Marion Merklein

• Friedrich-Alexander-University Erlangen-Nürnberg

Because of growing environmental and technical requirements, the efficient manufacturing of components with tailored properties using recyclable materials is mandatory. The combination of high-strength aluminum alloys and thermal-assisted forming operations is an innovative method for the production of components with varying mechanical properties....

The mass production of bipolar plates for electrolyzers and fuel cells is a central step towards the realization of efficient and cost-effective energy systems of the future. However, current production processes are reaching their limits and can hardly realize the quantities that will soon be demanded, nor can they scale up to the required volumes...

Precise material characterization is a key factor not only for representative finite-element-analysis (FEA) in production technology, but also for product development in general. Hereby, the tensile test is of particular importance, as it can be used to determine the most relevant material parameters. These are used to ensure a better process and t...

High-strength aluminum alloys are more and more used for safety and crash-relevant components due to their advantageous density-to-strength ratio. By using thermal-supported forming strategies, failure-free deep drawing is possible for these materials. In this context, the hot form quench process (HFQ ® ) has shown to be a promising thermally-assis...

In the automotive sector, an important strategy for reducing CO2-emissions is lightweight construction. In this regard, body-in-white parts offer a high potential for weight reductions by substituting conventional steel parts with tubular, aluminum-based components. Due to their high strength-to-weight-ratio and high crashworthiness, tube profiles...

In many industries, there is a trend towards miniaturization of technical components, such as drive systems, which enable the solution of high-precision positioning tasks because of their low volume and high dynamics. Geared micro parts are currently mainly produced by cutting and LIGA processes, but in mass production cold forming offers ecologica...

The increasing miniaturization of technical systems leads to a rising demand for micro components. Miniaturized drive systems with geared micro parts or micro gears are applied in various industries. Due to the demand for high production volumes, productive and resource-efficient fabrication is of major importance. Compared to industrially applied...

The progressively more demanding needs of emissions and costs reduction in the transportation industry are pushing engineers towards the use of increasingly lightweight structures. This goal can be achieved only if dissimilar and/or new materials, including polymers and composites, are joined together to create complex structures. Conventional fusi...

Digitalization in the metal forming industry needs to be improved to achieve the goals set by Industrie 4.0. Distributed-Ledger-Technology (DLT) has been identified as a promising foundation for tackling the underlying problem of consistent information exchange. DLT-based solutions have already been developed, but none explicitly covers the roll fo...

Mechanical joining technologies are increasingly used in multi-material lightweight constructions and offer opportunities to create versatile joining processes due to their low heat input, robustness to metallurgical incompatibilities and various process variants. They can be categorised into technologies which require an auxiliary joining element,...

The process chain for the manufacturing of sheet metal components in mass production includes various cutting and forming operations, which influence the resulting properties of the parts and therefore subsequent manufacturing steps, such as clamping and joining. It is shown that clamping of the components leads to superimposed residual stresses an...

Mechanical joining technologies like self-piercing riveting are gaining importance with regard to environmental protection, as they enable multi-material design and lightweight construction. A new approach is the use of high nitrogen steel as rivet material, which allows to omit the usually necessary heat treatment and coating and thus leads to a s...

Shear-clinching has proven to be a suitable technology for joining of high-strength materials. However, the mechanical properties of the upper joining partner are limited due to the high strains, which occur during the process. Therefore, shear-clinching of the high-strength aluminum alloy AA7075 in the T6 temper is not possible. Yet, the mechanica...

Fluctuations of material properties are one reason for the occurrence of cracks and waviness in series production of car body parts. Especially fluctuating tribological conditions have an effect on the friction behavior and thus on the material flow. So far fluctuating material properties are not considered in the standard FE-simulation and consequ...

In this review the authors provide a comprehensive insight into additive manufacturing process mechanics which explore how thermodynamics give rise to characteristic microstructure and property. Discussion is then given over to how solidification microstructure is modified using processing conditions and utilisation of traditional casting methods w...

