Journal articles: 'Sheet metal forming processes'

1

Tekkaya, A. Erman, Michael Trompeter, and Jorg Witulski. "Innovative sheet metal-forming processes." International Journal of Mechatronics and Manufacturing Systems 1, no. 2/3 (2008): 157. http://dx.doi.org/10.1504/ijmms.2008.020502.

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Hardt, David E. "Closed-Loop Sheet Metal Forming Processes." IFAC Proceedings Volumes 25, no. 28 (October 1992): 187–92. http://dx.doi.org/10.1016/s1474-6670(17)49490-0.

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Schneider, Thomas, and Marion Merklein. "Sheet-Bulk Metal Forming of Preformed Sheet Metal Parts." Key Engineering Materials 473 (March 2011): 83–90. http://dx.doi.org/10.4028/www.scientific.net/kem.473.83.

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Due to ecological and economic challenges there is a rising demand on closely-tolerated complex functional components. Regarding short process chains and improved mechanical properties conventional forming processes are often limited. A promising approach to meet these requirements can be seen in the combination of traditional sheet and bulk metal forming processes, to form sheet metals out of the sheet plane with typical bulk forming operations. The challenge of applying conventional bulk forming operations on sheet metal is the interaction between regions of high and low deformation, which is largely unknown in literature. To analyze this topic fundamentally, a process combination of deep drawing and upsetting is developed for manufacturing tooth-like elements at pre-drawn cups. To fully understand material flow out of the sheet plane into the tooth cavity and to identify and qualify process factors depending on the functional elements´ geometry and friction, a single upsetting stage forming a simplified model of the blank is virtually analyzed with finite-element simulation. By inhibiting the forming history of the pre-drawn blank, the upsetting process can be investigated without interactions with a previous deep drawing operation.

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GROCHE, P., and C. KLOEPSCH. "SHEET METAL FORMING PROCESSES AT ELEVATED TEMPERATURES." Journal of Advanced Manufacturing Systems 07, no. 02 (December 2008): 307–11. http://dx.doi.org/10.1142/s0219686708001401.

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On one hand lightweight sheet materials are characterized by high specific strength but on the other hand, they are limited in the design of sheet metal products. To extend the range of producible geometries, special forming processes at elevated temperatures have been developed. For describing the forming behavior at elevated temperatures or to design forming processes, the knowledge of relevant system parameters like flow stress, friction conditions and contact heat transmission coefficient is assumed. Additionally experimental results are presented to highlight the potential of sheet metal forming processes at elevated temperatures.

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Hattalli, Vinod Laxman, and Shivashankar R. Srivatsa. "Sheet Metal Forming Processes – Recent Technological Advances." Materials Today: Proceedings 5, no. 1 (2018): 2564–74. http://dx.doi.org/10.1016/j.matpr.2017.11.040.

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Q. Nadeem, Q. Nadeem, W. J. Seong W. J. Seong, and S. J. Na S. J. Na. "Process designing for laser forming of circular sheet metal." Chinese Optics Letters 10, no. 2 (2012): 021405–21407. http://dx.doi.org/10.3788/col201210.021405.

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Tisza, Miklós. "Advanced Materials in Sheet Metal Forming." Key Engineering Materials 581 (October 2013): 137–42. http://dx.doi.org/10.4028/www.scientific.net/kem.581.137.

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In this paper, some recent developments in materials applied in sheet metal forming processes will be overviewed mainly from the viewpoint of automotive industry as one of the most important application fields. If we consider the main requirements in the automotive industry we can state that there are very contradictory demands on developments. Better performance with lower consumption and lower harmful emission, more safety and comfort are hardly available simultaneously with conventional materials and conventional manufacturing processes. These requirements are the main driving forces behind the material and technological developments in sheet metal forming: application of high strength steels, low weight light alloys and the appropriate non-conventional forming processes are the main target fields of developments summarized in this paper.

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Nurcheshmeh, M., D. Green, C. Byrne, and A. Habib. "Prediction of Sheet Metal Forming Limits in Multistage Forming Processes." IOP Conference Series: Materials Science and Engineering 418 (September 21, 2018): 012045. http://dx.doi.org/10.1088/1757-899x/418/1/012045.

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Loukaides, E. G., and J. M. Allwood. "Automatic design of sheet metal forming processes by “un-forming”." International Journal of Mechanical Sciences 113 (July 2016): 61–70. http://dx.doi.org/10.1016/j.ijmecsci.2016.04.008.

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Allwood, J. M., and D. R. Shouler. "Paddle Forming: A Novel Class of Sheet Metal Forming Processes." CIRP Annals 56, no. 1 (2007): 257–60. http://dx.doi.org/10.1016/j.cirp.2007.05.060.

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HEO, SEONG-CHAN, TAE-WAN KU, JEONG KIM, BEOM-SOO KANG, and WOO-JIN SONG. "APPLICATION OF FORMING LIMIT CRITERIA BASED ON PLASTIC INSTABILITY CONDITION TO METAL FORMING PROCESS." International Journal of Modern Physics B 22, no. 31n32 (December 30, 2008): 5680–85. http://dx.doi.org/10.1142/s0217979208051005.

