Research

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17 pages, 9662 KiB

Open AccessArticle

In Situ Stereo Digital Image Correlation with Thermal Imaging as a Process Monitoring Method in Vacuum-Assisted Thermoforming

by Rasoul Varedi, Bart Buffel and Frederik Desplentere

J. Manuf. Mater. Process. 2024, 8(2), 49; https://doi.org/10.3390/jmmp8020049 - 01 Mar 2024

Viewed by 947

Abstract

This experimental study probes the dynamic behaviour of a 3 mm ABS sheet during positive mould vacuum-assisted thermoforming. In this process, the sheet undergoes large and fast deformations caused by the applied vacuum and mechanical stretching by the mould. The objective is to [...] Read more.

This experimental study probes the dynamic behaviour of a 3 mm ABS sheet during positive mould vacuum-assisted thermoforming. In this process, the sheet undergoes large and fast deformations caused by the applied vacuum and mechanical stretching by the mould. The objective is to elucidate the complexities of these large, rapid, and non-isothermal deformations. The non-isothermal conditions are caused by the radiative heating of the sheet, convective heat loss to the surrounding air, and conductive heat transfer from the sheet to the mould. By utilizing stereo digital image correlation (DIC) in tandem with thermal imaging, the present study accurately maps the occurring displacement, strain, and strain rate field in relation to real-time temperature variation in the material. The study progresses to observe the ABS material from the moment it contacts the mould until it conforms to a positive 250 mm diameter semi-sphere cast aluminum mould. The DIC methods are validated by comparing thickness values derived from DIC’s principal strain directions to ultrasonic thickness gauge readings. This knowledge not only broadens the understanding of the thermo-mechanical behaviour of the material but also aids in optimizing process parameters for improved thickness uniformity in thermoformed products. Full article

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

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15 pages, 4855 KiB

Open AccessArticle

Modeling the Thermoforming Process of a Complex Geometry Based on a Thermo-Visco-Hyperelastic Model

by Ameni Ragoubi, Guillaume Ducloud, Alban Agazzi, Patrick Dewailly and Ronan Le Goff

J. Manuf. Mater. Process. 2024, 8(1), 33; https://doi.org/10.3390/jmmp8010033 - 08 Feb 2024

Viewed by 1345

Abstract

The thermoforming process is commonly used in industry for the manufacturing of lightweight, thin-walled products from a pre-extruded polymer sheet. Many simulations have been developed to simulate the process and optimize it with computer tools. The development of testing machines has simplified the [...] Read more.

The thermoforming process is commonly used in industry for the manufacturing of lightweight, thin-walled products from a pre-extruded polymer sheet. Many simulations have been developed to simulate the process and optimize it with computer tools. The development of testing machines has simplified the simulation of this type of process, allowing researchers to characterize the behavior of the material at different temperatures and for large deformation to be closer to the real conditions of the process. This paper presents the results of a study on the modeling of the thermoforming process for an industrial demonstrator made from a high-impact polystyrene (HIPS) polymer. The HIPS shows a mechanical behavior that depends on the temperature and strain rate. In such conditions, a thermo-hyper-viscoelastic constitutive model is used to replicate the thermoforming process of the industrial demonstrator using ABAQUS/Explicit. Its behavior is determined via various experimental tests: uniaxial tensile tests at different temperatures and strain rates and Dynamic Mechanical Analysis (DMA). A comparison between the numerical and experimental results is carried out for the evolution of film thickness. The paper concludes with a discussion of possible improvements to be considered for future simulations of the thermoforming process using Abaqus, which presents complex challenges in terms of contact and material modeling. Full article

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

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16 pages, 19166 KiB

Open AccessArticle

Deep Container Fabrication by Forging with High- and Low-Density Wood

by Hinako Uejima, Takashi Kuboki, Soichi Tanaka and Shohei Kajikawa

J. Manuf. Mater. Process. 2024, 8(1), 30; https://doi.org/10.3390/jmmp8010030 - 06 Feb 2024

Viewed by 1146

Abstract

This paper presents a method for applying forging to high-density wood. A cylindrical container was formed using a closed die, and the appropriate conditions for temperature and punch length were evaluated. Ulin, which is a high-density wood, and Japanese cedar, which is a [...] Read more.