The material pairing metal-plastic offers advantages such as a reduced weight and the ability to be operated in dry conditions, but the application is limited due to the occurring wear. The properties of the metallic gearing have a significant influence on the wear behavior. From previous investigations on the application of steel within the materi...

In the last few decades, metal-based composites and related manufacturing methods have attained a significant research attention thanks to the possibilities they offer to tailor both the material properties and the part in-service performances. A variety of metal-based composite parts is available for commercial applications since more affordable a...

The use of conventional resistance spot welding in the car body shop for joining an aluminium part to a steel part is possible with the process-invention of the resistance element welding (REW) with upset auxiliary joining elements. Within this process, the challenges arise from the novel approach of combining forming process steps in the insertion...

High-strength aluminum alloys of the 7XXX series have a high potential for safety and crash-relevant components due to their advantageous density-to-strength ratio. Currently, the use of these alloys is limited because of the low formability at room temperature. By using thermal supported forming strategies, failure-free deep drawing is possible fo...

Concerning lightweight design, hot stamping of boron-manganese steels has developed to a state-of-the-art process for manufacturing safety-relevant car body parts in the last two decades. To further improve passenger safety, the idea of components with tailored properties has become even more important. Normally, these process variants aim to bring...

Hot stamping of boron manganese steel is a state of the art process for manufacturing safety-relevant automotive components with regard to lightweight design. In terms of the mechanical properties, the microstructural evolution is of particular interest. Besides conventional hot stamping processes, this is especially apparent for the manufacture of...

The combination of additive manufacturing (AM) and forming offers new opportunities in part and process chain design. To show the potential of this process combination, a gear component with discrete tooth geometry is manufactured by powder bed fusion of metal using a laser beam (PBF-LB/M) and forming. Such gear components are manufactured conventi...

Functional integration and lightweight construction pose increasing demands on manufacturing processes and require innovative approaches. In this context, sheet-bulk metal forming combines the advantages of conventional sheet and bulk forming processes expanding the limitations of these particular processes. However, the intended three-dimensional...

Deviations of the properties of semi-finished sheet metal parts affect the finished part’s geometry and its properties. With knowledge of the deviations, forming processes can be adjusted to a certain degree in order to maintain the part quality. Typically, in mass production, the sheets are blanked before deep drawing. Within the blanking processe...

In the drive and transmission technology, gears rank among the most frequently used machine elements in modern automotive and mechanical engineering. Gears are conventionally produced by cutting processes, as high geometrical quality standards are hereby ensured. With regard to economic and ecological aspects, cold forging represents a promising al...

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),...

The approach of 316L hybrid parts consisting of sheet metal with additively manufactured element is investigated regarding relative density, warpage and bonding strength between additively manufactured element and sheet metal. Process parameters for manufacturing hybrid parts with relative density of 99.9 % are identified. Warpage is a critical asp...

The current trend of mass customization pushes conventional production techniques to their limits. In the case of forming technology, limitations in terms of adaptability and flexibility emerge, while additive manufacturing lacks in the manufacturing of large, geometrically simple components. Combining both processes has potential to use the streng...

Today’s manufacturing facilities and processes offer the potential to collect data on an unprecedented scale. However, conventional Programmable Logic Controllers are often proprietary systems with closed-source hardware and software and not designed to also take over the seamless acquisition and processing of enormous amounts of data. Furthermore,...

Sheet-bulk metal forming is an expedient approach to efficiently manufacture functional components out of sheet metal. In order to reduce weight of the component manufactured, an application-adapted approach was developed to replace the conventional steel blank by a semi-finished product consisting of two blanks with half the thickness to enable th...

Due to the trend towards lightweight design in car body development mechanical joining technologies become increasingly important. These techniques allow for the joining of dissimilar materials and thus enable multi-material design, while thermic joining methods reach their limits. Semi-tubular self-piercing riveting is an important mechanical join...

With the demand for more efficient vehicles, lightweight design has become an important manufacturing goal. Because of the high specific strength and the good corrosion resistance, aluminum alloys are widely used. However, the industrial use of high strength aluminum alloys is still limited because of its low formability. With the help of thermal s...

