A precise production of sheet metal parts has always been a main goal in press shops. Highest quality demands are required especially in automotive production. Unfortunately, even today, the ...production is not optimal due to an ineffective approach to the springback compensation. Springback results in geometrical shape inaccuracies of the obtained product. Based on the current approach, excessive time and financial costs emerge due to corrections on the press tools. However, these corrections do not always lead to a better accuracy of the stampings. The main objective of the research is to design a modified solution of the current approach. The modified solution is designed as a methodology with a focus on the analysis and compensation of the springback with a help of a numerical simulation. To achieve the main goal, smaller sub-goals are employed. These sub-goals, or rather experiments, mainly focus on parameters, which, more or less, influence the springback phenomenon. The designed methodology is verified with real car body parts and is carried out with a help of the department of the press tools design in ŠKODA AUTO, a.s. There, the methodology is used for improving the accuracy of the stamping process of the car body parts and for improving the quality of the final product.
In recent decades, the automotive industry has had a constant evolution with consequent enhancement of products quality. In industrial applications, quality may be defined as conformance to product ...specifications and repeatability of manufacturing process. Moreover, in the modern era of Industry 4.0, research on technological innovation has made the real-time control of manufacturing process possible. Moving from the above context, a method is proposed to perform real-time control of a deep-drawing process, using the stamping of the upper front cross member of a car chassis as industrial case study. In particular, it is proposed to calibrate the force acting on the blank holder, defining a regulation curve that considers the material yield stress and the friction coefficient as the main noise variables of the process. Firstly, deep-drawing process was modeled by using commercial Finite Element (FE) software AutoForm. By means of AutoForm Sigma tool, the stability and capability of deep-drawing process were analyzed. Numerical results were then exploited to create metamodels, by using the kriging technique, which shows the relationships between the process parameters and appropriate quality indices. Multi-objective optimization with a desirability function was carried out to identify the optimal values of input parameters for deep-drawing process. Finally, the desired regulation curve was obtained by maximizing total desirability. The resulting regulation curve can be exploited as a useful tool for real-time control of the force acting on the blank holder.
This paper deals with the problematics of fixation of hemmed joints, especially with one specific mechanical method how to ensure a dimensional stability of a hemmed joint of car-body parts, such as ...doors, bonnet and trunk lid, during the production process in the automotive industry. It also evaluates simulations and verify the possibility of the use of the Autoform software for this problematics. In the paper, the possibility of using the law of similarity in the analysis of the compressibility of small parts by Autoform is described.
Ultra-high-strength steels (UHSS) combined with tailor-stamping technologies are increasingly being adopted in automotive body production due to crashworthiness improvements and part weight ...reduction, which meet safety and energy saving demands. Recently, USIBOR®2000 (37MnB5) steel has been added to the family of UHSS. This new material allows higher performance with respect to its predecessor USIBOR®1500 (22MnB5). In this work, the two steels are compared for the manufacturing of an automotive B-Pillar by press-hardening with a tailored tool tempering approach. A Finite Element (FE) model has been developed for the numerical simulation of thermomechanical cycles of the press-hardening process. The FE-simulations have been performed with the aim of obtaining soft zones in the part, by varying the quenching time and the temperature of heated tools. The effects of these parameters on the mechanical properties of the part have been experimentally evaluated thanks to hardness and tensile tests performed on specimens subjected to the numerical thermo-mechanical cycles using the Geeble-3180 physical simulator. The results show that for both UHSS, an increase in quenching time leads to a decrease in hardness up to a threshold value, which is lower for the USIBOR®1500. Moreover, higher mechanical resistance and lower elongation at break values are derived for the USIBOR®2000 steel than for USIBOR®1500 steel.
Machine learning (ML) technologies are emerging in Mechanical Engineering, driven by the increasing availability of datasets, coupled with the exponential growth in computer performance. In fact, ...there has been a growing interest in evaluating the capabilities of ML algorithms to approach topics related to metal forming processes, such as: Classification, detection and prediction of forming defects; Material parameters identification; Material modelling; Process classification and selection; Process design and optimization. The purpose of this Special Issue is to disseminate state-of-the-art ML applications in metal forming processes, covering 10 papers about the abovementioned and related topics.
The aeronautical industry is moving from high-capacity large-airplane construction to low-capacity small-airplane construction. With the change in the production volume, there is a need for more ...efficient manufacturing processes, such as stamping/deep drawing. However, the streamlined shape and exotic materials of airplanes pose a challenge to accurate numerical simulation of the manufacturing processes. In the case of the Inconel 718 material, researchers previously proposed numerical models; however, these models failed to take account of some key parameters, such as the degradation of the elastic modulus and intermediate annealing thermal processes. The aim of the present study was to characterize the Inconel 718 material, with and without intermediate annealing thermal treatment (TT) and to propose a suitable model. To evaluate the accuracy of the proposed model, a U-drawing benchmark test was used.
The micro-sandwich sheets with metallic/polymer fibrous core have been pointed out as one of the most promising technological solutions to the automotive industry. However, due to the lack of ...understanding of certain fundamentals related with the mechanical behavior of micro-sandwich sheets during forming processes, the transfer and scale-up of this promising technology to industry has been limited. A challenging aspect in the experimental characterization of these materials is related with the unknow properties of the composition of the core which consist of metallic (polymer) fibers and adhesive. In general, the suppliers of monolithic metal sheets also make available the respective datasheets with the mechanical and chemical properties. These datasheets use to refer the minimum, maximum or a specific tolerance range (dependent of the grade material) to the mechanical properties. However, the micro-sandwich sheets are not provided with this mechanical and chemical data, at least, for all layers. Therefore, it is missing a simple and robust methodology to supply the mechanical properties of the total micro-sandwich sheet to the industry. Furthermore, there is no study about the different numerical approaches available in the commercial stamping softwares to modelling and simulate micro-sandwich materials. In this work, a strategy to deduce the unknown mechanical properties of the fibrous core from symmetric or asymmetric micro-sandwich sheets, i.e., with the same or different skin thickness, is presented. For true stress-strain curves and anisotropy purposes, uniaxial tensile tests in 3 different directions, according ISO 6892-1:2009 standard, were performed. Total micro-sandwich specimens and skin specimens were tested. The mechanical properties of the core were deduced from micro-sandwich and skin’s mechanical properties. Based on this data, the constitutive model was established. Additionally, 6 different Nakazima geometries were punched according to ISO 12004 for formability assessment. Experimental Forming Limit Curves (FLC) and principal strains data were recorded during the tests thanks to a high-resolution cameras and software GOM ARAMIS. Finally, the experimental mechanical tests were virtually reproduced with both commercial codes AutoForm R5.2 and PAM-STAMP 2G 2015.1. Thus, different modelling strategies and Finite Element Method (FEM) approaches were compared. The excellent agreement between numerical and experimental results demonstrate the accuracy of the applied methodology.
Describe an advanced design and manufacturing technology Concurrent Engineering (CE) and give the automobile covering parts mould development flow basing on concurrent engineering. It tries to ...consider initially all factors of the mould development life cycle. Take an automobile covering part for example. Basing on the finite element analysis software AUTOFORM, do die design and forming simulation. According to the result of simulation, designer can predict the defect of forming and timely modify the forming process. So in stage of process design taking into account the blank forming, this kind of concurrent design of the mould surface can be directly used to mould design, also won't return after the mold design to modify the die-face design process. So on account of concurrent engineering, it can reduce the changes of automobile covering parts mould design and the number of repeated test, improve quality, reduce cost, and shorten the cycle of mould development.
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