This paper presents a method for applying forging to high-density wood. A cylindrical container was formed using a closed die, and the appropriate conditions for temperature and punch length were evaluated. Ulin, which is a high-density wood, and Japanese cedar, which is a low-density wood and widely used in Japan, were used as test materials. The pressing directions were longitudinal and radial based on wood fiber orientation, and the shape and density of the resulting containers were evaluated. In the case of ulin, cracks decreased by increasing the temperature, while temperature had little effect on Japanese cedar. Containers without cracks were successfully formed by using a punch of appropriate length. The density of the containers was uniform in the punch length l = 20 and 40 mm in the L-directional pressing and l = 20 mm in the R-directional pressing when using ulin, with an average density of 1.34 g/cm³. This result indicates the forging ability of ulin is high compared to that of commonly used low-density woods. In summary, this paper investigated the appropriate parameters for forging with ulin. As a result, products of more uniform density than products made by cutting were obtained. Full article

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

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21 pages, 7850 KiB

Open AccessArticle

Effect of Intermediate Path on Post-Wrinkle Initiation of the Multi-Pass Metal Spinning Process: Analysis in the Rotating Reference Frame

by Huy Hoan Nguyen, Henri Champliaud and Van Ngan Le

J. Manuf. Mater. Process. 2024, 8(1), 19; https://doi.org/10.3390/jmmp8010019 - 24 Jan 2024

Viewed by 1171

Abstract

The metal spinning process has been observed in recent major investigations carried out using finite element analysis. One interesting idea has proposed simulating a rotating disc for the simulation of the metal spinning process to reduce computational time. The development of this concept [...] Read more.

The metal spinning process has been observed in recent major investigations carried out using finite element analysis. One interesting idea has proposed simulating a rotating disc for the simulation of the metal spinning process to reduce computational time. The development of this concept is presented in this paper, including the formal mathematical transformation from the inertial frame to the rotating reference frame, specific FEM configurations with mesh sizes based on a minimized aspect ratio, a mesh convergence study, and the application of a feed rate scale. Furthermore, in the context of the rotating reference frame, the flange geometry after wrinkle initiation is investigated, including the number of peaks and their amplitudes. Using this new approach, it was found that the number of peaks gradually increases from two to eight peaks while their amplitude decreases. In the case of severe wrinkles, the number of peaks stays at four while the amplitude increases dramatically. The intermediate path proves capable of increasing the number of peaks while maintaining a low amplitude. These results will make it possible to design new paths, facilitating the production of defect-free spun parts. Full article

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

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18 pages, 6195 KiB

Open AccessEditor’s ChoiceArticle

Numerical Modelling for Efficient Analysis of Large Size Multi-Stage Incremental Sheet Forming

by Yehia Abdel-Nasser, Ninshu Ma, Sherif Rashed, Kenji Miyamoto and Hirotaka Miwa

J. Manuf. Mater. Process. 2024, 8(1), 3; https://doi.org/10.3390/jmmp8010003 - 22 Dec 2023

Viewed by 1327

Abstract

Incremental sheet forming (ISF) is an advanced flexible manufacturing process to produce complex 3D products. Unlike the conventional stamping process, ISF does not require any high cost dedicated dies. However, numerical computation for large-size ISF processes is time-consuming, and its accuracy for spring [...] Read more.

Incremental sheet forming (ISF) is an advanced flexible manufacturing process to produce complex 3D products. Unlike the conventional stamping process, ISF does not require any high cost dedicated dies. However, numerical computation for large-size ISF processes is time-consuming, and its accuracy for spring back due to unclamping tools after ISF cannot satisfy industrial demand. In this paper, an advanced numerical model considering complicated forming tool paths, trimming, and spring back was developed to efficiently simulate the multi-stage deformation phenomena of incremental sheet forming processes. Numerical modeling accuracy and efficiency are investigated considering the influence of tool path, material properties of the blank, mesh size, and boundary conditions. Through a series of case studies and comparisons with experimental results, it is observed that the numerical model with kinematics material properties and a moderate element size (5 mm) may reproduce the deformation characteristics of ISF with good accuracy and can obtain practical efficiency for a large-size ISF part. Full article