In sheet and bulk forming, numerical simulation has become established over the last 20 years as an indispensable tool for research and industrial practice. The numerical calculation of forming processes supports a time- and cost-efficient development in the context of a virtual product evaluation. Currently, simulation and measurement results are...

An increasingly connected production in the sense of Industry 4.0 allows completely new possibilities in regard to improved and more efficient production and higher product quality. But a key factor to Industry 4.0 is a consistent data flow along the production chain. However, the exchange of data, especially between companies, still is a major obs...

The quality of car body parts in series production is strongly dependent on the tribological behavior. Fluctuating material properties such as the sheet roughness and the amount of lubricant have an influence on the forming process. On the basis of large amounts of data it is possible to investigate the friction behavior in series production and to...

The compliance with increasingly stricter emission standards is a challenge for the automotive industry, which requires the utilization of lightweight materials e. g. aluminium and high‐strength steels. Hereby, the load‐optimized design of body parts and the reduction of wall thicknesses are enabled. But, due to the use of dissimilar materials, com...

The increasing demand for closely tolerated and highly integrated functional components motivates the development of the innovative process class sheet-bulk metal forming (SBMF). SBMF is defined as the application of bulk forming operations on sheet metal to produce parts with integrated functional elements. Due to varying tribological loads, cause...

Increasing demands on forming processes with regard to the functional integration of components and lightweight construction pose a challenge to conventional processes. The application of bulk forming operations on sheet metal semi-finished products, also called sheet-bulk metal forming (SBMF), is a suitable approach to meet these challenges. Insuf...

In recent years there have been increasing attempts to enable the production of net-shape gears by forming methods. Cold forging enables improved material and energy efficiency compared to conventional gear manufacturing processes. In the extrusion process, a high surface quality, an increased hardness of the tooth profile as well as a load adapted...

Sheet-bulk metal forming (SBMF) processes are characterized by a successive and/or simultaneous occurrence of different load conditions such as the stress and strain states. These conditions influence the material flow and often lead to a reduced geometrical accuracy of the produced components. To improve the product quality, a control of the mater...

The tribological behavior in the series production of car body parts plays a key role for part quality. However, there are still unresolved issues concerning the tribological system. Fluctuating material properties as well as further influencing variables have an impact on the friction behavior during the forming process and therefore influence on...

Die Blechmassivumformung erlaubt die effiziente Herstellung von leichtbaugerechten Funktionsbauteilen mit verschiedenartigen Nebenformelementen in einem kombinierten einstufigen Tiefzieh- und Stauchprozess. Durch die Analyse der Umformergebnisse mit konventionellem Halbzeug anhand von Gefügeschliffbildern und Härtemessungen lassen sich Bauteilfehle...

Surface structures are used for several applications in industry to enhance the characteristics of surfaces and therefore processes. One example is the Sheet-bulk metal forming process which combines the advantages of bulk and sheet metal forming. Due to the complex material flow and load, the tool surfaces do need adapted tribological properties....

Economic and ecological demands like saving resources and improved material efficiency can be achieved by the application of process adapted semi-finished parts, so-called tailored blanks, for the manufacturing of for example gearings or synchronizer rings. Functional components require the locally restricted distribution of an adequate amount of m...

To encounter trends regarding an efficient production of complex functional components in forming technology, the process class of sheet-bulk metal forming (SBMF) can be applied. SBMF is characterized by the application of bulk forming operations on sheet metal, often in combination with sheet forming operations [1]. The combination of these conven...

The increasing number of electronics in several industrial sectors leads to a rising demand for flexible and adaptable electronic systems with high functional density and resilience. An efficient method for producing such parts is the encapsulation of metal inserts, for example lead frames, by means of assembly injection molding. Here one major cha...

Current challenges like increasing safety standards and reducing fuel consumption motivate lightweight construction in modern car bodies. Besides using lightweight workpiece materials like aluminum, hot stamping has been established as a key technology for producing safety relevant components. Producing hot stamped parts out of ultra-high strength...