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Metal forming processes such as hydroforming and sheet metal forming using tubular material and thin sheet metal have been widely used in lots of industrial fields for manufacturing of various parts that could be equipped with mechanical products. However, it is not easy to design sequential processes properly because there are various design variables that affect formability of the parts. Therefore preliminary evaluation of formability for the given process should be carried out to minimize time consumption and development cost. With the advances in finite element analysis technique over the decades, the formability evaluation using numerical simulation has been conducted in view of strain distribution and final shape. In this paper, the application of forming limit criteria is carried out for the tube hydroforming and sheet metal forming processes using theoretical background based on plastic instability conditions. Consequently, it is confirmed that the local necking and diffuse necking criteria of sheet are suitable for formability evaluation of both hydroforming and sheet metal forming processes.

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Jung, Dong Won. "Quadrilateral Shape Rib Forming by Roll Forming Process." Applied Mechanics and Materials 878 (February 2018): 296–301. http://dx.doi.org/10.4028/www.scientific.net/amm.878.296.

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The roll forming is one of the simplest manufacturing processes for meeting the continued needs of various industries. The roll forming is increasingly used in the automotive industry to form High Strength Steel (HSS) and Advanced High Strength Steel (AHSS) for making structural components. In order to reduce the thinning of the sheet product, traditionally the roll forming has been suggested instead of the stamping process. The increased product performance, higher quality, and the lowest cost with other advantages have made roll forming processes suitable to form any shapes in the sheets. In this numerical study, a Finite Element Method is applied to estimate the stress, strain and the thickness distribution in the metal sheet with quadrilateral shape, ribs formed by the 11 steps roll forming processes using a validated model. The metal sheet of size 1,000 × 662 × 1.6 mm taken from SGHS steel was used to form the quadrilateral shape ribs on it by the roll forming process. The simulation results of the 11 step roll forming show that the stress distribution was almost uniform and the strain distribution was concentrated on the ribs. The maximum thinning strain was observed in the order of 15.5 % in the middle rib region possibly due to the least degree of freedom of the material.

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Kopp, R., C. Wiedner, and A. Meyer. "Flexibly Rolled Sheet Metal and Its Use in Sheet Metal Forming." Advanced Materials Research 6-8 (May 2005): 81–92. http://dx.doi.org/10.4028/www.scientific.net/amr.6-8.81.

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Light weight construction is a construction philosophy which aims at maximum weight reduction. Reasons for light weight construction can be very diverse. One main cause can be to improve fuel efficiency. This can be achieved by use of load optimised sheet thicknesses. Another reason can be the increasing demands on crash performances by optimisation of local properties. This paper presents two production processes of flexibly rolled blanks, one with longitudinal and the other one with latitudinal thickness transitions. Both of them have been developed at the Institute of Metal Forming (IBF) and yet found their way into series production. The potential of these processes is already proved by a large range of products, especially in automotive industries. Some special deep drawing tests with flexibly rolled blanks have been conducted and their results are presented. Also process simulation has been carried out at the IBF and will be explained. One possibility with regard to optimise these products is shortly introduced. Completing this paper an outlook is given.

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Maia, Ana, Marta C. Oliveira, António Andrade-Campos, and Luís F. Menezes. "Sensitivity Analysis for Numerical Sheet Metal Forming Processes." Key Engineering Materials 651-653 (July 2015): 1369–74. http://dx.doi.org/10.4028/www.scientific.net/kem.651-653.1369.

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Sheet Metal Forming is a widely used process in industry. However, it is also an expensive onedue to the diversity and complexity of methodologies used to obtain the adequate tools combination.In fact, even though there is already finite element based software to compute the final shape of aformed sheet from a given tool, there is no efficient procedure to predict the inverse problem: the toolgeometry from the formed component final shape.The final aim of this work is to improve the current trial-and-error process for the inverse problem.To achieve this objective, an integrated approach for tools geometry manipulation is presented, basedon the parametric NURBS description of the tools surface. This is applied to perform a sensitivityanalysis in order to evaluate the effect of numerical noise and small disturbances on the tools designvariables in the final formed sheet. Furthermore, the robustness of the proposed approach is evaluatedusing two parts with distinct complexity.

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Oliveira, Marta C., and José V. Fernandes. "Modelling and Simulation of Sheet Metal Forming Processes." Metals 9, no. 12 (December 17, 2019): 1356. http://dx.doi.org/10.3390/met9121356.

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Numerical simulation of sheet metal forming processes has become an indispensable tool for the design of components and their forming process, in industries ranging from the automotive, to the aeronautics, packing and household appliances [...]

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Seo, Y. R. "Electromagnetic blank restrainer in sheet metal forming processes." International Journal of Mechanical Sciences 50, no. 4 (April 2008): 743–51. http://dx.doi.org/10.1016/j.ijmecsci.2007.11.008.

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Ahmed, Mohd, G. S. Sekhon, and Devender Singh. "Finite Element Simulation of Sheet Metal Forming Processes." Defence Science Journal 55, no. 4 (October 1, 2005): 389–401. http://dx.doi.org/10.14429/dsj.55.2002.

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Behrens, Bernd-Arno, and Philipp Lau. "Key performance indicators for sheet metal forming processes." Production Engineering 2, no. 1 (December 4, 2007): 73–78. http://dx.doi.org/10.1007/s11740-007-0076-y.

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Galanulis, Konstantin, Stephanie Adolf, and Harald Friebe. "Optical 3D Metrology for Optimization of Sheet Metal Forming Processes." Key Engineering Materials 639 (March 2015): 3–11. http://dx.doi.org/10.4028/www.scientific.net/kem.639.3.

