The anisotropic mechanical properties of the aluminum alloy AlSi10Mg produced by laser beam melting (PBF-LB/M) were systematically investigated for five orientations between 0° and 90°. The combination of tensile tests, hardness measurements, density analyses, EBSD examinations, and fracture surface analyses shows that all samples have relative densities above 99.9%, so that porosity can be virtually ruled out as a factor influencing the mechanical characteristics. The strength values examined follow a clearly pronounced directional pattern with a maximum of 370 MPa at 0°, a clear minimum of 322 MPa in the range 45°-67. 5° and an increase to 353 MPa at 90°. EBSD analyses confirm that these mechanical trends are closely linked to the orientation of the melt pools, texture development, and epitaxial grain growth, which is characteristic of PBF-LB/M structures. Fracture surface analyses show a transition from homogeneous ductile fracture to orientation-dependent shear and lamellar structures, especially in intermediate angles. Despite the anisotropic microstructure, the global ductility remains largely constant. The results illustrate that the anisotropy of the mechanical properties is predominantly due to microstructural mechanisms and represents robust, reproducible material behavior.

Clinched joints with non-rotationally symmetric geometries exhibit orientation-dependent mechanical behavior that is commonly neglected in structural-scale simulations. Reuleaux triangle shaped clinched joints, in particular, show pronounced in-plane anisotropy depending on their orientation. While such effects have been studied at joint and specimen scale, their relevance at the structural level remains largely unexplored. In this work, the influence of joint orientation on the bending response of a joined structure is investigated using numerical simulations. A simplified joint replacement model based on the *CONSTRAINED_SPR2 point-connector formulation in LS-DYNA is employed, with parameters calibrated from previously obtained experimental force displacement data. A hat shaped profile structure subjected to three-point bending is analyzed in a parametric study considering variations in joint orientation, joint spacing, and profile geometry. The results show that joint orientation has little influence during the initial deformation phase but becomes increasingly significant at larger displacements, where joint behavior governs load transfer. Orientation dependent effects are found to influence the global force displacement response and local load redistribution among joints, with magnitudes comparable to those induced by changes in joint spacing and structural geometry. The findings confirm that joint orientation effects remain relevant at the structural level and should be considered in the design of structures assembled using non-rotationally symmetric clinched joints.

This study investigates a new method for enhancing the mechanical performance of clinched joints by filling the residual cavity with structural epoxy adhesive. Two adhesives (3M 07333 and Betamate 2098) with different Young’s moduli and multiple fill volumes were examined to determine how adhesive properties and cavity filling influence joint behaviour. Single-lap shear tests showed that adhesive filling increases peak force compared to unfilled joints, with the higher-modulus adhesive providing the largest improvement. Reducing the fill volume led to proportional reductions in shear strength, demonstrating that the joint response can be tuned through controlled cavity filling. In head-tension loading, adhesive filling increased peak force relative to unfilled joints, although variations in fill volume produced no significant change. All shear specimens failed by neck fracture, while cross-tension specimens consistently failed by pull-out, indicating that the adhesive modifies load capacity but not failure mode. The results demonstrate that cavity filling is an effective post-process reinforcement strategy that allows targeted adaptation of clinched joint behaviour without modifying the clinching process or geometry.

Over the past decades, the importance of lightweight structures in the aircraft and automotive industries has steadily increased due to regulations aimed at reducing global warming. Work hardened steel alloys are commonly used for lightweight applications, but they face stability issues when the material thickness reaches certain thresholds. Fiber Reinforced Plastics (FRP) offer a viable alternative due to their high strength-to-weight ratio, but they are often expensive due to long production cycles and high material costs. A feasible solution lies in hybrid lightweight designs that utilize expensive FRP materials only in highly stressed areas, achieving a balance between low mass and acceptable cost. These hybrid structures are lighter than metal components and more cost-effective compared to fully FRP structures, without compromising mechanical properties. This study focuses on producing rotationally symmetrical hybrid structures using Resin Transfer Molding (RTM) combined with vacuum assistance in a single-stage process. The research examines the effects of injection pressure, mold temperature, and the interface between metal and FRP. The mechanical characterization of these hybrid structures was conducted to assess their performance under torsion, compression, and interlaminar shear strength (ILSS) loading conditions. The results indicate that hybrid designs can offer a lightweight alternative without compromising mechanical properties.