Nowadays lightweight design in metal forming processes leads to complex deep drawing geometries, which can cause multiple damages. Therefore, drawbeads are one way to regulate and control material flow during the forming process. Not only in research, but also in industrial practice, it could be determined that material is work hardened passing dra...

The fourth industrial revolution represents a new stage in the organization and management of the entire value chain. However, concerning the field of forming technology, the fourth industrial revolution has only arrived gradually until now. In order to make a valuable contribution to the digital factory the controlling of a multistage forming proc...

Within the last decades, stringent regulations on fuel consumption, CO2 emissions and product recyclability forced the automotive sector to implement new strategies within the field of car body manufacturing. Due to their low density and good corrosion resistance, aluminum became one of the most relevant lightweight materials. Recently, especially...

The demand for new processes to produce high strength parts, under appropriate cost and productivity, has grown with weight reduction and crash safety improvements in automobile design. The hot stamping processes of quenchable steel sheets potentially offer not only small forming load and high formability, but also high strength and no springback b...

Aufgrund verschiedener Einflussfaktoren steigt das Gewicht der Fahrzeuge in der Automobilindustrie jährlich an. Nicht nur kundenseitige Anforderungen nach mehr Komfort und die damit verbundenen Zusatzausstattungen, sondern auch gesetzliche Regularien in Bezug auf die Sicherheit der Insassen tragen zu dieser Entwicklung bei. Zeitgleich werden neue s...

Hot stamping is a well-established process for the production of structural automotive parts with an excellent strength-to-weight ratio. The complexity of the thermo-mechanical history in hot stamping requires a precise virtual design of hot stamping processes. The thermal and mechanical characteristics of the most common press hardening steel 22Mn...

Forming of parts with thick-walled functional elements out of sheet metal requires innovative manufacturing methods and a fundamental and holistic process understanding. The sheet-bulk metal forming process applied in this investigation is a single-stage combination of deep drawing and upsetting. It enables the manufacturing of cups with circumfere...

Laser Metal Deposition (LMD) with Blown Powder and Laser Beam Melting (LBM) in Powder Bed are two Additive Manufacturing technologies that can produce high-quality metal parts in principle. Both technologies are based on melting of fine metal powders employing high intensity laser radiation. Apart from the obvious differences defined by system tech...

Global trends like growing environmental awareness and demand for resource efficiency motivate an abandonment of lubricants in metal forming. However, dry forming evokes increased friction and wear. Especially, dry deep drawing of aluminum alloys leads to intensive interaction between tool and workpiece due to its high adhesion tendency. One approa...

This study addresses the analysis of edge crack sensitivity of DP800 steel and AA5182 aluminum alloy in dependency of punching and machining operation as well as load case of subsequent forming. The inserting of a round hole by punching with defined punch-to- die-clearance, milling and drilling is compared. Subsequent forming is performed by standa...

The manufacturing process of car body parts needs to be adaptable during production because of fluctuating variables; finding the most suitable settings is often expensive. The cause-effect relation between variables and process results is currently unknown; thus, any measure taken to adjust the process is necessarily subjective and dependent on op...

Concerning a low specific density, magnesium alloys offer a great potential to reduce the part weight. Due to the conditional formability of magnesium alloys at room temperature, forming processes are mostly realized at elevated temperatures. Within this contribution, uniaxial tensile tests for two different specimen geometries with a gauge length...

In order to produce components with massive secondary functional elements from sheet metal bulk forming operations, termed sheet-bulk metal forming, can be applied. Owing to high, three-dimensional stress and strain states present during sheet-bulk metal forming, ductile damage occurs in the form of micro-voids. Depending on the material flow prope...

Neue Prüfstrategien und Modellierungsansätze tragen zum grundlegenden Verständnis und zur exakten Abbildung des Werkstoffverhaltens bei. Sie ermöglichen damit die virtuelle Prozessauslegung, um das Potenzial von Magnesiumlegierungen als Leichtbauwerkstoff der Blechumformung besser einsetzen zu können.

