Investigations of ductile damage during the process chains of toothed functional components manufactured by sheet-bulk metal forming

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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Predicting the onset of cracks in bulk metal forming by ductile damage criteria

Procedia Engineering ◽

10.1016/j.proeng.2017.10.1106 ◽

2017 ◽

Vol 207 ◽

pp. 2048-2053 ◽

Cited By ~ 3

Author(s):

Peter Christiansen ◽

Chris V. Nielsen ◽

Paulo A.F. Martins ◽

Niels Bay

Keyword(s):

Metal Forming ◽

Ductile Damage ◽

Bulk Metal ◽

Bulk Metal Forming ◽

Damage Criteria

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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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Machines and Tools for Sheet-Bulk Metal Forming

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.473.91 ◽

2011 ◽

Vol 473 ◽

pp. 91-98 ◽

Cited By ~ 6

Author(s):

Marion Merklein ◽

A. Erman Tekkaya ◽

Alexander Brosius ◽

Simon Opel ◽

Lukas Kwiatkowski ◽

...

Keyword(s):

Metal Forming ◽

Incremental Forming ◽

Batch Size ◽

Bulk Metal ◽

Bulk Metal Forming ◽

New Process ◽

Novel Approaches ◽

The Individual ◽

Forming Tools ◽

Functional Components

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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Functional Analysis of Components Manufactured by a Sheet-Bulk Metal Forming Process

Journal of Manufacturing and Materials Processing ◽

10.3390/jmmp5020049 ◽

2021 ◽

Vol 5 (2) ◽

pp. 49

Author(s):

Andreas Hetzel ◽

Robert Schulte ◽

Manfred Vogel ◽

Michael Lechner ◽

Hans-Bernward Besserer ◽

...

Keyword(s):

Bearing Capacity ◽

Metal Forming ◽

Fatigue Behavior ◽

Design Guidelines ◽

Load Bearing Capacity ◽

Bulk Metal ◽

Load Bearing ◽

Geometrical Properties ◽

Bulk Metal Forming ◽

Functional Components

Due to rising demands regarding the functionality and load-bearing capacity of functional components such as synchronizer rings in gear systems, conventional forming operations are reaching their limits with respect to formability and efficiency. One way to meet these challenges is the application of the innovative process class of sheet-bulk metal forming (SBMF). By applying bulk forming operations to sheet metal, the advantages of both process classes can be combined, thus realizing an optimized part weight and an adapted load-bearing capacity. Different approaches to manufacturing relevant part geometries were presented and evaluated regarding the process properties and applicability. In this contribution, a self-learning engineering workbench was used to provide geometry-based data regarding a novel component geometry with circumferential involute gearing manufactured in an SBMF process combination of deep drawing and upsetting. Within the comprehensive investigations, the mechanical and geometrical properties of the part were analyzed. Moreover, the manufactured components were compared regarding the increased fatigue strength in cyclic load tests. With the gained experimental and numerical data, the workbench was used for the first time to generate the desired component as a CAD model, as well as to derive design guidelines referring to the investigated properties and fatigue behavior.

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Analysis of Effectiveness of Locally Adapted Tribological Conditions for Improving Product Quality in Sheet-Bulk Metal Forming

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.794.81 ◽

2015 ◽

Vol 794 ◽

pp. 81-88 ◽

Cited By ~ 10

Author(s):

Maria Löffler ◽

Daniel Groebel ◽

Ulf Engel ◽

Kolja Andreas ◽

Marion Merklein

Keyword(s):

Metal Forming ◽

Material Flow ◽

Operating Time ◽

Wear Behaviour ◽

Bulk Metal ◽

Bulk Metal Forming ◽

Geometrical Features ◽

Tailored Surfaces ◽

Economic Developments ◽

Functional Components

Due to current ecological and economic developments there is a growing demand for functional components with complex and closely tolerated geometrical features. Conventional sheet and bulk metal forming operations leads to products which are often limited in their geometrical and functional variety. A promising approach is the process-class sheet-bulk metal forming (SBMF). SBMF is characterised by the application of bulk and sheet forming operations on sheet metals [1]. This combination leads to locally and temporally varying load conditions regarding stress as well as strain states. In order to get high quality parts, controlling the material flow is of major importance. Modified Surfaces, so-called tailored surfaces represent an innovative approach to control the material flow. The objective of the current study is the experimental investigation of the effectiveness of locally adapted tribological conditions using workpiece-and tool-sided tailored surfaces within SBMF processes. The study has shown that the local adaption of workpiece and tool surface increased the heights of functional elements. Thus, using locally adapted tribological conditions leads to an improvement of the quality of the produced gearing components. In a further step the influence of surface modifications on the surface properties of the manufactured components are analysed. Additionally, investigations regarding the wear behaviour of tool-sided surface adaptions lead to the assumption, that the effectiveness of tailored surfaces is reduced during the operating time of the tools.

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Plastic flow and its control in sheet–bulk metal forming of thin-walled functional components

CIRP Annals ◽

10.1016/j.cirp.2015.04.078 ◽

2015 ◽

Vol 64 (1) ◽

pp. 245-248 ◽

Cited By ~ 8

Author(s):

Marion Merklein ◽

Maria Löffler ◽

Thomas Schneider

Keyword(s):

Plastic Flow ◽

Metal Forming ◽

Bulk Metal ◽

Bulk Metal Forming ◽

Thin Walled ◽

Functional Components

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Sheet-Bulk Metal Forming of Preformed Sheet Metal Parts

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.473.83 ◽

2011 ◽

Vol 473 ◽

pp. 83-90 ◽

Cited By ~ 8

Author(s):

Thomas Schneider ◽

Marion Merklein

Keyword(s):

Sheet Metal ◽

Deep Drawing ◽

Metal Forming ◽

Sheet Plane ◽

Bulk Metal ◽

Bulk Metal Forming ◽

Sheet Metal Parts ◽

Bulk Forming ◽

Process Factors ◽

Functional Components

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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