Research Projects
Laser-assisted clinching for adjusting electrical connection properties by influencing contact conditions—triboclinching
The clinching joining process currently exhibits limited adaptability in its electrical connection properties. This limitation complicates its use in components requiring electrification as part of CO₂-neutral production. Adaptable electrical conductivity values of connections are of particular importance for applications related to the energy transition. In the SFB/TRR285 project, correlations between bonding mechanisms and the mechanical, thermal, and electrical properties of clinched joints were investigated. The results showed that the contact conditions between the joining partners significantly influence the joint quality. By modifying the tribological system in a targeted manner—for example, by cleaning the joining parts—the electrical conductivity was significantly improved. These findings open up new possibilities for the targeted adjustment of joint quality. However, a process-integrated method for influencing the contact conditions during joining is currently lacking for industrial implementation. In collaboration with TOX® PRESSOTECHNIK, a laser-assisted low-temperature clinching process is therefore being developed to enable control of electrical conductivity in a targeted manner. The evaluation of the joining properties and the development of supporting software are being carried out in collaboration with Tiwa Quest and are intended to advance the industrialization of the research results.
Contact person: Christian Steinfelder
Manufacture of bipolar plates for fuel cells using laser-assisted hollow embossing rolling “BiPwalz”
The BMWK’s national hydrogen strategy forecasts a demand of over 25 TWh of H₂ by 2050. To avoid imports and ensure energy supply independence, the production and costs of fuel cells (FC) and electrolysers (EC) must be reduced. Bipolar plates (BiP) are a major cost driver, accounting for 20–30% of total costs. Due to thin sheet thicknesses (75–100 μm) and strict tolerances, their manufacturing is particularly challenging.
The project investigates the bipolar plate (BiP) of a low-temperature PEM cell capable of both generating energy from (green) hydrogen and splitting water. A new process combining hollow embossing rolls and laser treatment is being developed to reduce springback. The goal is continuous, precise manufacturing on an industrial scale at approximately 120 BiPs per minute, with lower tooling costs, less rework, and good integration into roll-to-roll processes.
Contact person: Christian Steinfelder
Automated Greenhouse Gas Accounting for Small and Medium-Sized Enterprises - Auto GHG Balance
As part of the Green Deal, the EU is calling on its member states to become climate-neutral by 2050. A key instrument for achieving this goal is the recording of the greenhouse gas (GHG) footprint of large companies (>1,000 employees). Consequently, this complex accounting is not mandatory for SMEs, but is indirectly passed on to them through the Supply Chain Due Diligence Act (Supply Chain Act for short). The goal of the project is to automate GHG accounting in order to reduce the financial and personnel burden on SMEs in the metalworking industry. The intended project outcome is an innovative technology capable of automatically calculating product- and company-specific GHG inventories. Initially, the technology will be used for 3D metal printing (3DMD), turning, and milling. This selection of manufacturing processes will initially cover approximately 50% of all metalworking. The technology’s modularity allows for the possibility of expanding its application to additional manufacturing processes. The technology will be integrated into a proprietary software tool as a demonstrator. The software tool generates a valid manufacturing plan from a component’s CAD model and calculates the corresponding planning data. The corresponding GHG value is calculated for each manufacturing step. This alleviates the burden on companies that lack the resources or expertise for GHG accounting.
Contact person: Sebastian Langula
Experimental and numerical analysis of forming-induced residual stresses in a targeted manner to improve fatigue strength in high-cycle-loaded pure copper components
Component failure due to cyclic loading plays a crucial role in nearly all industrial applications. To prevent failures, the behavior under cyclic loads must be taken into account in the design process. Building on methodological findings from a DFG project jointly conducted by the applicants within the framework of DFG-SPP 2013, a systematic investigation of components manufactured by forming from high-purity copper sheet will be carried out in cooperation with ZF Friedrichshafen AG (ZF), a systematic investigation of components manufactured by forming from high-purity copper sheet will be conducted. As an example, busbars produced by bending processes will be used. The effects of the forming process on the residual stress state, as well as on local material properties and the resulting fatigue strength of the component form the core of the project. The focus is on adjusting the residual stress state in a targeted manner to improve fatigue strength.