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3D optical metrology methods are increasingly used in the research of sheet metal materials and in sheet metal production processes. Optical measuring systems are implemented in different process stages, including design, sheet metal material research and component development, tool making and production as well as series accompanying quality control.Today’s development processes are initially driven from computational methods. Especially for the development of sheet metal components the numerical forming simulation is an important tool. However, performing a reliable forming simulation requires accurate input parameters like 3D geometry data for meshing, material parameters and boundary conditions which can be obtained with optical measuring systems. Further on the validation of these numerical simulations is supported with optical full-field sheet metal forming analysis.In the tool manufacturing phase 3D measurement data contributes in reducing the time frame for CNC machining processes, for the try-out phase, future tool reproduction as well as for repair and maintenance.With automated 3D measuring solutions series accompanying quality control is performed to determine tool wear and to shorten the response time if problems in the production occur.This paper is extending past work [1] and discusses today’s contribution of optical 3D measuring techniques in sheet metal component development and production, covering the areas of determining input parameters for sheet metal forming simulations and its validation, tool manufacturing, including the try-out, and production quality control using automated optical measurement machines.

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Jeswiet, J. "Asymmetric Incremental Sheet Forming." Advanced Materials Research 6-8 (May 2005): 35–58. http://dx.doi.org/10.4028/www.scientific.net/amr.6-8.35.

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The use of computers in manufacturing has enabled the development of several new sheet metal forming processes. This paper describes modifications that have been made to traditional forming methods such as conventional spinning and shear forming, where deformation is localized. Recent advances have enabled this localized deformation to be accurately controlled and studied. Current developments have been focused on forming asymmetric parts using CNC technology, without the need for costly dies. Asymmetric Incremental Forming has the potential to revolutionize sheet metal forming, making it accessible to all levels of manufacturing.

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Salfeld, Valerian, Richard Krimm, Sven Hübner, Thorsten Matthias, and Milan Vucetic. "Sheet-Bulk Metal Forming of Symmetric and Asymmetric Parts." Advanced Materials Research 769 (September 2013): 229–36. http://dx.doi.org/10.4028/www.scientific.net/amr.769.229.

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The unique process of sheet-bulk metal forming (SBMF) represents a combination of sheet and bulk metal forming by inducing a three-dimensional material flow in sheet metals in a single forming stage. Within this paper two different applications of sheet-bulk metal forming are demonstrated. Hereby two different combined drawing and upsetting processes to realize parts with symmetrically and asymmetrically arranged functional elements are analysed. Finally, this contribution introduces a new machine technique which provides an improvement of the working accuracy of a forming machine and thus has a positive influence on the parts quality. The idea is to use electromagnetic ram guidance to counteract the displacement of the ram due to horizontal forming forces while forming of asymmetric parts.

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Vahdati, Mehdi, Ramezanali Mahdavinejad, and Saeid Amini. "Investigation of the ultrasonic vibration effect in incremental sheet metal forming process." Proceedings of the Institution of Mechanical Engineers, Part B: Journal of Engineering Manufacture 231, no. 6 (April 8, 2015): 971–82. http://dx.doi.org/10.1177/0954405415578579.

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The mechanism of incremental sheet metal forming is based on plastic and localized deformation of sheet metal. The sheet metal is formed using a hemispherical-head tool in accordance with the path programmed into the computer numerical control milling machine controller. Experimental and numerical analyses have been performed previously on the application of ultrasonic vibration to various metal forming processes. However, thus far, the effects of ultrasonic vibration on incremental sheet metal forming have not been investigated. This article presents the process of design, analysis, manufacture and testing of a vibrating forming tool for the development of ultrasonic vibration–assisted incremental sheet metal forming. The results obtained from modal analysis and natural frequency measurement of the vibrating tool confirmed the emergence of a longitudinal vibration mode and resonance phenomenon in the forming tool. Then, the effect of ultrasonic vibration on incremental sheet metal forming was studied. The obtained experimental results from the straight groove test on Al 1050-O sheet metals showed that ultrasonic vibration led to decrease in the following parameters as compared with conventional incremental sheet metal forming: applied force on forming tool axis, spring-back and surface roughness of formed sample.

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23

Dehghan, Mojtaba, Fathallah Qods, and Mahdi Gerdooei. "Effect of Accumulative Roll Bonding Process with Inter-Cycle Heat Treatment on Microstructure and Microhardness of AA1050 Alloy." Key Engineering Materials 531-532 (December 2012): 623–26. http://dx.doi.org/10.4028/www.scientific.net/kem.531-532.623.

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Processes with severe plastic deformation (SPD) may be deﬁned as metal forming processes in which ultra-large plastic strain is introduced into a bulk metal in order to create ultra-ﬁne grained (UFG) metals. Accumulative roll bonding (ARB) is a SPD process that may be deﬁned as multisteps rolling process in order to create high strength metals with UFG structure. In this study, ARB process with inter-cycle annealing is carried out on the commercial purity aluminium (AA1050) sheet up to 13 cycles. The purpose of the present study is investigation of microhardness behavior and microstructural evolution in the ARB processed AA1050 sheet. Micro-Vickers hardness measurement is carried out throughout thickness of the ARB processed sheets. In addition, with increasing ARB cycles the grains size is reduced in nanometer level.