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

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19 pages, 5743 KiB

Open AccessEditor’s ChoiceArticle

Influence of Temperature on the Forming Limits of High-Strength Low Alloy, and Dual-Phase Steels

by Nikolas Woellner, Manolo L. Gipiela, Sergio Fernando Lajarin, Claudimir J. Rebeyka, Chetan P. Nikhare and Paulo V. P. Marcondes

J. Manuf. Mater. Process. 2023, 7(6), 211; https://doi.org/10.3390/jmmp7060211 - 28 Nov 2023

Viewed by 1368

Abstract

High-strength steels (HSS) appear as a good alternative to common steels to reduce vehicle weight, thus reducing fuel consumption. Despite the excellent mechanical behavior towards its lower weight, its application in industry is still limited, as manufacturing such materials suffers from limitations, especially [...] Read more.

High-strength steels (HSS) appear as a good alternative to common steels to reduce vehicle weight, thus reducing fuel consumption. Despite the excellent mechanical behavior towards its lower weight, its application in industry is still limited, as manufacturing such materials suffers from limitations, especially regarding formability. The literature shows springback to be the most common problem. Among the parameters that can be studied to minimize this problem, the temperature appears, according to the literature, to be one of the most influential parameters in minimizing springback. However, the consequence of the temperature increase on the forming limits of materials is not completely understood. This study proposes to determine the consequences of the use of the temperature rise technique in the forming limits of high-strength steels. Two different steels were studied (HSLA 350/440 and DP 350/600). To evaluate the formability, the Nakazima method was used (practical). Finite element models were made which describe the material as well as Nakazima experimental behavior. To predict the forming limit strains via the numerical method, the thickness gradient criterion was applied. The practical and computational results were compared to validate the finite element model. Four different temperature ranges were analyzed. In general, it was found that 400 °C has a negative impact on the forming limits of both steels. This negative effect was found to be due to the alloying elements, such as silicon and manganese, present in the alloy. These alloying elements take part in the increase and decrease in resistance coefficient at the elevated temperature. For HSLA 350/440 steel, the forming limit strain decreased with an increase in temperature up to 600 °C and then increased at 800 °C; whereas for DP 350/600 steel, the forming limit strain decreased till 400 °C and then increased for 600 °C and 800 °C. Another factor which might have contributed to the behavior of the DP steel is the interaction of hard martensite with soft ferrite phase. Full article

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

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12 pages, 5325 KiB

Open AccessArticle

Processing of the Ti25Ta25Nb3Sn Experimental Alloy Using ECAP Process for Biomedical Applications

by Celso Bortolini, Jr., João Pedro Aquiles Carobolante, Ilana Timokhina, Angelo Caporalli Filho and Ana Paula Rosifini Alves

J. Manuf. Mater. Process. 2023, 7(6), 201; https://doi.org/10.3390/jmmp7060201 - 10 Nov 2023

Viewed by 1339

Abstract

The development of titanium-β alloys for biomedical applications is associated with the addition of alloying elements or the use of processing techniques to obtain suitable bulk properties. The Ti25Ta25Nb3Sn alloy has been highlighted for its mechanical properties and biocompatibility. To further enhance the [...] Read more.

The development of titanium-β alloys for biomedical applications is associated with the addition of alloying elements or the use of processing techniques to obtain suitable bulk properties. The Ti25Ta25Nb3Sn alloy has been highlighted for its mechanical properties and biocompatibility. To further enhance the properties of titanium alloys for biomedical applications, equal channel angular pressing (ECAP) was used due to its capability of refining the microstructure of the alloy, leading to improved mechanical properties without significant changes in Young’s modulus. This study aims to evaluate the impact of ECAP on the microstructure of the Ti-25Sn-25Nb-3Nb alloy and investigate the correlation between the microstructure, mechanical properties, and corrosive behavior. Grain refinement was achieved after four ECAP passes, with an average grain diameter of 395 nm and a non-homogeneous structure, and microhardness was slightly increased from 193 to 212 HV after four ECAP passes. The thermomechanical aspects of the ECAP processing have led to the formation of a metastable α″ phase during the first two passes, while after four passes, the structure was composed only of the β phase. The corrosion resistance of the alloy was increased after four passes, presenting the best results in terms of the improvement of passivation corrosion density. Full article