Contact person: Christian Steinfelder
Forming and Welding Technology for Energy-Efficient and Resource-Conserving Manufacturing of Metallic Bipolar Plates – UmKE
The success of the carbon-neutral hydrogen economy depends largely on the manufacturing capacities and costs of fuel cells and electrolysers. Metallic bipolar plates (BPP) account for 70–80% of the manufacturing costs of a fuel cell stack. In addition to material costs (approx. 55%), manufacturing expenses, together with tooling costs, are a major factor. The goal of this project is to develop robust, high-throughput, automatable, and scalable manufacturing technologies for metallic BPPs. The research focuses on forming, joining, and process modeling. Forming the thin foils presents a major challenge, which is exacerbated by additional requirements for joint-compatible design. The forming process is to be reliably implemented using vibration-superimposed stamping. Welding the 50 μm thin half-shells is equally challenging and is to be carried out within a few milliseconds using robust capacitor discharge welding. Since this method can only produce point-shaped, electrically conductive welded joints, thermal direct joining is being researched in a separate subproject for sealing the BPP. Compared to the laser welding used to date, this approach offers economic (significantly reduced production times with much lower equipment costs) and technical advantages (less heat input and thus less warping and minimal surface degradation).
Contact person: Christian Steinfelder
Process technology and equipment for automating the preparation of joint areas in plastic-coated pipes (KMR) for the efficient expansion of district heating networks - KMR-VerA
District heating networks make a significant contribution to the efficient use of energy resources and are to be expanded at an accelerated pace. The approximately 350 companies in Germany that expand and maintain the district heating network cannot even begin to meet the demand. Annual growth rates of 9% and higher can only be achieved through increased productivity while maintaining or improving quality, in order to reduce maintenance requirements in the long term. The most important component in network expansion is plastic-coated pipes (KMR), which require significant manual effort on-site to prepare for joining. With (partially) automated joint preparation, we aim to cut the current preparation time in half. This will increase productivity by the same margin and enable savings in the total construction volume for Germany of up to €3 million per year. With our device for (partially) automated joint preparation of plastic-coated pipes, we aim to achieve annual savings potential of at least €5,000 per company. The goal of this project is the necessary process and product development.
Contact person: Christian Steinfelder
SPP2476 - Method development for the multi-criteria optimization of a process chain for the production of hybrid lightweight components
The subject of this project is a four-stage process chain for the manufacture of a lightweight helmet made of an Al/Mg/Al sandwich structure. The properties that can be adjusted within technologically relevant limits and are relevant in the context of a backward-design approach are component weight, stiffness, dimensional accuracy, and the resulting carbon footprint. Due to the large number of directly controllable parameters along the process chain for adjusting the four evaluation criteria mentioned above and the mutual interactions between these parameters, the process chain “roll cladding–sheet cutting–deep drawing–laser cutting” is ideally suited for reverse-engineering or comprehensive process chain optimization.
Contact: Christian Steinfelder
Sustainable Electric Architecture Casings: EAC+
The goal of the EAC+ project is to develop recyclable, sustainable, economically and technically competitive housing structures that have high potential for application across a wide range of industries while simultaneously meeting the stringent electromagnetic requirements of electric mobility. This will be demonstrated using one of the most technologically sophisticated components of electric vehicles: the housing of the traction inverter. In the long term, the plan is to apply the technology to the housings of DC/DC converters, chargers, battery housings, etc. Together with the EAC+ project partners, a new type of hybrid injection molding is being developed. EAC+ technology makes it possible to replace conventional aluminum housings with economically attractive and sustainable components featuring an intelligent material mix.
Contact person: Christian Steinfelder
2nd Life Metal Component – Upcycling through Remanufacturing
While issues surrounding energy resources have received significant attention in recent years, material resources often go unnoticed, even though both types of resources are essential for sustainable manufacturing technology. Industrialized nations, in particular, have a very high demand for materials—especially metals—which cannot be met solely through the energy-intensive production of new materials or through existing recovery strategies such as recycling. Therefore, in the future, goods currently in use must be utilized directly as raw materials. The energy-intensive recycling step involving remelting is eliminated in this process and replaced by the direct reuse of the material. Currently, however, production technology is not equipped for this novel method of raw material extraction, meaning that no adequate process routes or chains exist to enable the processing of these resources. This is where the research project comes in, aiming to develop a practical process route for the largest share of metallic components—sheet metal parts—in which the fields of laser processing, material characterization, forming, and planning work together in a complementary manner. As a result, it should thus be possible to sustainably manufacture a new component consisting of 75% materials that have already been used at least once, without a traditional recycling step:
¾ previously used component + ¼ new semi-finished product ⇨2nd Life Metal Component
Contact person: Christina Guilleaume
Automated removal of 3D metal printing supports via milling - AutoSupport
This EU-funded project is a collaboration with H+E Produktentwicklung GmbH. The goal of this project is the joint development of an innovative technology for the automated removal of supports in 3D-printed metal components via 5-axis milling to increase production capacity automation while simultaneously reducing production costs. The project aims to apply the latest research findings to solve a previously insurmountable problem of great economic significance.