This paper discusses the influence of joint orientation with non-rotationally symmetric geometry, on load distribution and structural behavior. The focus is on understanding how changes in the alignment of individual joints affect the distribution of load, neighboring joints, and the overall performance of the component. Lap shear specimens with multiple joints arranged in a line are analyzed to explore these effects. Simplified models are used to model the joints in finite element simulations, allowing for efficient yet accurate analysis of the load distribution and structural response under varying joint orientations. Variations in joint orientation result in measurable changes in the distribution of forces on adjacent joints, influencing their behavior and that of the overall assembly. Experimental validation confirms the numerical results, providing deeper insights into the interaction between individual joints and their surroundings. This work contributes to the development of systematic approaches for optimizing the design of components with non-rotationally symmetric joints. The study highlights the importance of considering directional properties of joints in designing structural components.

As global industries seek to reduce energy consumption and lower CO2 emissions, the need for sustainable, efficient maintenance processes in manufacturing has become increasingly important. Traditional mold cleaning methods often require complete tool disassembly, extended downtime, and heavy use of solvents, resulting in high energy costs and environmental impact. This study presents a novel localized ultrasonic cleaning process for injection molding tools that enables targeted, in situ cleaning of mold cavities without removing the tool from the press. A precisely positioned ultrasonic transducer delivers cleaning energy directly to contaminated areas, eliminating the need for complete mold removal. Multiple cleaning agents, including alkaline and organic acid solutions, were evaluated for their effectiveness in combination with ultrasonic excitation. Surface roughness measurements were used to assess cleaning performance over repeated contamination and cleaning cycles. Although initial tests were performed manually in the lab, results indicate that the method can be scaled up and automated effectively. This process offers a promising path toward energy-efficient, low-emission tool maintenance across a wide range of injection molding applications.

People with disabilities often rely on caregivers, which can impact their self-esteem and place a burden on caregivers. 3D printing, especially Fused Deposition Modeling (FDM), enables customized everyday aids that promote self-help. Advances in metallic filaments offer further improvements. This study explores practical examples of self-help, evaluating the potential of metallic filaments for enhanced manufacturing and their integration into series production.

The imperative for industrial decarbonization is underscored by political and sustainability requirements. Energy efficiency stands as a foundational pillar in the comprehensive strategy aimed at decarbonizing industrial processes. The heterogeneity and potential interdependencies of energy use in the manufacturing industry necessitates systematic methods and tools, especially in identifying energy efficiency potentials as well as deriving, assessing and prioritizing energy efficiency measures. To address these challenges, this study aims to review existing methods that prioritize decarbonization through holistic and systematic energy efficiency initiatives based on an introduced framework for holistic energy efficiency improvement. Due to the identified lack of holistic approaches in existing methods, this study ultimately proposes directions for future research. This includes the generic and modular modeling of energy demands at different manufacturing levels to identify the technical efficiency potentials, the automated and holistic derivation of energy efficiency measures based on energy efficiency analysis, and multi-criteria assessment and prioritization approach considering interactions between measures. In summary, the development of energy efficiency improvement methods as digitalized and standardized software components for systematic implementation is proposed to support the holistic improvement of energy efficiency and contribute to informed decision-making in the context of industrial decarbonization strategies.

Fibre-reinforced polymers are increasingly used due to their high specific strength, making them suitable for local sheet metal reinforcement. This allows improved overall mechanical properties with reduced wall thickness of the sheet metal part and, thus, lower weight of the components. One of the main focuses of research into such hybrid structures is on the adhesive properties and the respective failure behaviour of the interfaces. Generally, the failure behaviour under the influence of mechanical loads can be divided into adhesive, cohesive and mixed-mode failure. The correlation between observed failure behaviour and adhesion properties of the hybrid composite materials is analysed in detail in this work. The hybrid composite consists of an aluminium sheet of the alloy EN AW-6082 T6 and thermoset carbon fibre-reinforced plastic (CFRP) prepreg. The aluminium sheet was laser pretreated before hybrid production to improve the adhesion properties. The specimens studied were produced by the prepreg pressing process, in which the components are cured and joined simultaneously. The influences of the thickness of the CFRP part, the layup, the fibre orientation at the boundary layer, and the laser pretreatment parameters on the properties of the hybrid joints were investigated.