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

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25 pages, 17661 KiB

Open AccessArticle

Microstructural and Mechanical Analysis of Seamless Pipes Made of Superaustenitic Stainless Steel Using Cross-Roll Piercing and Elongation

by Alberto Murillo-Marrodán, Yury Gamin, Liudmila Kaputkina, Eduardo García, Alexander Aleshchenko, Hamed Aghajani Derazkola, Alexey Pashkov and Evgeniy Belokon

J. Manuf. Mater. Process. 2023, 7(5), 185; https://doi.org/10.3390/jmmp7050185 - 14 Oct 2023

Cited by 1 | Viewed by 1824

Abstract

The cross-roll piercing and elongation (CPE) is a forming process performed at high temperatures and high strain rates. The final product quality is strongly dependent on its microstructure. In this study, a finite element method (FEM) model was developed to better understand plastic [...] Read more.

The cross-roll piercing and elongation (CPE) is a forming process performed at high temperatures and high strain rates. The final product quality is strongly dependent on its microstructure. In this study, a finite element method (FEM) model was developed to better understand plastic deformation effects on microstructure during CPE and to analyze alternative thermo-mechanical processing routes. Specific models were used to simulate dynamic and meta-dynamic recrystallization (DRX and MDRX) for the processing of superaustenitic stainless steel (SASS). In addition, the CPE of SASS was investigated experimentally. The microstructure, mechanical properties, and chemical changes of the final product were assessed using optical microscopy, hardness testing, X-ray diffraction, and SEM-EDS. The results revealed higher temperatures and strain rates in the exterior area of the shell after piercing, and MDRX occurred in the whole thickness. However, an average grain size reduction of 13.9% occurred only in the shell middle and inner diameters. During elongation, the highest values of the strain rate and DRX were observed in the inner region, exhibiting a grain size reduction of 38%. Spread in terms of grain size and grain shape anisotropy was found to be less accentuated for tube samples as compared to the pierced shells. Full article

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

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19 pages, 5322 KiB

Open AccessArticle

Improving Material Formability and Tribological Conditions through Dual-Pressure Tube Hydroforming

by Gracious Ngaile and Mauricio Avila

J. Manuf. Mater. Process. 2023, 7(4), 126; https://doi.org/10.3390/jmmp7040126 - 02 Jul 2023

Viewed by 1061

Abstract

Dual-pressure tube hydroforming (THF) is a tube-forming process that involves applying fluid pressure to a tube’s inner and outer surfaces to achieve deformation. This study investigates the effect of dual-pressure loading paths on material formability and tribological conditions. Specifically, pear-shaped and triangular cross-sectional [...] Read more.

Dual-pressure tube hydroforming (THF) is a tube-forming process that involves applying fluid pressure to a tube’s inner and outer surfaces to achieve deformation. This study investigates the effect of dual-pressure loading paths on material formability and tribological conditions. Specifically, pear-shaped and triangular cross-sectional parts were formed using dual-pressure modes where fluid pressure on the inside of the tubular blank was alternated with pressure on the outside surface of the tubular blank, causing the tube to expand/stretch and contract. During expansion, the tube conformed to the die’s cavity, while during contraction, the contact area between the die and the workpiece reduced, leading to decreased friction stress at the tube–die interface. Additionally, the reversal of pressure loadings caused the tubular blank to buckle, altering the stress state and potentially increasing local shear stress, improving material formability. Dual-pressure THF has demonstrated that the pressure loading paths chosen can substantially influence material formability. Comparing the geometries of parts formed by dual-pressure THF and conventional THF shows a significant increase in the protrusion height of both the pear-shaped and triangular specimens using dual-pressure THF. Full article

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

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24 pages, 7107 KiB

Open AccessArticle

A Geometry-Dependent Void Closure Model Considering Void Deformation and Orientation Changes during Hot Metal Formation

by Jihyun Kim, Joonhee Park, Yosep Kim, Hyukjoon Kwon and Naksoo Kim

J. Manuf. Mater. Process. 2023, 7(3), 117; https://doi.org/10.3390/jmmp7030117 - 20 Jun 2023

Viewed by 1371

Abstract

In this paper, a void closure model applicable to the general hot forming process has been proposed. Through the representative volume element (RVE) method, the influences of void shape, orientation, and stress state on void closure tendency were analysed. The void closure model [...] Read more.

