Investigation on tailored blanks in a full forward extrusion process of sheet-bulk metal forming

Mapping Intimacies ◽

10.25518/esaform21.3673 ◽

2021 ◽

Author(s):

Manuel Reck ◽

Marion Merklein

Keyword(s):

Heat Treatment ◽

Metal Forming ◽

Material Flow ◽

Sheet Thickness ◽

Extrusion Process ◽

Functional Elements ◽

Bulk Metal ◽

Bulk Metal Forming ◽

Forward Extrusion ◽

Tailored Blanks

Due to the ongoing technological development, the demand for geometrically complicated high performance parts with great functional density is increasing. Often, the use of sheet metal is a beneficial approach in manufacturing technology to meet the requirements on components regarding material strength and lightweight construction goals. The forming of therefore required complex sheet metal part geometries with integrated functional elements cause the need for a three dimensional material flow. Sheet-bulk metal forming, characterized by the application of bulk forming operations on sheet metals, is a suitable approach to produce such components. A challenge is the material flow control, resulting in an insufficient die filling of the functional elements. The use of tailored blanks with a defined sheet thickness distribution is an auspicious approach to face this challenge in subsequent forming processes. In the presented work, semi-finished products with a continuous thickness profile manufactured by orbital forming are applied in a full forward extrusion process. By an additional implementation of a heat treatment, the tailored blanks undergo a recrystallization process that causes a softening of the strain hardened material. In this paper, the potential of a heat treatment in the process class of sheet-bulk metal forming is shown by characterizing the geometrical and mechanical properties of the functional components by applying the mild deep drawing steel DC04 with an initial sheet thickness of t0 = 2.0 mm.

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Material flow control in sheet-bulk metal forming processes using blasted tool surfaces

MATEC Web of Conferences ◽

10.1051/matecconf/201819013003 ◽

2018 ◽

Vol 190 ◽

pp. 13003 ◽

Cited By ~ 1

Author(s):

Marion Merklein ◽

Maria Löffler ◽

Daniel Gröbel ◽

Johannes Henneberg

Keyword(s):

Metal Forming ◽

Material Flow ◽

Simultaneous Occurrence ◽

Tribological Behaviour ◽

Forming Process ◽

Functional Elements ◽

Bulk Metal ◽

Bulk Metal Forming ◽

Main Challenge ◽

Functional Components

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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Improved Sheet Bulk Metal Forming Processes by Local Adjustment of Tribological Properties

Journal of Manufacturing Science and Engineering ◽

10.1115/1.4005313 ◽

2011 ◽

Vol 133 (6) ◽

Cited By ~ 21

Author(s):

H. Hetzner ◽

J. Koch ◽

S. Tremmel ◽

S. Wartzack ◽

M. Merklein

Keyword(s):

Contact Pressure ◽

Metal Forming ◽

Material Flow ◽

System Analysis ◽

Sheet Thickness ◽

Fe Model ◽

Forming Process ◽

Bulk Metal ◽

Bulk Metal Forming ◽

Functional Features

This paper is focused on a combined deep drawing and extrusion process dedicated to the new process class of sheet bulk metal forming (SBMF). Exemplified by the forming of gearings, combined sheet and bulk forming operations are applied to sheet metal in order to form local functional features through an intended and controlled change of the sheet thickness. For investigations on the form filling and the identification of significant influencing factors on the material flow, a FE simulation model has been built. The FE model is validated by the results of manufacturing experiments using DC04 with a thickness of 2.0 mm as blank material. Due to the fact that the workpiece is in extensive contact to the tool surface and that the pressure reaches locally up to 2500 MPa, the tribological conditions are a determining factor of the process. Thus, their influence is discussed in detail in this paper. In the first instance, different frictional zones having a distinct effect on the resulting material flow are identified and their effect on improved form filling is demonstrated. Subsequently, a more comprehensive methodology is developed to define tribological zones of forming tools. For this, a system analysis of the digital mock-up of the forming process is performed. Besides friction, other relevant aspects of forming tool tribology like contact pressure, sliding velocity, and surface magnification are considered. The gathered information is employed to partition the tools into tribological zones. This is done by systematically intersecting and re-merging zones identified for each of the criterion. The so-called load-scanning test allows the investigation of the friction coefficient in dependence of the contact pressure and possible loading limits of tribological pairings. It provides an appropriate tribological model test to evaluate tribological measures like coatings, surface textures and lubricants with respect to their targeted application in particular zones. The obtained results can be employed in the layout of further forming processes to reach the desired process behavior. This can be, for example, an improved form filling, less abrasive wear and adhesive damage or lower forming forces, respectively tool load for an improved durability of the die.

