DEVELOPMENT OF THE AUTOMATED SYSTEM AND CONDUCTING EXPERIMENTAL INVESTIGATIONS OF THE FLATNESS OF SHEET METAL WITH THE USE OF THE DIFFRACTION RATTERN AT THE CALIBRATION TABLES

2018 ◽  
Vol 2018 (11) ◽  
pp. 25-30
Author(s):  
V.V. Mozharov ◽  
◽  
C.A. Harahnin ◽  
Keyword(s):  
Sheet Metal ◽  
Automated System ◽  
Experimental Investigations

Numerical Investigation of Dry and Lubricated Sheet Metal Forming Processes

2015 ◽  
Vol 651-653 ◽  
pp. 1029-1035 ◽  
Author(s):  
Marion Merklein ◽  
Emanuela Affronti ◽  
Jennifer Steiner
Keyword(s):  
Sheet Metal ◽  
Sheet Metal Forming ◽  
Metal Forming ◽  
Material Flow ◽  
Test Procedure ◽  
Discrete Control ◽  
Experimental Investigations ◽  
Finite Element Software ◽  
Dry Forming ◽  
Sustainable Usage

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.

Manufacturing Processes for Combined Forming of Multi-Material Structures Consisting of Sheet Metal and Local CFRP Reinforcements

2012 ◽  
Vol 504-506 ◽  
pp. 295-300 ◽  
Author(s):  
Hans Christian Schmidt ◽  
Ulf Damerow ◽  
Christian Lauter ◽  
Bernhard Gorny ◽  
Frederik Hankeln ◽  
...  
Keyword(s):  
Carbon Fibre ◽  
Production Process ◽  
Sheet Metal ◽  
Process Design ◽  
Research Work ◽  
Steel Structures ◽  
Experimental Investigations ◽  
Manufacturing Processes ◽  
Efficient Production ◽  
Material Behaviour

A new and promising approach to the reduction of greenhouse gas emissions is the use of improved lightweight constructions based on multi-material systems comprising sheet metal with local carbon fibre reinforced plastic (CFRP) reinforcements. The CFRP is used to reinforce highly stressed areas and can be aligned to specific load cases. The locally restricted application of CFRP means that the material costs can be effectively reduced by comparison to parts made entirely of CFRP on account of the expensive production process requiring the use of an autoclave. These parts are thus only used in high-priced products. The production of hybrid CFRP steel structures in a mass production process calls for an efficient production technology. Current research work within the scope of a collaborative research project running at the University of Paderborn is concentrating on the development of manufacturing processes for the efficient production of automotive structural components made up of sheet metal blanks with local CFRP patches. The project is focusing especially on basic research into the production of industrial components. The aim of the investigation is to create an efficient and controlled process for producing CFRP reinforced steel structures from semi-finished hybrid steel-CFRP material. This includes tool concepts and an appropriate process design to permit short process times. The basis of an efficient process design is an in-depth knowledge of the material behaviour, and hence a thorough characterisation was performed. Material parameters were determined for both simulation and forming. For this, monotonic tensile, shear and bending tests were conducted using both uncured prepregs and cured CFRP specimens. To achieve an accurate simulation of the forming process, a special material model for carbon fibre prepregs has been developed which also includes the anisotropic material behaviour resulting from fibre orientation, the viscoelastic behaviour caused by the matrix and the hardening effects that prevail during curing. Recent results show good qualitative agreement and will be presented in this paper. In order to control the properties of the hybrid components, four different tool concepts for the prepreg press technology have been developed and tested. The concepts are presented and the results of experimental investigations are discussed in this paper.

Experimental Investigations and Numerical Analysis for Improving Knowledge of Incremental Sheet Forming Process for Sheet Metal Parts

2009 ◽  
Vol 623 ◽  
pp. 37-48 ◽  
Author(s):  
Steeve Dejardin ◽  
Jean Claude Gelin ◽  
Sebastien Thibaud
Keyword(s):  
Sheet Metal ◽  
Incremental Forming ◽  
Single Point ◽  
Sheet Forming ◽  
Incremental Sheet Forming ◽  
Experimental Investigations ◽  
Metal Parts ◽  
Sheet Metal Parts ◽  
Forming Strategy ◽  
Set Up

