The use of advanced high-strength steels (AHSS) is associated with increased springback and represents a great challenge for today's press shops with regard to the dimensional accuracy of cold-formed sheet metal parts. Springback, its appearance and characteristics are mainly dependent on the stress state introduced by the forming process and part geometry before opening the tools. With the aim of determining the influence of the forming process on springback, sheet metal forming simulation is used in this contribution to analyze a hat profile from a high-strength dual-phase steel (DH1000) by three different forming processes: crash forming, bending and drawing. For this purpose, the stresses generated by these processes and resulting springback are examined considering the respective forming history. The results show the strong influence of the material flow controlled by the process and tool geometry on the stress state before springback, which leads to significant differences in the springback of the hat profile among the forming processes: springback increases from crash forming to bending and drawing.

Defined surface micrcotextures offer potential for the friction reduction in elastohydrodynamic contacts and can thus increase the energy efficiency of technical systems. The production of prostheses, where microtextured surfaces can provide anti-bacterial effects is another application area. To manufacture these components economically in large quantities, forming processes are to be aimed at. Since lightweight parts are crucial in most application areas, the forming of sheet metal is the subject of current research. A major aspect of the presented investigation is the behavior of tool materials for the production of such microtextured sheet metal parts. Applying microtextures of varying geometries to the tools is a key challenge. Limitations in the accuracy of electrical discharge machining processes for the fabrication of micro cylinders, prisms and cuboids are therefore analyzed on the high-speed steels 1.3343 and 1.3244. In addition, the tool surfaces are characterized regarding their friction properties with case hardening steel as a contact partner. In this paper, the tool friction is analyzed for the steel 1.7131 (16MnCr5) with an initial sheet thickness of t₀ = 2.4 mm, which is often utilized for high-wear applications due to its high strength and toughness. In this context, the friction behavior of the wax-containing lubricant Beruforge 150 DL made for bulk forming processes is compared with zinc-free high-performance lubricants Raziol CLF 65-400 of varying viscosity.

Mechanical strengthening of sheet material can be realized by accumulative roll bonding, which belongs to the severe plastic deformation processes. Beside fine-grain hardening also work and precipitation hardening is responsible for the rise of material strength. However, this is also accompanied by a significant decrease in ductility. Thus, the need for an enhancement of ductility is essential for a sufficient formability in later applications and was already introduced by tailored heat treatments. The challenge, however, is to realize a process temperature that leads to a degradation of dislocations and dissolution of MgSi-precipitations, without a recrystallization of the fine-grained microstructure to coarse grain sizes. In order to identify a suitable temperature range to avoid recrystallization, hot forming experiments are carried out at successive temperatures from 20 to 300°C. Tensile specimens are drawn with the thermomechanical simulator Gleeble 3500 (Dynamic Systems Inc.) aided by the strain measurement system Aramis (GOM GmbH). The aim is to investigate the dependence of the mechanical properties from the forming temperature in order to identify a temperature range, in which high strength with simultaneous enhanced ductility is maintained.

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 ecological and economic benefits. However, the cold forming of micro gears is restricted to a lower module limit of m = 0.2 mm due to high tool stresses, size effects and handling difficulties. To solve these challenges, in this contribution a three-stage forming process chain for the manufacturing micro gears (m = 0.1 mm) is investigated. In the first stage, a pin as wheel blank is extruded from sheet metal, which is geared subsequently by lateral extrusion. Finally, the micro gear is separated from sheet by shear cutting. The aim of this study is to demonstrate the applicability of the process chain for the materials Cu-OFE and CuZn30. In addition, the influence of the sheet thickness, which has a major impact on the forming process and the material efficiency, is analyzed. The geometrical and mechanical component properties as well as the machine data are evaluated to assess the variables.

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 forming use-case. This paper presents a Hyperledger-Fabric-based blockchain network to fill this research gap. This network is specifically designed for the roll forming industry, while still aiming to meet general information exchange requirements. The roll forming use-case is divided into the material supply chain and a design/simulation workflow. Participants and parameters in these two data transfer chains have been validated with the help of industry experts. Running the conceptualized network on an on-premise server has allowed for a detailed evaluation. Feedback provided by experts of the roll forming industry shows the potential of the presented network. Furthermore, the presented solution covers requirements often neglected by existing approaches like large data handling, compatibility to existing interfaces, secure communication, and access rights definition. In summary, this paper provides a pioneering implementation and evaluation of a DLT-based solution for the roll forming industry and, therefore, a foundation for the next steps towards Industrie 4.0.

In the automotive industry, hot stamping has been established as a key technology for manufacturing safety-related car body components with high strength-to-weight ratio. During the forming operation, however, hot stamping tools are highly stressed by cyclic thermo-mechanical loads, which encourage the formation of severe wear and high friction at the blank-die interface. Against this background, an innovative surface engineering technology named laser implantation has been investigated for improving the formability of the parts and the efficiency of the hot stamping process. The laser implantation process is based on the generation of highly wear resistant microfeatures on tool surfaces by embedding hard ceramic particles via pulsed laser radiation. As a consequence, the contact area of the tool and thus the tribological and thermal interactions at the blank-die interface are locally influenced. In previous studies, the improved tribological performance of the modified tool surfaces has already been proven. However, the thermal interactions between tool and workpiece have not been analyzed, which in turn have a significant impact on the resulting part properties. In this regard, quenching tests have been carried out under hot stamping conditions by using conventional as well as laser-implanted tooling systems. Based on these results, Vickers hardness test and optical measurements have been performed on the quenched blanks, to qualify the mechanical properties and clarify the cause-effect relations.