Sheet-bulk metal forming (SBMF) is characterized by successive and/or simultaneous occurrence of quite different load conditions regarding stress and strain states. These conditions significantly influence the material flow and thus the geometrical accuracy of the components. To improve the product quality a control of the material flow is required...

Ultrafine-grained accumulative roll bonded (ARB) sheet metals of aluminum alloys have a high potential for lightweight construction. The mechanical properties can be enhanced regarding strength and ductility by the combination of ARB and a local heat treatment according to the Tailor Heat Treated Blanks technology. The present investigation focuses...

The aim of this work is the improvement of a constitutive friction law which has been identified for the specific demands of sheet-bulk metal-forming. The constitutive friction law determines the friction shear stress in dependency on the plastic smoothing of the surface roughness, which also affects the real contact area. An experimental setup is...

Due to increasing economic and ecological restrictions, conventional sheet and bulk forming operations often reach their limits with regard to part weight and functional integration. One solution to meet those challenges is provided by sheet-bulk metal forming (SBMF) processes. SBMF is defined as the application of bulk forming operations on sheet...

Inverse form finding aims in determining the optimal material configuration of a workpiece for a specific forming process. A gradient- and parameter-free (nodal-based) form finding approach has recently been developed, which can be coupled non-invasively as a black box to arbitrary finite element software. Additionally the algorithm is independent...

Sheet-bulk metal forming as a new class of manufacturing processes is one of the possible answers production processes provide to the increasing demands on functional integration into light weight parts made of high strength steel. Research in this field is carried out in several places. The special issue was initiated by the Transregional Collabor...

To produce parts from sheet metal with thickened functional elements, bulk forming operations can be employed. For this new process class, the term sheet-bulk metal forming has been established recently. Since sheet-bulk metal forming processes such as orbital forming generates triaxial stress and strain states, ductile damage is induced in the for...

Sheet-bulk metal forming processes combine conventional sheet forming processes with bulk forming of sheet semi-finished parts. In these processes the sheets undergo complex forming histories. Due to in- and out-of-plane material flow and large accumulated plastic strains, the conventional failure prediction methods for sheet metal forming such as...

Sheet-Bulk Metal Forming (SBMF) allows the manufacture of complex parts with integrated functional form elements, such as teeth and thickened areas. Therefore, bulk forming operations are applied to sheets with initial thicknesses of 2 or 3 mm. The design and functionality of the tools are as important as the process itself. Therefore, the working...

Using sheet-bulk metal forming processes the application of bulk forming operations on sheet metals enables the manufacturing of functional components with local wall thickness variations. As these processes come along with a two- and three-dimensional material flow, the control of the material flow is crucial for ensuring a proper filling of funct...

Beim Kaltfließpressen besitzt die Oberflächenbeschaffenheit des Werkzeugs einen ausgeprägten Einfluss auf das Werkzeugeinsatzverhalten. Durch die hohen Werkzeugbeanspruchungen ist in vielen Fällen die Standmenge durch Ermüdungsversagen begrenzt. Vor diesem Hintergrund wurde in diesem Fachbeitrag das Potential der Integration einer abrasiven und ver...

Complex parts with sharp corners are on the rise to satisfy increasing customer demands on the design. To realize these parts in single or multistage forming processes the information of the material behavior under linear and non-linear strain paths is essential. As Bauschinger already showed for the material behavior under cyclic loading, a reduct...

Hot stamping is a well-established process in car manufacturing today. However, the resulting mechanical properties of a hot stamped part and its behaviour during a crash are still open questions. The usual procedure includes destructive experiments to determine the mechanical properties resulting from the forming and quenching process. The gained...

The intensifying regulations for CO2 emissions of passenger cars lead to increased efforts in the field of lightweight construction. In this context, the application of aluminium is a promising strategy. Another approach is the implementation of high strength materials to enable the reduction of the wall thickness of components and to ensure the cr...