In this paper, a void closure model applicable to the general hot forming process has been proposed. Through the representative volume element (RVE) method, the influences of void shape, orientation, and stress state on void closure tendency were analysed. The void closure model was established so that it could consider these cross effects. The model calculates the changing void radius and orientation during deformation by considering the rate of change of the parameters affecting void deformation with respect to the effective strain. The model predicted the void closure tendency well on the RVE scale and predicted the void closure adequately in a multi-stage process with random voids. The results were compared with the stress-triaxiality-based (STB) model, which showed that the void closure model proposed in this study is applicable in general situations. A cogging process was analysed, and the degree of void closure at the end of each pass was compared with the calculated results of the void closure model. For the experimental verification of the proposed model, spherical and ellipsoid voids were placed in a rectangular specimen, and the radii of the voids after compression were measured. The measurement results were compared with the calculation results of the proposed model. Full article

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

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18 pages, 6801 KiB

Open AccessArticle

Theoretical Analysis of Rolling Force during Cold Rolling with Roll Crossing and Shifting System

by Abdulrahman Aljabri, Hasan Tibar, Essam R. I. Mahmoud, Hamad Almohamadi, Feijun Qu and Zhengyi Jiang

J. Manuf. Mater. Process. 2023, 7(3), 104; https://doi.org/10.3390/jmmp7030104 - 24 May 2023

Cited by 4 | Viewed by 2761

Abstract

A precise prediction of the rolling force is critical to ensure the quality of the final product, especially in the cold rolling of thin strips. Based on this, a new mathematical model is developed to work out the rolling force when considering the [...] Read more.

A precise prediction of the rolling force is critical to ensure the quality of the final product, especially in the cold rolling of thin strips. Based on this, a new mathematical model is developed to work out the rolling force when considering the roll crossing angle and work roll shifting values at speed ratios of 1.1, 1.2 and 1.3. An iterative method was used to indicate the contact area shape, from which the rolling force was automatically calculated using the Matlab™ code for the cases of work roll cross angles of 0.5° and 1°. Experimental measurements and analysis were carried out to validate the theoretical calculations. The result shows that the theoretical analysis and experimental results are in good agreement, which indicates that the developed theoretical model can predict the rolling force well with a consideration of roll crossing during the cold rolling process. Full article

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

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16 pages, 2278 KiB

Open AccessArticle

Numerical Investigation of Step Size Effect on Formability of 2024-T3 Aluminum in Incremental Forming

by Tyler J. Grimm, Filipe Colombini and Ihab Ragai

J. Manuf. Mater. Process. 2023, 7(2), 70; https://doi.org/10.3390/jmmp7020070 - 19 Mar 2023

Cited by 1 | Viewed by 1621

Abstract

Incremental forming (IF) is an advanced manufacturing process in which a forming tool locally deforms sheet material into a desired geometry through successive passes at incremental depths. An inherent benefit to the IF process is its formability improvement over conventional stamping; however, further [...] Read more.

Incremental forming (IF) is an advanced manufacturing process in which a forming tool locally deforms sheet material into a desired geometry through successive passes at incremental depths. An inherent benefit to the IF process is its formability improvement over conventional stamping; however, further enhancements will enable the forming of increasingly complex geometries. To progress the IF process towards heavy industrial use, the modeling of such processes must be further developed. Single point incremental forming (SPIF) of AA2024-T3 was modeled herein utilizing explicit formulations. The model geometry featured a nominally rectangular-shaped clamping region. A friction factor was experimentally determined and utilized within the model, which is a novel addition to this work. Formability was determined and forming limit diagrams were composed. It was found that the present model shows greater formability and underestimates plastic strain compared to experimental testing. The generation of forming limit diagrams for this material processed by IF is also a novel addition to this field. Full article

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

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13 pages, 11816 KiB

Open AccessArticle

An Experimental and Numerical Study on Aluminum Alloy Tailor Heat Treated Blanks

by Rui Pereira, Nuno Peixinho, Vítor Carneiro, Delfim Soares, Sara Cortez, Sérgio L. Costa and Vítor Blanco

J. Manuf. Mater. Process. 2023, 7(1), 16; https://doi.org/10.3390/jmmp7010016 - 04 Jan 2023

Cited by 1 | Viewed by 1703

Abstract

Information is presented on the conceptualization, experimental study, and numerical process simulation of tailor heat treated aluminum alloy blanks. This concept is intended to improve the forming behavior of aluminum parts in challenging conditions. The implementation requires precise control of laser heat treatment [...] Read more.

