Papers by Keyword: Deep Drawing

Abstract: In the early concept phase of vehicle development, crash simulations must provide reliable statements on energy absorption and failure behavior, although detailed forming simulations and process data are typically not yet available. Manufacturing-induced material states, such as plastic pre-strains and local sheet thickness distributions, are therefore often neglected or approximated using simplified low-fidelity approaches with high uncertainty. This contribution introduces UmMatCraML, a data-driven medium-fidelity method for rapid initialization of typical crash shell meshes (element edge lengths 3–5 mm) with forming-induced field variables. Starting from the final component geometry, a purely geometric unfolding is performed to approximate the blank, from which a mesh-and coordinate-independent areal strain (A_r) is determined. A monotonicity-preserving gradient boosting regressor subsequently compensates for systematic deviations of this geometric surrogate model compared to high-fidelity deep drawing simulations, with four Hockett-Sherby parameters consistently parameterizing the material description. The training data are generated from approximately 5,000 LS-DYNA forming simulations and cover a broadly varied, physically consistent parameter space. In validation on a demonstrator part, UmMatCraML reduces the computation time for determining forming-induced component properties from about 60 min for High-Fidelity-Simualtion (HFS) or 10–15 min for Low-Fidelity-Simulation (LFS) to under 10 s, with simultaneously improved prediction quality. Demonstrations on components of a Toyota Yaris full-vehicle model show robust predictions even with trimming and perforations. Limitations arise from the model assumptions made (e.g., isotropic hardening, limited mapping of multi-stage process paths). Overall, UmMatCraML enables real-time, reproducible provision of manufacturing-induced field variables for concept crash simulations without explicit tool modeling.

Abstract: This study investigates the structural response of blank-holders (BHs) equipped with spatially distributed magnetorheological (MR) actuators for adaptive deep drawing. While MR actuators provide fast, independent, and high-resolution force modulation, their effectiveness depends critically on the BH’s ability to transmit spatially differentiated loads without excessive diffusion or unrealistic stress localization. The relationships between BH stiffness, actuator spacing, and pressure localization at the sheet interface remain only partially understood, limiting the implementation of distributed blank-holding strategies. To address this gap, a comprehensive finite element (FE) framework is developed, combining a full closed-cup deep-drawing model with a complementary simplified configuration that isolates local deformation mechanisms under single-actuator loading. Parametric analyses examine the influence of BH thickness, local actuator force, and actuator spacing on stress distribution, localization radius, and overlap between adjacent load paths. Results show that BH thickness is the dominant factor governing spatial resolution: thinner BHs enable sharp pressure localization, whereas thicker ones diffuse local loads and suppress stress peaks. The spacing between actuators must therefore be selected as a function of BH stiffness to avoid stress-free regions while preserving distinct pressure footprints. For the reference industrial configuration (60 mm BH thickness), an actuator spacing of approximately 150 mm achieves the optimal compromise between localization capability and continuous sheet support. The proposed framework establishes quantitative design criteria for BH geometries compatible with MR-based adaptive forming and supports the development of next-generation blank-holding systems offering enhanced process stability, reduced scrap, and improved material-flow control.

Abstract: To produce functional cups by press forming, clad cups with a corrugated structure with voids like the cross section of corrugated cardboard were formed. Deep drawing, which is one type of press forming, is a plastic processing technology that forms thin sheets into three-dimensional containers. In the experiment, pure titanium TP270 and ultra-low carbon steel SPCC were used as test materials. The blank sheet thickness was 0.3 mm and the diameter was 80 mm to 90 mm. To form the corrugated cup, the roller ball die with steel balls installed on the shoulder of the die was prototyped. The steel balls were made of bearing steel JIS-SUJ2 and had diameters of 6.4 mm and 7.5 mm. The corrugated clad cup was formed by the composite die combined with a conventional die. Three conventional dies and two roller ball dies were used to obtain two corrugated layers with voids. The lubricant was a tool oil containing molybdenum disulfide powder. The sheet thickness strain distribution and residual stress distribution of the cup were evaluated. No destruction of the cup occurred during deep drawing. A regular wavy structure was observed in the cross section of the cup. The maximum reduction in the cup thickness was approximately 10 %. The residual stress on the outside of the cup was tensile stress from the bottom to the opening of the cup. The composite die made it possible to form a functional cup.

Abstract: Al-Si-Mg alloy strips with a Si content ranging from 0.5% to 12% were cast using a vertical type high-speed twin-roll caster at a roll speed of 60 m/min. The effect of Si content on ripple marks and cracks on the cast surface, as well as center cracks (crocodile cracks), was investigated. The results show a relationship between the Si content and these defects. When the Si content was higher than 4%, surface cracks and center cracks did not occur. However, ripple marks worsened when the Si content ranged from 3% to 5%.