Environmental awareness and a growing demand for efficient resource utilization encourage the realization of lubricant-free forming processes. A first step in accomplishing dry sheet metal forming is to gain knowledge about the changing tribological conditions and to identify the relevant influencing parameters. The commonly used flat strip drawing...

In many industrials field, especially in the automotive sector, there is a trend toward lightweight constructions in order to reduce the weight and thereby the CO₂ and NO x emissions of the products. An auspicious approach within this context is the substitution of conventional deep drawing steel by precipitation hardenable aluminum alloys. However...

In modern car bodies lightweight structures are used to achieve a reduction of energy consumption and CO2-emissions. One of the most important lightweight materials is aluminum and its alloys. Current state of the art in automotive industry is utilizing precipitation hardenable aluminum alloys of the 6000 series whereas the crash-relevant strength...

The manufacturing of steel gears by cold forging can be realized by using the so called Samanta process. The present study focuses on the one hand on the FE based analysis of the forming of gears in forward extrusion and on the other hand on the modelling of a Samanta process, using the software Simufact.forming. Thereby the influence of different...

The application of bulk forming operations on sheet metal enables the manufacture of functional components with local wall thickness variations. Using process adapted semi-finished parts with a local material pre-distribution and strain hardening in these processes leads to an increased forming of the functional components. In addition material eff...

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-b...

Lightweight design and modern production technologies are key factors for the success of today’s car manufacturing industry. Resulting challenges, like the usage of new materials in the production chain and the joining of dissimilar material combinations for composite constructions, require the constant improvement and innovative development of pro...

The paper gives a review of the main research activities recently carried out in the framework of hot stamping of boron steel sheets with tailored properties. The focus is on the process variants developed to locally adjust the mechanical properties of the hot stamped component as well as on the testing and modeling techniques needed to calibrate t...

The paper gives an overview on the application of sheet-bulk metal forming operations in both scientific and industrial environment. Beginning with the need for an innovative forming technology, the definition of this new process class is introduced. The rising challenges of the application of bulk metal forming operations on sheet metals are prese...

The desire for individualized products forces the companies to a great diversity of combinable parts. This way, the clients can compile their personalized product. As this trend is not just limited on visual parts but also for functional components, laser additive manufacturing of metals is used more and more often in manufacturing. To bring more a...

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...

The quality of additive manufactured parts depends, however, a lot on the workers experience to control porosity, layer linkage and surface roughness. To analyze the robustness of the Laser Beam Melting (LBM) process, a Round Robin test was made in which specimens from four institutes from different countries were tested and compared. For the tests...

Tailor Heat Treated Profiles (THTP) are profiles that exhibit local different mechanical properties optimized for a subsequent forming operation. The property distribution is realized by short term heat treatment before a forming operation. Based on the interaction of soft and hard areas the material flow can be improved and the formability can be...

Metal forming is not only shaping the form of a product, it is also influencing its mechanical and physical properties over its entire volume. Advanced analysis methods recently enable accurate prediction of these properties and allow for setting these properties deterministically during the forming process. Effective measurement methods ensure the...

Tailor heat treated blanks (THTB) are a well-known approach to considerably enhance the forming limits of 6xxx-aluminum alloys. This is realized by locally adjusting the mechanical properties with regard to a forming operation using a short term heat treatment. However, the resulting temperature distribution unavoidably leads to distortion of the b...

The trend toward miniaturization of metallic microparts results in the need of high-precision production methods. Major challenges are, for example, downsizing of tools and adequate positioning accuracy within blanking. Starting from a novel approach for tool miniaturization and its realization, the aim of this study is showing the assessment of to...

Gegenwärtige Entwicklungstrends in der Umformtechnik [1] erfordern eine stetige Verbesserung der Werkzeugqualität, um hohe Werkzeugstandmengen zu gewährleisten. Werden besondere Anforderungen hinsichtlich der Verschleißfestigkeit gestellt oder erfordert ein Umformprozess einen Werkzeugwerkstoff mit erhöhter Druckfestigkeit, kommen oftmals Hartmetal...