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Merklein, Marion, A. Erman Tekkaya, Alexander Brosius, Simon Opel, Lukas Kwiatkowski, Björn Plugge, and Sebastian Schunk. "Machines and Tools for Sheet-Bulk Metal Forming." Key Engineering Materials 473 (March 2011): 91–98. http://dx.doi.org/10.4028/www.scientific.net/kem.473.91.

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The demand on closely-tolerated and complex functional components in the automotive sector, like e.g. synchronizer rings, leads to the development of a new process-class named “sheet-bulk metal forming”. Within this technology bulk metal forming operations are applied on sheet metals. In the following two novel approaches considering machines and tools for sheet-bulk metal forming are presented. The first approach aims on a technology based on rolling, which is suitable for mass production. The second one is an incremental forming solution for low batch production. Both machine concepts allow the application of different forming strategies to manufacture individual tailored semi-finished products in term of a pre-distribution of material. These products feature variable sheet thicknesses and mechanical properties, which can be adapted to their case of applica-tion. Depending on the individual batch size, the blanks can be finished to functional parts by sub-sequent forming processes like deep drawing and upsetting, extrusion or incremental forming. In this paper the case of an incremental tooth-forming is mainly considered. Forming sequences and resulting loads are modeled and calculated by finite elements simulations for all discussed processes to serve as a basis for the design and dimensioning of the machine components and forming tools.

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Wilson, W. R. D. "Tribology in Cold Metal Forming." Journal of Manufacturing Science and Engineering 119, no. 4B (November 1, 1997): 695–98. http://dx.doi.org/10.1115/1.2836811.

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The tribological aspects of cold metal forming processes is reviewed. Special attention is paid to rolling and stamping operations as these are typical of bulk forming and sheet forming processes, respectively, and are the most important commercial processes. It is shown that a better understanding of tribological fundamentals, as applied to cold metal forming, can result in better lubrication systems and process models.

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Sieczkarek, Peter, Lukas Kwiatkowski, A. Erman Tekkaya, Eugen Krebs, Dirk Biermann, Wolfgang Tillmann, and Jan Herper. "Improved Tool Surfaces for Incremental Bulk Forming Processes of Sheet Metals." Key Engineering Materials 504-506 (February 2012): 975–80. http://dx.doi.org/10.4028/www.scientific.net/kem.504-506.975.

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Sheet-bulk metal forming is a process used to manufacture load-adapted parts with high precision. However, bulk forming of sheet metals requires high forces, and thus tools applied for the operational demand have to withstand very high contact pressures, which lead to high wear and abrasion. The usage of conventional techniques like hardening and coating in order to reinforce the surface resistance are not sufficient enough in this case. In this paper, the tool resistance is improved by applying filigree bionic structures, especially structures adapted from the Scarabaeus beetle to the tool’s surface. The structures are realized by micromilling. Despite the high hardness of the tool material, very precise patterns are machined successfully using commercially available ball-end milling cutters. The nature-adapted surface patterns are combined with techniques like plasma nitriding and PVD coating, leading to a multilayer coating system. The effect of process parameters on the resistance of the tools is analyzed experimentally and compared to a conventional, unstructured, uncoated, only plasma nitrided forming tool. Therefore, the tools are used for an incremental bulk forming process on 2 mm thick metal sheets made of aluminum. The results show that the developed methodology is feasible to reduce the process forces and to improve the durability of the tools.

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Merklein, Marion, Emanuela Affronti, and Jennifer Steiner. "Numerical Investigation of Dry and Lubricated Sheet Metal Forming Processes." Key Engineering Materials 651-653 (July 2015): 1029–35. http://dx.doi.org/10.4028/www.scientific.net/kem.651-653.1029.

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The current global development towards efficient and sustainable usage of resources as well as a stronger environmental awareness motivates lubrication abandonment in metal forming. Dry forming processes accomplish besides a green production technology also a shortage in production steps and time. However, the change of the tribological conditions influences the material flow during the forming operations and has therefore to be taken into account for the design of complex sheet metal forming operations. The aim of this study is a comparison of dry and lubricated processes by numerical as well as experimental investigations. To ensure reliable results a test setup is necessary which provides a discrete control of the process parameters. Furthermore, an analysis of the local material flow by an optical strain measurement system during the whole test procedure should be possible. These requirements are well fulfilled by the so called Nakajima test, which is typically used for the characterisation of the formability of sheet metals. The influence of varying friction coefficients on the material behaviour is discussed based on the numerical model built up in the Finite Element Software LS-Dyna. The numerical results show a good conformity with the experimental outcomes by identifying the strain localisation. Based on the gained knowledge of the investigations an increase of process understanding for dry forming operations will be derived.

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Meier, Horst, V. Smukala, O. Dewald, and Jian Zhang. "Two Point Incremental Forming with Two Moving Forming Tools." Key Engineering Materials 344 (July 2007): 599–605. http://dx.doi.org/10.4028/www.scientific.net/kem.344.599.

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This paper describes a new development of an incremental, robot based sheet metal forming process for the production of sheet metal components for limited-lot productions and prototypes. The kinematic based generation of the shape is implemented by means of two industrial robots, which are interconnected to a cooperating robot system. Compared to other incremental sheet metal forming machines this system offers a high geometrical form flexibility without the need of any workpiece dependent tools. The principle of the procedure is based on flexible shaping by means of a freely programmable path-synchronous movement of two robots. So far, the final shape is produced by the incremental infeed of the forming tool in depth direction and its movement along the contour in lateral direction on each level. The counter tool, with its simple geometry, was used to support the sheet metal on the backside by moving synchronously along the outer contour, constantly on the same level. This corresponds to a fixed backplate used in other incremental sheet metal forming processes. Due to the use of a new robot system with extended control algorithms for cooperating robots, it will be possible to release the counter tool from its constant path on the outer contour and support the forming tool right on the opposite side of the sheet to generate a predefined gap between the two hemispherical tools. This way at each moment a small part of a full die, as it is used in other processes, is simulated without the need of producing a workpiece dependent die. The extended payload of the new robot system gives the opportunity to form steel blanks, for the first time.