Currently, the need for resource efficiency and CO2 reduction is growing in industrial production, particularly in the automotive sector. To address this, the industry is focusing on lightweight components that reduce weight without compromising mechanical properties, which are essential for passenger safety. Hybrid designs offer an effective solution by combining weight reduction with improved mechanical performance and functional integration. This study focuses on a one-step manufacturing process that integrates forming and bonding of hybrid systems using compression molding. This approach reduces production time and costs compared to traditional methods. Conventional Post-Mold Assembly (PMA) processes require two separate steps to combine fiber-reinforced plastic (FRP) structures with metal components. In contrast, the novel In-Mold Assembly (IMA) process developed in this study combines forming and bonding in a single step. In the IMA process, glass-mat-reinforced thermoplastic (GMT) is simultaneously formed and bonded between two metal belts during compression molding. The GMT core provides stiffening and load transmission between the metal belts, which handle tensile and compressive stresses. This method allows to produce hybrid structures with optimized material distribution for load-bearing and functional performance. The process was validated by producing a lightweight hybrid brake pedal. Demonstrating its potential for efficient and sustainable automotive production, the developed hybrid brake pedal achieved a 35% weight reduction compared to the steel reference while maintaining mechanical performance under quasi-static loading

Injection molding plays a pivotal role in modern manufacturing, enabling the mass production of complex components with high precision. However, traditional tooling methods often face challenges related to thermal management, design constraints, and material efficiency. This study examines the use of additive manufacturing (AM) in the development and optimization of injection molding tools to overcome these limitations. A novel prototype was fabricated using AM techniques, incorporating integrated cooling channels and optimized lattice structures to enhance thermal performance and simplify the manufacturing process. Experimental validation demonstrated the prototype’s effective integration into a vacuum-assisted resin transfer molding (VA-LRTM) system without requiring modifications to existing tooling setups. The results showed significant improvements in temperature regulation, reduced cycle times, and consistent mechanical properties of the molded components compared to conventional approaches. By reducing the number of tool components and eliminating the need for support structures during manufacturing, AM also minimized material waste and post-processing requirements. This research highlights the transformative potential of additive manufacturing in injection molding tool design, offering increased flexibility, cost efficiency, and enhanced functionality to meet the evolving demands of modern industrial applications.

Additive manufacturing of metallic components often results in the formation of columnar grain structures aligned along the build direction. These elongated grains can introduce anisotropy, negatively impacting the mechanical properties of the components. This study aimed to achieve controlled solidification with a fine-grained microstructure to enhance the mechanical performance of printed parts. Stainless steel 316L was used as the test material. High-intensity ultrasound was applied during the direct energy deposition (DED) process to inhibit the formation of columnar grains. The investigation emphasized the importance of amplitude changes of the ultrasound wave as the system’s geometry continuously evolves with the addition of multiple layers and assessed how these changes influence the grain size and distribution. Initial tests revealed significant amplitude fluctuations during layer deposition, highlighting the impact of layer deposition on process uniformity. The mechanical results demonstrated that the application of ultrasound effectively refined the grain structure, leading to a 15% increase in tensile strength compared to conventionally additively manufactured samples.