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Extension of the forming limits of extrusion processes in sheet-bulk metal forming for production of minute functional elements

Manufacturing Review ◽

10.1051/mfreview/2020003 ◽

2020 ◽

Vol 7 ◽

pp. 9 ◽

Cited By ~ 2

Author(s):

Florian Pilz ◽

Johannes Henneberg ◽

Marion Merklein

Keyword(s):

Sheet Metal ◽

Metal Forming ◽

Extrusion Process ◽

Process Conditions ◽

Functional Elements ◽

Bulk Metal ◽

Bulk Metal Forming ◽

Lateral Extrusion ◽

Component Design ◽

Tailored Surfaces

Increasing demands in modern production pose new challenges to established forming processes. One approach to meet these challenges is the combined use of established process classes such as sheet and bulk forming. This innovative process class, also called sheet-bulk metal forming (SBMF), facilitates the forming of minute functional elements such as lock toothing and gear toothing on sheet-metal bodies. High tool loads and a complex material flow that is hard to control are characteristic of SBMF. Due to these challenging process conditions, the forming of functional elements is often insufficient and necessitates rework. This negatively affects economic efficiency. In order to make use of SBMF in industrial contexts, it is necessary to develop measures for improving the forming of functional elements and thereby push existing forming boundaries. This paper describes the design and numerical replication of both a forward and a lateral extrusion process so as to create involute gearing in combination with carrier teeth. In a combined numerical-experimental approach, measures for extending the die filling in sheet-metal extrusion processes are identified and investigated. Here, the focus is on approaches such as process parameters, component design and locally adjusted tribological conditions; so-called ‘tailored surfaces’. Based on the findings, fundamental mechanisms of action are identified, and measures are assessed with regard to their potential for application. The examined approaches show their potential for improving the forming of functional elements and, consequently, the improvement of geometrical accuracies in functional areas of the workpieces.

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Sheet-Bulk Metal Forming of Symmetric and Asymmetric Parts

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.769.229 ◽

2013 ◽

Vol 769 ◽

pp. 229-236 ◽

Cited By ~ 7

Author(s):

Valerian Salfeld ◽

Richard Krimm ◽

Sven Hübner ◽

Thorsten Matthias ◽

Milan Vucetic

Keyword(s):

Metal Forming ◽

Material Flow ◽

Three Dimensional ◽

Positive Influence ◽

Sheet Metals ◽

Functional Elements ◽

Bulk Metal ◽

Bulk Metal Forming ◽

New Machine

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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Test of Friction Parameters in Bulk Metal Forming Based on Forward Extrusion Processes

Journal of Shanghai Jiaotong University (Science) ◽

10.1007/s12204-020-2162-7 ◽

2020 ◽

Vol 25 (3) ◽

pp. 333-339

Author(s):

Xia Chen ◽

Tong Wen ◽

Kefan Liu ◽

Yifei Hong

Keyword(s):

Metal Forming ◽

Bulk Metal ◽

Bulk Metal Forming ◽

Forward Extrusion ◽

Friction Parameters

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Fundamental investigations on the material flow at combined sheet and bulk metal forming processes

CIRP Annals ◽

10.1016/j.cirp.2011.03.146 ◽

2011 ◽

Vol 60 (1) ◽

pp. 283-286 ◽

Cited By ~ 52

Author(s):

M. Merklein ◽

J. Koch ◽

S. Opel ◽

T. Schneider

Keyword(s):

Metal Forming ◽

Material Flow ◽

Bulk Metal ◽

Bulk Metal Forming

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Investigation on blasted tool surfaces as a measure for material flow control in sheet-bulk metal forming

Manufacturing Review ◽

10.1051/mfreview/2019012 ◽

2019 ◽

Vol 6 ◽

pp. 10 ◽

Cited By ~ 3

Author(s):

Marion Merklein ◽

Maria Löffler ◽

Daniel Gröbel ◽

Johannes Henneberg

Keyword(s):

Metal Forming ◽

Material Flow ◽

Simultaneous Occurrence ◽

Tribological Behaviour ◽

Bulk Metal ◽

Geometrical Accuracy ◽

Bulk Metal Forming ◽

Tribological System ◽

Local Modification ◽

Functional Components

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 metal. These processes are characterized by a successive and/or simultaneous occurrence of different load conditions which reduce the geometrical accuracy of the parts. One challenge within sheet-bulk metal forming is the identification of methods to control the material flow to improve the product quality. A suitable approach is the local modification of the tribological conditions. Within this study, requirements regarding the needed adaption of the tribological system for a specific process were defined by numerical investigations. The results reveal that a local increase of the friction leads to an improved geometrical accuracy. 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. Additionally, the functional stability of a modification was investigated. Finally, the correlations between surface properties and friction conditions were used to derive the mechanisms of blasted tool surfaces.

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