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Mori, Kenichiro. "Application of Servo Presses to Sheet Metal Forming." Key Engineering Materials 473 (March 2011): 27–36. http://dx.doi.org/10.4028/www.scientific.net/kem.473.27.

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Mechanical AC servo presses having high flexibility for control of motion have been recently developed. In these presses driven by servo motors, the slide motion is accurately controlled by real-time feedback of ram position measured with sensors like the conventional machine tools, and thus complicated motion is attainable. The application of servo presses to sheet metal forming processes is reviewed in the present paper. The springback in bending was reduced by bottoming and re-striking. In deep drawing, the forming limit of high strength steel sheets was improved by detaching tools from the sheet, and the wrinkling was prevented by applying a stepwise motion. A hot stamping process using rapid resistance heating and a servo press was developed to produce ultra-high strength steel parts.

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Galanulis, Konstantin. "Optical Measuring Technologies in Sheet Metal Processing." Advanced Materials Research 6-8 (May 2005): 19–34. http://dx.doi.org/10.4028/www.scientific.net/amr.6-8.19.

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During recent years, optical measuring technologies in sheet metal forming and tooling have been used more and more in the industry. Main applications are the digitizing of metal sheet parts and tools, forming analysis of metal sheets as well as the determination of material properties. Good interfaces to conventional CAD/CAM and numerical simulation systems made such optical measuring systems a part of complex process chains. These process chains mainly focus on optimizing the development of products and production processes and on improving the product quality. Using optical systems considerably decreases the development time for products and production while improving the quality.

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Stoughton, Thomas B. "Stress-Based Forming Limits in Sheet-Metal Forming." Journal of Engineering Materials and Technology 123, no. 4 (July 24, 2000): 417–22. http://dx.doi.org/10.1115/1.1398083.

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A strain-based forming limit criterion is widely used throughout the sheet-metal forming industry to gauge the stability of the deformed material with respect to the development of a localized neck prior to fracture. This criterion is strictly valid only when the strain path is linear throughout the deformation process. There is significant data that shows a strong and complex dependence of the limit criterion on the strain path. Unfortunately, the strain path is never linear in secondary forming and hydro-forming processes. Furthermore, the path is often found to be nonlinear in localized critical areas in the first draw die. Therefore, the conventional practice of using a path-independent strain-based forming limit criterion often leads to erroneous assessments of forming severity. Recently it has been reported that a stress-based forming limit criterion appears to exhibit no strain-path dependencies. Subsequently, it has been suggested that this effect is not real, but is due to the saturation of the stress-strain relation. This paper will review and compare the strain-based and stress-based forming limit criteria, looking at a number of factors that are involved in the definition of the stress-based forming limit, including the role of the stress-strain relation.

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Tera, Melania, and Cristina Maria Biris. "Comparison between Deep-Drawing and Incremental Forming Processes from an Environmental Point of View." Materials Science Forum 957 (June 2019): 120–29. http://dx.doi.org/10.4028/www.scientific.net/msf.957.120.

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Deep-drawing is an industrial forming process which allows the user to process large batches of sheet metals parts. One of the major drawbacks of this process is the complexity and the high cost of dies. In comparison incremental forming is a flexible process, allowing the user to obtain sheet metal parts without the need of using a die. The present paper aims to present a comparative study of the two forming processes by presenting the main advantages and drawbacks of each one. The comparative study, aimed on the industrial implementation of the incremental forming process requires a comparison of the two processes regarding the environmental impact. Thus, the results of the study will justify the selection of the incremental forming process in the case of small batches sheet metal parts in conditions of minimal impact on the environment.

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Ingarao, Giuseppe, Giuseppina Ambrogio, Rosanna Di Lorenzo, and Fabrizio Micari. "On the Sustainability Evaluation in Sheet Metal Forming Processes." Key Engineering Materials 473 (March 2011): 824–29. http://dx.doi.org/10.4028/www.scientific.net/kem.473.824.

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In sheet metal forming processes there is still a lack of knowledge in the field of environmental sustainability mainly due to the need of a proper modeling of issues and factors to be taken into account. Such topic is, nowadays, a urgent and remarkable issue in manufacturing and the main concerns are related to more efficient use of materials and energy. What is more, the estimation of environmental burdens of forming technologies is very complex to be accomplished since it is essentially process-dependent. This means that when comparing, for instance, a traditional forming process with an innovative one, there are some peculiar aspects to be considered; actually, processes can be rather different each other in terms of tooling, operative parameters and so on. In this paper, a first modeling effort is presented in order to compare, from a sustainability point of view, a classical stamping process with an incremental forming one. In particular, a frustum of pyramid part is considered and a quantitative analysis of the process energy consumption was developed. The paper aims to provide some sustainability guidelines to promote discussion on limitations, advantages, savings, drawbacks offered by different technologies within sheet metal forming field.