The paper is related to the analysis of shape distortions and springback effects arising in Single Point Incremental Forming. An experimental set up has been designed and manufactured to carry single point incremental forming on small size sheet metal parts. The experimental set up is mounted on 3-axes CNC milling machine tool and the forming tool is attached and move with the spindle. Experiments have been carried out on sheet metal parts to obtain tronconical shapes. The forming strategy associated to the movement of the forming tool has been also investigated. The experiments indicate that shape distortions arising in the corners of the tronconical shape are clearly related to forming strategy. The springback of rings cut in the tronconical parts have been also investigated. It is shown that positive or negative springback could be also related to forming strategy. In order to enhance experimental investigations, Finite Element simulations of the incremental sheet forming have been performed. Results obtained from the simulations prove that if boundary conditions and forming strategy carefully are taking into account, the finite elements results are in good agreement with experiments. So it is then possible to use FEM as a design tool for incremental sheet forming.

Improvement of Sheet Metal Properties by Inducing Residual Stresses into Sheet Metal Components by Embossing and Reforming

2021 ◽  
Author(s):  
Stefan Walzer ◽  
Mathias Liewald ◽  
Nicola Simon ◽  
Jens Gibmeier ◽  
Hannes Erdle ◽  
...  
Keyword(s):  
Residual Stresses ◽  
Sheet Metal ◽  
Local Property ◽  
Experimental Investigations ◽  
Forming Process ◽  
Novel Approach ◽  
Forming Strategy ◽  
Metal Materials ◽  
Metal Properties ◽  
The One

In sheet metal forming, combination of embossing and reforming allows the mechanical properties of sheet metal materials to be specifically improved. Here, local property modification is achieved by the residual stresses induced as a result of the one-sided embossing process followed by a reforming step. The residual stresses induced in this specific way can lead to a significantly increase in the fatigue strength of processed sheet metal components. However, in order to ensure this kind of component optimization in continuous operation, the induced stresses have to be homogeneous. In this respect, the main objective of the study reported about in this paper was to identify a forming strategy, consisting of the process steps embossing and reforming, that generates preferably homogeneous residual stress distributions into sheet metal blanks. For this, numerical and experimental investigations were carried out with samples of the stainless steel (X6Cr17) having a thickness of 1.5 mm. It was found that embossing and reforming, integrated into a conventional forming process, is a novel approach to specifically induce very localized homogeneous compressive residual stresses in sheet metal materials. This eliminates the need for costly post-processing by means of surface treatment.

New Forming Processes for Sheet Metal with Large Plastic Deformation

2007 ◽  
Vol 344 ◽  
pp. 251-258 ◽  
Author(s):  
Peter Groche ◽  
Jens Ringler ◽  
Dragoslav Vucic
Keyword(s):  
Sheet Metal ◽  
Cross Sections ◽  
Lightweight Design ◽  
High Surface ◽  
Surface Hardness ◽  
Band Edge ◽  
Experimental Investigations ◽  
Large Strains ◽  
Linear Flow ◽  
Flow Splitting

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.

Formability of High Strength Sheet Metals with Special Regard to the Effect of the Influential Factors on the Forming Limit Diagrams

2015 ◽  
Vol 812 ◽  
pp. 271-275 ◽  
Author(s):  
Miklós Tisza ◽  
Péter Zoltán Kovács ◽  
Zsolt Lukács ◽  
Antal Kiss ◽  
Gaszton Gál
Keyword(s):  
Sheet Metal ◽  
Sheet Metal Forming ◽  
Metal Forming ◽  
High Strength Steels ◽  
High Strength ◽  
Forming Limit ◽  
Experimental Investigations ◽  
Sheet Metals ◽  
Forming Limit Diagrams ◽  
Research Activities

Car manufacturing is one of the main target fields of sheet metal forming: thus sheet metal forming is exposed to the same challenges as the automotive industry. The continuously increasing demand on lower consumption and lower CO2 emission means the highest challenges on materials developments besides design and construction. As a general requirement, the weight reduction and light weight construction principles should be mentioned together with the increased safety prescriptions which require the application of high strength steels. However, the application of high strength steels often leads to formability problems. Forming Limit Diagrams (FLD) are the most appropriate tools to characterize the formability of sheet metals. Theoretical and experimental investigations of forming limit diagrams are in the forefront of todays’ research activities.

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