Information is presented on the conceptualization, experimental study, and numerical process simulation of tailor heat treated aluminum alloy blanks. This concept is intended to improve the forming behavior of aluminum parts in challenging conditions. The implementation requires precise control of laser heat treatment parameters within a suitable industrial framework. The study details material properties, heat treatment parameters, and experimental results for the strength and elongation properties of an AA6063-T6 aluminum alloy. Constitutive modeling is applied using the Hocket–Sherby equation, which allowed us to establish a correlation between laser heat treatment maximum temperature and the corresponding material softening degree. Based on the generated flow stress–strain curves, a numerical simulation of a representative case study was performed with Abaqus finite element software highlighting potential improvements of tailor heat treated blanks (THTB). The influence and effectiveness of heat-affected zone (HAZ) dimensions and material softening were analyzed. Full article

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

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23 pages, 8807 KiB

Open AccessArticle

Springback Behavior of Aluminum/Polypropylene/Aluminum Sandwich Laminates

by Caroline K. Kella and Pankaj K. Mallick

J. Manuf. Mater. Process. 2022, 6(6), 152; https://doi.org/10.3390/jmmp6060152 - 23 Nov 2022

Cited by 2 | Viewed by 2922

Abstract

The springback of sheet metals after forming has been widely studied for decades using numerical and experimental methods. Many of these springback studies involve aluminum alloys. This study aims to understand the springback behavior of aluminum-polypropylene-aluminum laminates as they are being used increasingly [...] Read more.

The springback of sheet metals after forming has been widely studied for decades using numerical and experimental methods. Many of these springback studies involve aluminum alloys. This study aims to understand the springback behavior of aluminum-polypropylene-aluminum laminates as they are being used increasingly in automotive and other applications because of their weight saving potential. A finite element model of the draw bending of a U-channel based on Numisheet’93 benchmark study is built using LS-DYNA. First, the model is validated and studied for springback prediction of single AA5182-O aluminum alloy sheets, and then it is extended to the study of the springback behaviors of AA5182-O/polypropylene/AA5182-O laminates with various combinations of core and skin thicknesses. The numerical model is also validated by experiment. Effects of various tool design and process parameters, such die radius, punch radius and blank holder force, on the springback of the sandwich laminates are studied. The effect of numerical modeling parameters is also considered. Full article

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

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18 pages, 3065 KiB

Open AccessArticle

Characterisation of Fibre Bundle Deformation Behaviour—Test Rig, Results and Conclusions

by Andreas Borowski, Benjamin Gröger, René Füßel and Maik Gude

J. Manuf. Mater. Process. 2022, 6(6), 146; https://doi.org/10.3390/jmmp6060146 - 17 Nov 2022

Viewed by 1596

Abstract

Deformation of continuous fibre reinforced plastics during thermally-assisted forming or joining processes leads to a change of the initial material structure. The load behaviour of composite parts strongly depends on the resultant material structure. The prediction of this material structure is a challenging [...] Read more.

Deformation of continuous fibre reinforced plastics during thermally-assisted forming or joining processes leads to a change of the initial material structure. The load behaviour of composite parts strongly depends on the resultant material structure. The prediction of this material structure is a challenging task and requires a deep knowledge of the material behaviour above melting temperature and the occurring complex forming phenomena. Through this knowledge, the optimisation of manufacturing parameters for a more efficient and reproducible process can be enabled and are in the focus of many investigations. In the present paper, a simplified pultrusion test rig is developed and presented to investigate the deformation behaviour of a thermoplastic semi-finished fiber product in a forming element. Therefore, different process parameters, like forming element temperature, pulling velocity as well as the forming element geometry, are varied. The deformation behaviour in the forming zone of the thermoplastic preimpregnated continuous glass fibre-reinforced material is investigated by computed tomography and the resultant pulling forces are measured. The results clearly show the correlation between the forming element temperature and the resulting forces due to a change in the viscosity of the thermoplastic matrix and the resulting fiber matrix interaction. In addition, the evaluation of the measurement data shows which forming forces are required to change the shape of the thermoplastic unidirectional material with a rectangular cross-section to a round one. Full article