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Kim, J. B., and D. Y. Yang. "Prediction of wrinkling initiation in sheet metal forming processes." Engineering Computations 20, no. 1 (February 2003): 6–39. http://dx.doi.org/10.1108/02644400310458810.

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Strano, M. "Reliability Based Economical Optimization of Sheet Metal Forming Processes." International Journal of Material Forming 3, S1 (April 2010): 41–44. http://dx.doi.org/10.1007/s12289-010-0702-7.

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Thiruvarudchelvan, S., and M. J. Tan. "Recent developments in friction-assisted sheet metal forming processes." Journal of Materials Processing Technology 167, no. 2-3 (August 2005): 161–66. http://dx.doi.org/10.1016/j.jmatprotec.2005.05.030.

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Oh, Soo-Ik, Jong-Kil Lee, Jeong-Jin Kang, and Joo-Pyo Hong. "Applications of simulation techniques to sheet metal forming processes." Metals and Materials 4, no. 4 (July 1998): 583–92. http://dx.doi.org/10.1007/bf03026363.

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Ingarao, G., R. Di Lorenzo, and F. Micari. "Sustainability issues in sheet metal forming processes: an overview." Journal of Cleaner Production 19, no. 4 (March 2011): 337–47. http://dx.doi.org/10.1016/j.jclepro.2010.10.005.

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Hsu, Tze-Chi, and Chan-Hung Chu. "A finite-element analysis of sheet metal forming processes." Journal of Materials Processing Technology 54, no. 1-4 (October 1995): 70–75. http://dx.doi.org/10.1016/0924-0136(95)01922-7.

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Groche, Peter, Jens Ringler, and Dragoslav Vucic. "New Forming Processes for Sheet Metal with Large Plastic Deformation." Key Engineering Materials 344 (July 2007): 251–58. http://dx.doi.org/10.4028/www.scientific.net/kem.344.251.

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Due to the high effort involved, bifurcated constructions in mass market products made from sheet metal remained largely unused. Extruded profiles with cross-sections containing bifurcations show the possibility to increase the stiffness and allow modern lightweight design using load optimized structures as well as in box strap, sandwich and stringer constructions or different profiles. The two new forming processes linear flow splitting and linear bend splitting developed at the PtU enable the production of bifurcated profiles in integral style made of sheet metal without joining, lamination of material or heating of the semi-finished product. These forming processes use obtuse angled splitting rolls and supporting rolls to transform the sheet metal at ambient temperature. Whereas the linear flow splitting process increase the surface of the band edge and forms the band into two flanges. At linear bend splitting a bended sheet metal as semi finished product is used. Thereby bifurcations at nearly any place of a sheet metal can be produced. Both processes induce high hydrostatic compressive stresses in the local forming zone during the process which leads to an increased formability of the material and thereby to the realization of large strains. Parts produced are characterized by increased stiffness, high surface hardness and low surface roughness. Experimental investigations have shown an increasing of the band edge surface at maximum splitting depth up to 1800%. By a following forming process new multi-chambered structures and integral stringer construction can be realized with thin walled cross-sections from steel of higher strength.

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Vierzigmann, Ulrich, Johannes Koch, Marion Merklein, and Ulf Engel. "Material Flow in Sheet-Bulk Metal Forming." Key Engineering Materials 504-506 (February 2012): 1035–40. http://dx.doi.org/10.4028/www.scientific.net/kem.504-506.1035.

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Innovative trends like increasing component functionality, the demand for automotive lightweight constructions and the economic issue to optimize existing process chains, require new ways in manufacturing. Today, the traditional sheet metal and bulk metal forming processes are often reaching their limits if closely-tolerated complex functional components with variants have to be produced. A promising approach is the direct forming of high-precision shapes starting from blanks. Thus, classic sheet metal forming operations, such as deep drawing, are combined with bulk metal forming operations like extrusion of complex variants as for example teeth. This combination of sheet and bulk metal forming operations leads to a side by side situation of different tribological conditions according to the locally varying load situations within the same forming process. This new class of forming processes is defined as sheet-bulk metal forming (SBMF). The tribological conditions in sheet-bulk metal forming processes are of major importance for the process realization, its stability and for the quality of the produced part. The objective of this paper is the investigation of material flow in SBMF in general and the attempt to improve the material flow by local adapted tribological conditions. First the material flow was analyzed by FE-simulation of a model geometry that is typical for SBMF. The investigations with FE-simulation have shown, locally adapted tribological conditions are leading to an improvement in material flow and thus to an increased mould filling. As frictional conditions are directly connected to the topography of workpiece and tool, the modification of the workpiece topography is leading to an alteration in friction values. For the modification of workpiece topography grit blasting was used. The increase in friction of grit blasted surface towards untreated surface was investigates by using the laboratory friction tests. To manufacture specimens with locally adapted topographies for forming tests a masking technique has been developed. The masks are designed after the preliminary findings determined by FE-simulation.

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Sieczkarek, Peter, Lukas Kwiatkowski, A. Erman Tekkaya, Eugen Krebs, Petra Kersting, W. Tillmann, and Jan Herper. "Innovative Tools to Improve Incremental Bulk Forming Processes." Key Engineering Materials 554-557 (June 2013): 1490–97. http://dx.doi.org/10.4028/www.scientific.net/kem.554-557.1490.

