effect on residual stresses, followed by laser power and hatch spacing. The results are explained in light of the non-linear temperature evolution, temperature gradient, and cooling rate during laser exposure, cooling time, and the rate during recoating time. Full article

(This article belongs to the Topic Additive Manufacturing)

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16 pages, 3235 KiB

Open AccessArticle

Laser Scanning Based Object Detection to Realize Digital Blank Shadows for Autonomous Process Planning in Machining

by Berend Denkena, Marcel Wichmann, Klaas Maximilian Heide and René Räker

J. Manuf. Mater. Process. 2022, 6(1), 1; https://doi.org/10.3390/jmmp6010001 - 22 Dec 2021

Cited by 2 | Viewed by 3475

Abstract

The automated process chain of an unmanned production system is a distinct challenge in the technical state of the art. In particular, accurate and fast raw-part recognition is a current problem in small-batch production. This publication proposes a method for automatic optical raw-part [...] Read more.

The automated process chain of an unmanned production system is a distinct challenge in the technical state of the art. In particular, accurate and fast raw-part recognition is a current problem in small-batch production. This publication proposes a method for automatic optical raw-part detection to generate a digital blank shadow, which is applied for adapted CAD/CAM (computer-aided design/computer-aided manufacturing) planning. Thereby, a laser-triangulation sensor is integrated into the machine tool. For an automatic raw-part detection and a workpiece origin definition, a dedicated algorithm for creating a digital blank shadow is introduced. The algorithm generates adaptive scan paths, merges laser lines and machine axis data, filters interference signals, and identifies part edges and surfaces according to a point cloud. Furthermore, a dedicated software system is introduced to investigate the created approach. This method is integrated into a CAD/CAM system, with customized software libraries for communication with the CNC (computer numerical control) machine. The results of this study show that the applied method can identify the positions, dimensions, and shapes of different raw parts autonomously, with deviations less than 1 mm, in 2.5 min. Moreover, the measurement and process data can be transferred without errors to different hardware and software systems. It was found that the proposed approach can be applied for rough raw-part detection, and in combination with a touch probe for accurate detection. Full article

(This article belongs to the Special Issue Progress in Digital Twin Integration for Smart Machining)

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J. Manuf. Mater. Process., Volume 6, Issue 1 (February 2022) – 26 articles

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