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

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24 pages, 8986 KiB

Open AccessArticle

Process-Integrated Lubrication in Sheet Metal Forming

by Roland Lachmayer, Bernd-Arno Behrens, Tobias Ehlers, Philipp Müller, Philipp Althaus, Marcus Oel, Ehsan Farahmand, Paul Christoph Gembarski, Hendrik Wester and Sven Hübner

J. Manuf. Mater. Process. 2022, 6(5), 121; https://doi.org/10.3390/jmmp6050121 - 14 Oct 2022

Cited by 8 | Viewed by 2349

Abstract

The deep-drawability of a sheet metal blank is strongly influenced by the tribological conditions prevailing in a deep-drawing process. Therefore, new methods to influence the tribology represent an important research topic. In this work, the application of a process-integrated lubrication in a deep-drawing [...] Read more.

The deep-drawability of a sheet metal blank is strongly influenced by the tribological conditions prevailing in a deep-drawing process. Therefore, new methods to influence the tribology represent an important research topic. In this work, the application of a process-integrated lubrication in a deep-drawing process is investigated. Most promising geometries of the lubrication channels and outlet openings are first identified by means of numerical simulation at the example of a demonstrator process. Cylindrical test specimens with the specified channel geometries are additively manufactured and installed in a strip drawing test stand. Additive manufacturing enables the possibility of manufacturing complex channel geometries which cannot be manufactured by conventional methods. A hydraulic metering device for conveying lubricant is connected to the cylindrical test specimens. Thus, hydraulically lubricated strip drawing tests are performed. The tests are evaluated according to the force curves and the fluid mechanical buildup of pressure cushion. The performance of process-integrated lubrication is thus analyzed and evaluated. By means of a coupled forming and SPH simulation, the lubrication channels could be optimally designed. From the practical tests, it could be achieved that the drawing force decreases up to 27% with pressure cushion build up. In this research, a hydraulic lubrication in the area of highest contact normal stresses is the most optimal process parameter regarding friction reduction. Full article

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

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23 pages, 10032 KiB

Open AccessArticle

Physical Simulation of Laser Surface Treatment to Study Softening Effect on Age-Hardened Aluminium Alloys

by Maria Emanuela Palmieri and Luigi Tricarico

J. Manuf. Mater. Process. 2022, 6(3), 64; https://doi.org/10.3390/jmmp6030064 - 10 Jun 2022

Cited by 2 | Viewed by 2406

Abstract

The automotive industry is interested in manufacturing components with tailored mechanical properties. To this end, advanced heating treatments can be exploited to obtain the so-called Tailored Heat-Treated Blanks (THTB). However, mechanical properties are strongly affected by the process parameters of heating treatments, which [...] Read more.

The automotive industry is interested in manufacturing components with tailored mechanical properties. To this end, advanced heating treatments can be exploited to obtain the so-called Tailored Heat-Treated Blanks (THTB). However, mechanical properties are strongly affected by the process parameters of heating treatments, which require a preliminary design. Physical simulation can be a decisive tool in this phase to obtain useful information at the laboratory scale, even when heat treatments such as those carried out with laser technologies impose high heating and cooling rates on the material. This work uses physical simulation to investigate the changes in strength and ductility caused by laser heat treatment (LHT) on aluminum alloys hardened by aging; the methodology was implemented on the EN AW 6082 T6 alloy. First, a finite-element (FE) transient thermal model was developed to simulate LHT by varying the process parameters (laser power/peak temperature and treatment speed). Second, the resulting thermal cycles were physically simulated by means of the Gleeble 3180 system. Third, the strength and the ductility of physically simulated specimens were evaluated through micro-hardness and tensile tests; to study aging effects, investigations were performed both (i) right after Gleeble tests (samples in the supersaturated solid state, i.e., as-physically simulated (APS) state) and (ii) after one week from Gleeble tests (aged specimens—T4 state). The obtained results show that there are peak temperatures that guarantee maximum softening levels for each investigated state (T4 and APS). The optimal peak temperature ranges are in agreement with the data in the literature, demonstrating that the proposed methodology is suitable for the study of softening phenomena on aging-hardened aluminum alloys. Full article

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

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Review

Jump to: Research

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 25 | Viewed by 16894

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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