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Sheet-bulk metal forming is an innovative process with a high potential to generate load-adapted parts with high precision. Bulk forming processes of sheet metals especially require high process forces, resulting in an intense contact pressure and, thus, in a very high abrasive and adhesive wear. As a method to reduce or avoid these common wear phenomena, even hardened or coated tool surfaces are not sufficient. The objective of this paper is to show an improvement of the tool resistance during an incremental forming process by an adapted tool design and the application of structured tool surfaces combined with coatings. For the tool surface the structure of the scarabaeus beetle serves as the basis for a bionic structure. This structure was manufactured by micromilling. Despite the high hardness of the tool material and the complex geometry of the forming tools, very precise patterns were machined successfully using ball-end milling cutters. The combination of bionic structures with coating techniques like physical vapor deposition (PVD) on plasma nitrided tool surfaces is very promising. In this work, the influence of process parameters (workpiece material, lubrication, tool design, stepwise infeed) on the tool resistance during the forming operation was analyzed experimentally. The results of the optimized forming tools were compared to conventional, unstructured, uncoated, and only plasma nitrided forming tools. The different tools were applied to 2 mm thick metal sheets made of aluminum (AlMg3) and steel (non-alloy quality steel DC04). As a result, the process forces could be reduced by a modified shape and surface of the tools. Thus, the lifetime of the tools can be enhanced.

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Merklein, Marion, Maria Löffler, Daniel Gröbel, and Johannes Henneberg. "Material flow control in sheet-bulk metal forming processes using blasted tool surfaces." MATEC Web of Conferences 190 (2018): 13003. http://dx.doi.org/10.1051/matecconf/201819013003.

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Highly-integrated and closely-tolerated functional components can be produced by sheet-bulk metal forming which is the application of bulk forming operations on sheet metals. These processes are characterized by a successive and/or simultaneous occurrence of different load conditions such as stress and strain states which reduce the geometrical accuracy of the functional elements. Thus, one main challenge within sheet-bulk metal forming is the identification of methods to control the material flow and thus to improve the product quality. One suitable approach is to control the material flow by local modifications of the tribological conditions. Within this study requirements regarding the needed adaption of the tribological conditions for a specific sheet-bulk metal forming process were defined by numerical investigations. The results reveal that a local increase of the friction leads to an improved die filling of the functional elements. Based on these results abrasive blasting as a method to modify the tool surface and thus influencing the tribological behaviour was investigated. For the determination of the tribological mechanism of blasted tool surfaces, the influence of different blasting media as well as blasting pressures on the surface integrity and the friction were determined. The correlations between surface properties and friction conditions were used to derive the mechanisms of blasted tool surfaces.

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Tandon, Puneet, and Om Namah Sharma. "Experimental investigation into a new hybrid-forming process: Incremental stretch drawing." Proceedings of the Institution of Mechanical Engineers, Part B: Journal of Engineering Manufacture 232, no. 3 (May 10, 2016): 475–86. http://dx.doi.org/10.1177/0954405416645983.

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Incremental sheet metal forming is an evolving process, which is suitable for the production of limited quantities of sheet metal components. The main advantages of this process over conventional forming processes are reduced setup cost and manufacturing lead time, as it eliminates the need of special purpose dies, improves formability, reduces forming forces, and provides process flexibility. The objective of this work is to investigate a new hybrid-forming process, which intends to combine incremental sheet metal forming with deep drawing process and has been named as “incremental stretch drawing.” A number of setups and fixtures were developed to carry out experiments to achieve incremental stretch drawing and understand the mechanism of the process. This process addresses some of the challenges of incremental sheet metal forming, that is, limited formability in terms of forming depth, especially at steeper wall angles and subsequent thinning of sheet. It is observed that the proposed process is able to reduce thinning as much as about 300%, considering same forming depth for incremental sheet metal forming and incremental stretch drawing processes. Improvement in formability, in terms of forming depths, also has been observed to be near about 100% in particular cases.

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Weinrich, Andres, Nooman Ben Khalifa, Sami Chatti, Uwe Dirksen, and A. Erman Tekkaya. "Springback Compensation by Superposition of Stress in Air Bending." Key Engineering Materials 410-411 (March 2009): 621–28. http://dx.doi.org/10.4028/www.scientific.net/kem.410-411.621.

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In the sheet metal processing industry bending is one of the common metal forming processes. Depending on the process state, a differentiation has to be made between free bending (air bending) in the die and coining (die bending). Because of its flexibility the air bending process is nowadays one of the widely applied processes for sheet metal bending, but the springback phenomenon is still a great challenge for the industrial application. At the Institute of Forming Technology and Lightweight Construction (IUL) of the Technische Universität Dortmund, Germany, a new method has been developed allowing the compensation of springback effects in air bending of sheet metals. This method is based on the incremental and local superposition of stresses in the forming zone. The superposition occurs after the bending operation but before unloading along the sheet metal width. The advantage of this new method is that a minimal force is required to compensate the springback. This paper describes the springback compensation method in detail and presents first experimental results.

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Zhou, Liu Ru. "Study of Sphere NC Sheet Metal Incremental Forming." Advanced Materials Research 239-242 (May 2011): 1036–39. http://dx.doi.org/10.4028/www.scientific.net/amr.239-242.1036.