Contact person: Sebastian Langula
Transregio TRR285 - Method Development for Mechanical Joining in Adaptable Process Chains
By researching scientific methods in the field of joining technology that lead to the establishment of efficient and resource-conserving process chains amid product diversity, different materials, and construction methods, the SFB/Transregio is addressing an exciting and timely topic. Given the volatile demands of industry and consumers, as well as accelerating development cycles in a globalized world, adaptability is one of the central themes of modern production technology
Further information can be found on the TRR285 website
Contact person: Christian Steinfelder
Thermomechanical ring rolling with predictive property control
Thermomechanical tangential profile ring rolling (TMR) is a process for manufacturing ring geometries close to the final contour while simultaneously and in a targeted manner influencing the microstructure and hardness through controlled process guidance regarding deformation and temperature. A combined approach using PID and predictive models is employed for this purpose, enabling the existing process window to be utilized in such a way that the target values for final geometry, microstructure, and hardness can be achieved simultaneously. Following validation on the actual machine, it will be possible to transfer the control strategy for geometries and configurations to cases that cannot be realized on the existing rolling mill. An analysis of the process and system performance is intended to enable the derivation of design principles and rules regarding the system architecture (actuators, sensors, modeling, and control) for the implementation of thermomechanically controlled ring rolling.
Further information can be found on the SPP2183websiteSPP2183 website
Contact person: Christian Steinfelder
Complementary data generation for machine learning for quality prediction using the example of ring rolling
To use machine learning for manufacturing processes such as radial-axial ring rolling, datasets of good and scrap parts must be collected. This requires balanced datasets in terms of the ratio of good to scrap parts. However, this is not the case with industrial data, which is why the project employs the method of data augmentation using synthetic data generated via simulation. In the field of radial-axial ring rolling, there is no fast, analytical simulation capable of generating a sufficiently large number of synthetic datasets featuring “rolls with form or process defects.” For this reason, the research question being investigated is to what extent a similar process can be examined for transfer to radial-axial ring rolling.
Contact person: Christian Steinfelder
Development of a process for forming aluminum sheet materials at cryogenic temperatures
Lightweight materials such as aluminum alloys play an important role in weight reduction. However, their limited formability at room temperature poses a major challenge and restricts their use. Significant improvements in formability can be achieved, for example, through stress-relief annealing or hot forming with multiple process steps. However, this improvement in formability comes at the expense of various positive properties such as strength, component quality, or cost. To avoid this, aluminum sheets can be formed at cryogenic temperatures, with the limit for maintaining these positive properties being the focus of the research proposed here. The project addresses the combination of cryogenic sheet forming with the macrostructuring of the die and hold-down device during deep drawing. A special, wave-like geometry of the forming tools minimizes the contact area between the sheet and the tool to suppress heat flow and thus the heating of the sheet. Furthermore, the local threshold temperature of the sheet metal must be determined, at which the advantages of the cryogenic material properties of aluminum alloys come into play.
Contact person: Christian Steinfelder
Resilient Deep Drawing Using Macrostructured Tools
The approach of using macrostructuring in the flange area to stabilize the deep drawing process and increase robustness against variable input parameters is beneficial across all sheet metal processing industries and in the associated toolmaking sector. The central goal is to make the results achieved in basic research fully available to industrial users. The methodology provided has extremely high potential for implementation in the challenging industrial environment, as it addresses two of the main problems faced by companies. On the one hand, the robustness of deep-drawing processes is highly relevant because it improves material utilization, minimizes scrap production, and prevents damage to costly tools. On the other hand, given high cost pressures and ever-shorter timeframes between product evolutions and new developments, it is critical to translate these into safe processes quickly and reliably.
Contact: Christian Steinfelder
Automated Production Costing – AFK
The goal of this R&D collaboration project is to develop a technology for automated production costing to drastically reduce the effort required for calculating planned times and production costs—a task that is always necessary in machining. To this end, the project aims to achieve fully automated production costing. The technology is intended to enable cost-effective, reliable, and highly efficient planning of machining operations. The approach dispenses with the manual methods of production costing that have been standard practice to date and determines production costs directly and fully automatically from the CAD data of the components, which is already available. To this end, the planned R&D project digitizes existing manufacturing knowledge and automatically applies it to the existing data set (CAD data). The proposed solution enables companies to access manufacturing expertise without needing their own production costing department.
Contact person: Sebastian Langula
Development of an automated manufacturability analysis accompanying the design process based on CAD data - Manufacturability Analysis
The goal of the project is to develop a method for the automated, design-accompanying provision of information to the designer, enabling them to reduce the costs of machining the component they have designed already during the design process. The designer plays a key role in the product development process (PDP), as approximately 85% of all subsequent costs are determined during the design phase. Early detection of a design that is not suitable for manufacturing reduces the costs for the entire product in a sustainable and cost-effective manner.
Contact person: Sebastian Langula