Abstract: This study explored the capability of sheet forming of JIS ADC12 aluminum alloy, commonly used for die casting. Despite the poor ductility of ADC12, we attempted to improve this property by applying rapid solidification through an unequal diameter twin roll caster. A strip with a thickness of 3.7 mm was cast at a speed of 20 m/min. The as-cast strip was then cold rolled and annealed to investigate its sheet-formability by deep drawing, three-roll bending and V-bending. This research also investigated the elements of ADC12 that contribute to poor ductility, with a focus on the impact of Mg, Cu, Fe, and Zn during the deep drawing process.

Abstract: Deep drawing process is a common sheet metal forming technique in motor vehicle manufacturing. There are three primary defects that could be occur in deep-drawn parts: tearing, wrinkling, and thinning. When the thinning is difficulty detected by visual inspection. As a result, this study aims to address the thinning issue in a fuel tank part made from an aluminum alloy sheet AA5754-O 1.5 mm thick under cold working deep drawing process, while the manufacturer's desired upper limit for thinning is 20%. Two influential parameters viz. blank holder force and initial size of blank, were investigated and optimized by using Finite Element Analysis (FEA) through PAM-STAMP simulation software with the validated material model was based on Hill’s 1948 anisotropic yield criterion with Swift hardening law. The mechanical parameters in the mentioned model were derived from the results of uniaxial tensile tests. In conclusion, both the hydraulic cushion's blank holder pressure and the initial size of the blank were found to influence the thinning of the part, either individually or in combination. Despite optimizing both parameters, they were unable to consistently achieve the desired limit.

Abstract: Forming conditions for deep drawn SUS304 square cups having no delayed cracks are determined using finite element (FE) simulations based on the threshold % of wall thickening for delay cracking obtained from deep drawing tests of SUS304 cylindrical cups. The maximum drawing ratio and the initial blank thickness are fixed at 1.87 and 0.8 mm, respectively in this study taken into the considerations of the capacity of the press machine i.e., 100 kN. The blank holding forces (BHF), punch corner radius, r_p and die corner radius, r_d are varied to obtain 75 mm x 75 mm square cups having % of local thickening less than the threshold value i.e., 47% in the cracking zones located adjacent to the top corners of the cups. A quarter 3D FE simulation model of the deep drawing process is constructed, the wall thickness distributions of the cups are calculated. The simulation results showed that the forming conditions for the crack-free cups could be obtained with BHF ≥ 47 kN, r_p ≥ 8.5 mm and 6.8 mm ≤ r_d ≤ 9.5 mm. A method for designing the forming conditions of deep drawn SUS304 square cups is proposed in this study.

Abstract: The formability of sheet-metal with a folding-bottom circular hollow tube has been studied both by numerical simulation and experiment. A mesh-convergence analysis has been carried out to determine an optimum element size for purposes of numerical simulation. The geometry and dimension of the dies and of the punch are designed to simulate the multi-stage deep drawing operation to take place. During the deep drawing operation, the strains of the sheet blank are always located in the second quadrant of the forming limit diagrams, and it continuously moves in a linear state to the left side of the diagram. At the final stage, the tube is drawn to a certain height without evidence of fracture. In order to obtain a quality product, an optimization of input parameters for the deep drawing operation is conducted using Taguchi method. Finally, a validation test is also employed to demonstrate the accuracy of forming processes. The result reveals sufficient agreement in both geometry and dimension between simulated and actual tubes to meet a good quality standard.

Abstract: In this study, the influences of temperature variation in deep drawing process are investigatedby changing the temperatures of the whole blank, a part of the blank, the punch and die fordifferent yield criteria and hardening models. Von-Mises criterion with isotropic, kinematic and combinedhardening and, Hill48 and Yld2003 yield criteria with isotropic hardening are considered toform the constitutive relations. Circular, square and complex shaped parts made of AA5754 materialare used in the numerical analyses. The local heating simulations are conducted for circular blanksand the drawability of the parts are evaluated by using the Johnson-Cook failure criteria. Hot formingand quenching and local heating analyses are also carried out for a complex shaped part. The resultsobtained by the finite element analyses for different constitutive equations are compared with eachother and experimental results according to thickness strain distribution, punch force variation andrim shape of the deformed blanks.

Abstract: Aluminum materials are popular materials for research in terms of lightweight construction. How cryogenic forming can be used to increase material utilization in terms of resource efficiency is one of the areas being investigated. Subject of this study are numerical and experimental investigations regarding the formability of the aluminum alloy AA6014-T4 with macro-structured deep drawing tools at cryogenic temperatures. The macro-structure of the deep drawing dies significantly reduces the heat flux between the dies and the blank due to the reduced contact area. For this reason, active cooling or heating of the dies is not required. The process of heat conduction between the tool and the blank, as well as the deep drawing process, is calculated using the FE-method and compared with the experimental investigations. In addition, the induced residual stresses are determined using the hole-drilling method and compared with the computational solution. The presented examination shows an improved deep drawing ratio of the aluminum alloy AA6014-T4 at cryogenic blank temperature without active tool cooling. Additionally, the influence of the blank temperature on the forming regarding the residual stresses in the cups is analyzed and discussed.