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The principle of NC incremental sheet metal forming as well as the process planning, experiment of sphere forming are presented. Because the deformation of sheet metal only occurs around the tool head and the deformed region is subjected to shear deformation and thins, and surface area increases. Sheet metal forming stepwise is to lead to the whole sheet metal deformation. According to sine law, a sphere can’t be formed by NC incremental sheet metal forming process in a single process, rather, it must be formed in multi processes. Thus, the two time path process method is presented to form the sphere, and the experiment is made to verify it. A sphere can be formed from a sheet metal in NC incremental forming process by choosing appropriate tool-path planning. The fracture in the forming component can be avoided by these methods. A sphere of uniform wall-thickness can be formed from the truncated cone by NC incremental forming process.

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Pilz, F., and M. Merklein. "Influence of component design on extrusion processes in sheet-bulk metal forming." International Journal of Material Forming 13, no. 6 (November 13, 2019): 981–92. http://dx.doi.org/10.1007/s12289-019-01522-2.

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Abstract Nowadays, the functional integration of workpieces challenges existing forming processes. The combination of established forming processes – like sheet metal and bulk forming – offers the possibility to counter this issue. The application of bulk forming operations on sheet metal semi-finished products, also called sheet-bulk metal forming (SBMF), is an innovative approach. The potential of SBMF cannot be fully exploited, as there are no recommendations in terms of workpiece design and layout influence on the process result. Therefore, this paper focuses on the analysis of semi-finished products and component design parameters on resulting part and process properties in two extrusion processes in SBMF. The investigation is based on a combined numerical and experimental approach. It is shown that the investigated design parameters, in addition to the achievable dimensional accuracy, substantially influence the occurring tool loads as well as the required process forces.

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Jamshidi, Babak, Farhad Haji Aboutalebi, Mahmoud Farzin, and Mohammad Reza Forouzan. "Numerical Prediction of Damage Evolution in Sheet Metal Forming Processes with Nonlinear and Complex Strain Paths." Key Engineering Materials 473 (March 2011): 653–58. http://dx.doi.org/10.4028/www.scientific.net/kem.473.653.

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Various thin-walled parts with fairly complex shapes are produced from sheet metals such as automotive panels and other structural parts. In these processes, damage and fracture may be observed on the work piece, and formability plays a fundamental role. Therefore, determination of forming limits and prediction of rupture modes in these operations is very important for process design engineers. In this paper, first, based on plane stress elasto-plasticity and finite strain theories a fully coupled elastic-plastic-damage model is used to predict damage evolution in one sheet metal forming process with nonlinear and complex strain paths. As the plane stress algorithm is valid for thin sheet metals and finite strain theory is recommended for large deformations or rotations, the model is able to quickly predict both deformation and damage behaviour of the parts with nonlinear and complex strain paths. The numerical simulations are compared with experimental tests. Comparison of the numerical and experimental results shows that the proposed damage model is accurate for various forming conditions. Hence, it is concluded that finite element method combined with continuum damage mechanics, can be used as a reliable and rapid tool to predict damage evolution in sheet metal forming processes with nonlinear and complex strain paths.

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Grabner, Florian, Belinda Gruber, Carina Schlögl, and Christian Chimani. "Cryogenic Sheet Metal Forming - An Overview." Materials Science Forum 941 (December 2018): 1397–403. http://dx.doi.org/10.4028/www.scientific.net/msf.941.1397.

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Despite extensive efforts to improve energy efficiency in the automotive sector, the use of light-weight aluminium alloys for car bodies is impeded by formability limitations. Although it is a known phenomenon that Al alloys increase their strength and ductility at very low temperatures, it has not been attempted to exploit this effect to increase their overall formability at an industrial scale. Over the last four years, the cryogenic sheet metal forming behaviour of Al-alloys was extensively investigated to establish a process robust enough for manufacturing automotive parts at an industrial level. Initial experiments include tensile tests at temperatures down to –196 °C for characterisation of 5xxx and 6xxx series Al alloys, providing the mechanical material data for numerical design simulations of sheet metal forming processes at cryogenic temperatures. Numerical simulations will not be discussed in this publication. Furthermore, the necessary hardware for cryogenic sheet metal forming was developed and finally resulted in a semi-automated small scale industrial production site. The production of a miniaturized B-Pillar was demonstrated for 5xxx and 6xxx alloys. Due to the part’s demanding geometry, defect-free deep drawing process is possible at cryogenic temperature only. These results demonstrate that the use of Al alloys could be extended beyond their current applications in cars components. For example, the overall formability of 5xxx series alloys nearly doubles compared to room temperature. This paper shall give an overview over our work in the field of cryogenic aluminium sheet metal forming within the last couple of years.

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Chen, Wei, Ming Yan Wu, Zhong Fu Huang, Yi Ding, and Feng Ze Dai. "Studies on the Processes Design of Multi-Step Sheet Metal Forming." Advanced Materials Research 146-147 (October 2010): 1855–58. http://dx.doi.org/10.4028/www.scientific.net/amr.146-147.1855.

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It is well known that the design of multi-step sheet metal forming process is rather difficult. Even small errors may cause significant quality problem. In recent years, finite element analysis (FEA) has being considered as an essential tool for the design. Using a commercial FEA package, DYNAFORM, this paper studies the design of multi-step sheet metal forming processes, especially on how the design of the intermediate steps affect the forming quality. For a rectangle box with a rectangle protrusion inside, several different forming schemes are investigated by means of FEA. The study reveals that the strain path plays an important role. Accordingly, a couple of design rules are suggested.

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Journal articles on the topic 'Sheet metal forming processes'

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