The optimization of process parameters in powder Directed Energy Deposition (DED) is essential for achieving consistent, high-quality bead geometries, which directly influence the performance and structural integrity of fabricated components. As a subset of additive manufacturing (AM), the DED process, also referred to as laser metal deposition (LMD), enables precise, layer-by-layer material deposition, making it highly suitable for complex geometries and part repair applications. Critical parameters, such as the laser power, feed rate, powder mass flow, and substrate temperature govern the deposition process, impacting the bead height, width, contact angle, and dilution. Inconsistent control over these variables can lead to defects, such as poor bonding, dimensional inaccuracies, and material weaknesses, ultimately compromising the final product. This paper investigates the effects of various process parameters, specifically the substrate temperature, on bead track geometry in DED processes for stainless steel (1.4404). A specialized experimental setup, integrated within a DED machine, facilitates the controlled thermal conditioning of sample sheets. Using Design of Experiments (DoE) methods, individual bead marks are generated and analyzed to assess geometric characteristics. Regression models, including both linear and quadratic approaches, are constructed to predict machine parameters for achieving the desired bead geometry at different substrate temperatures. Validation experiments confirm the accuracy and reliability of the models, particularly in predicting the bead height, bead width, and contact angle across a broad range of substrate temperatures. However, the models demonstrated limitations in accurately predicting dilution, indicating the need for further refinement. Despite some deviations in measured values, successful fabrication is achieved, demonstrating robust bonding between the bead and substrate. The developed models offer insights into optimizing DED process parameters to achieve desired bead characteristics, advancing the precision and reliability of additive manufacturing technology. Future work will focus on refining the regression models to improve predictions, particularly for dilution, and further investigate non-linear interactions between process variables.

The use of hybrid materials as a combination of fibre-reinforced plastic (FRP) and metal is of great interest in order to meet the increasing demands for sustainability, efficiency, and emission reduction based on the principle of lightweight design. These two components can therefore be joined using the intrinsic joining technique, which is formed by curing the matrix of the FRP component. In this study, for the hybrid joint, unidirectionally pre-impregnated semi-finished products (prepregs) with duromer matrix resin and micro-alloyed HC340LA steel were used. In order to conduct a detailed investigation, the damage mechanisms of intrinsically produced fibre metal laminates (FMLs), a new clamping device, and a novel pressing tool were designed and put into operation. The prepregs were prestressed by applying a preloading force using a specially designed prestressing frame. Hybrid specimens were then produced and subjected to nanoindentation and a shear tensile test. In particular, the effect of the residual stress state by varying the defined prestressing force on the damage mechanisms was studied. The results showed that no fracture patterns occurred in the interface of the specimens without preloading as a result of curing at 120 °C, whereas specimens with preloading failed at the boundary layer in the tensile range. Nevertheless, all specimens cured at 160 °C failed at the boundary layer in the tensile range. Furthermore, it was proven that the force and displacement of the preloaded specimens were promisingly higher than those of the unpreloaded specimens.

Traditionally, joints are cylindrical and rotationally symmetric. In the present study, non-rotationally symmetric joints are used for joining steel and Glass mat-reinforced thermoplastic sheets (GMT). In addition, the study also analyzes the impact of non-rotational symmetric joint rotation on the load-bearing capacity. Single lap joint specimens were fabricated using the In-Mold assembly technique for joining steel sheets with GMT. Tensile shear tests were performed on different orientations of the joint geometry, and it was observed that changing the joint orientation influences the load-bearing capacity. The joints are constitutively modeled using beam elements and the influence of joint rotation on load distribution is examined through a static simulation study.

The corrosion behavior of a hybrid laminate consisting of laser-structured aluminum EN AW-6082 ∪ carbon fiber-reinforced polymer was investigated. Specimens were corroded in aqueous NaCl electrolyte (0.1 mol/L) over a period of up to 31 days and characterized continuously by means of scanning electron and light microscopy, supplemented by energy dispersive X-ray spectroscopy. Comparative linear sweep voltammetry was employed on the first and seventh day of the corrosion experiment. The influence of different laser morphologies and production process parameters on corrosion behavior was compared. The corrosion reaction mainly arises from the aluminum component and shows distinct differences in long-term corrosion morphology between pure EN AW-6082 and the hybrid laminate. Compared to short-term investigations, a strong influence of galvanic corrosion on the interface is assumed. No distinct influences of different laser structuring and process parameters on the corrosion behavior were detected. Weight measurements suggest a continuous loss of mass attributed to the detachment of corrosion products.

Additive manufacturing (AM) technologies enable near-net-shape designs and demand-oriented material usage, which significantly minimizes waste. This points to a substantial opportunity for further optimization in material savings and process design. The current study delves into the advancement of sustainable manufacturing practices in the automotive industry, emphasizing the crucial role of lightweight construction concepts and AM technologies in enhancing resource efficiency and reducing greenhouse gas emissions. By exploring the integration of novel AM techniques such as selective laser melting (SLM) and laser metal deposition (LMD), the study aims to overcome existing limitations like slow build-up rates and limited component resolution. The study’s core objective revolves around the development and validation of a continuous process chain that synergizes different AM routes. In the current study, the continuous process chain for DMG MORI Lasertec 65 3D’s LMD system and the DMG MORI Lasertec 30 3D’s was demonstrated using 316L and 1.2709 steel materials. This integrated approach is designed to significantly curtail process times and minimize component costs, thus suggesting an industry-oriented process chain for future manufacturing paradigms. Additionally, the research investigates the production and material behavior of components under varying manufacturing processes, material combinations, and boundary layer materials. The culmination of this study is the validation of the proposed process route through a technology demonstrator, assessing its scalability and setting a benchmark for resource-efficient manufacturing in the automotive sector.

To improve the mechanical performance and to address current shortcomings of adhesive bonds such as bond degradation due to aging, a pulsed laser surface pretreatment of the metal surfaces of aluminum AW 6082-T6 joints with epoxy adhesive E320 is investigated. The surface treatment of the specimens resulted in increased single-lap shear (SLS) strengths before and after hydrothermal aging in 80 degrees C hot water compared to non-pretreated reference specimens. In order to reveal the correlations of laser parameters, resulting surface morphologies and the SLS strength, differently laser pretreated surfaces were characterized at the micro- and nanoscale using optical and scanning electron microscopies. The surface enlargement was quantified with a digital image analysis of cross-sections prepared from the joint interfaces. An analysis of variances (ANOVA) of the SLS results indicated that the laser parameters power and pulse frequency were most critical for obtaining high SLS strengths. Pretreated joint surfaces with a high micro- and nano-surface enlargement and deep solidification structures provide high SLS strengths of up to 50 MPa and almost negligible aging losses of merely 4%. Undercut structures on the pretreated surfaces were found to be beneficial for the mechanical and aging properties when only limited micro- and nanostructuring was applied.

A parameter investigation for manufacturing a hybrid system through the prepreg pressing process was carried out within the scope of this work to achieve optimal adhesion properties. The hybrid specimen comprises an aluminium sheet of alloy EN AW 6082 in T6 condition and a thermoset Carbon Fibre Reinforced Plastics prepreg. The prepreg pressing process allows the curing reaction of epoxy resin and the joining process to occur simultaneously to avoid an additional bonding process step. The surface of the aluminium sheet was pretreated in advance using a pulsed Nd:YAG laser to enhance the bonding properties. In the first step, the shear edge tests investigated the adhesion properties achieved with different consolidation (temperature, time and pressure) and laser parameters. Then, 3-point bending tests were carried out to investigate the influence of the consolidation parameters on the mechanical properties of the Carbon Fibre Reinforced Plastics-laminate. In this way, the optimal parameter sets for manufacturing hybrid structures were determined.

The main work issue is to optimize the manufacturing of hybrid profiles bearing loads defined by the automotive application, based on the monitoring of the production quality using computed tomography (CT). This offers an efficient, accurate and non-destructive inspection of the products in terms of time and costs in order to prove the production quality. The investigated parts consisted of glass mat reinforced thermoplastic (GMT) 3D structures covered by aluminum straps (AA5754) with different thicknesses. They were manufactured at varied process temperatures by compression molding. The profiles quality was evaluated by CT, where the designed and actual dimensions were compared and the porosity and the fiber distribution inside the profiles were examined. In a next step, quasi-static three point bending tests were carried out on the produced profiles in order to evaluate the impact of the production effects on the mechanical behavior. First CT results showed an inhomogeneous distribution of the fibers in the matrix especially for the profiles fabricated at lower tool temperature. Pores were also found in the areas with low concentration of fibers. After bending, the cracks tended to propagate along the fiber orientation. Consequently, the main failure mechanisms consisted in inter fiber fracture and delamination of the aluminum strap.