• Journal of the Korean Society for Precision Engineering
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• v.22 no.2
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• pp.126-132
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• 2005

In this paper, an auto-design system is introduced for a stamping tool based on commercial computer aided design system with its drafting language. The auto-design system consists of tool oriented product design subsystem which modifies and configures the product drawing, tool concept design subsystem which make a design of the punches and their punching progression and parts design subsystem that makes automatic dimension. The system is applied to the mechanical design of the stamping tool. The main logic of the system is based on half-edge theory, a kernel for the 3 dimensional CAD system, which is applied to 2 dimensional drafting auto-design system. The auto-design system enables to conspicuously reducing the designing time of the tool. In addition, there is little drafting error that had been about 3% without auto design program. It is effective to reduce the development time for new products because of rapid designing time of the tools, standardization of the stamping tool and the drafting rule for the auto-design system. The auto-design system yields high efficiency of the tool manufacturing system.

• Transactions of Materials Processing
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• v.3 no.1
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• pp.84-96
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• 1994

Simulation of 3 dimensional large irregularly shaped stamping process by a dynamic approach, based on an explicit time integration scheme, has been shown to be highly efficient and robust in comparison to traditional, implicit, quasi-static ones. The objective of the work is to evaluate the results from explicit code in application to deep drawing of rectangular cup and stamping of automotive front fender, in which deformation, force, thickness distribution are calculated. The method of predicting spring back and formability by and explicit code are suggested and applied to the processes.

• Tribology and Lubricants
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• v.36 no.6
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• pp.350-358
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• 2020

Hot stamping is an effective and suitable process widely used in automotive applications, though critical issues such as the transfer of the coating materials and build-up of these materials on tool surfaces have been encountered. Past researches figured out the resultant wear phenomenon using pin-on-disc and drawing (for example, strip drawing and deep drawing) methods to mimic the process and analyzed the wear behavior with respect to the influencing factors such as surface coating, load, and roughness. Although the pin-on-disc is a conventional and widely-used method, it presented a methodological limitation when simulating the hot stamping process by forming a new blank each time, and hence, a drawing-based friction method has been proposed and developed. Each drawing method applies loads in a different way, resulting in a different wear behavior. Notably, the deep drawing process is most similar to the hot stamping process compared to other drawing methods. In this paper we present a review of the friction testing methods mimicking the hot stamping process and the associated wear behavior. This can be helpful in presenting a step-by-step approach and different perspectives on the wear behavior in the hot stamping process.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.19 no.3
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• pp.407-413
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• 2010

This paper reports on the research which analyzes acoustic signals acquired in progressive compressing, hole blanking, and burr compacting process. An acoustic sensor was set on the bed of hydraulic press. Acoustic signal is generated from progressive stamping process. First the signal acquired from the unit process; compressing, blanking or compacting, is studied by Fourier Transform and Short Time Fourier Transform. The blanking process emitted ultrasonic signal with more than 20kHz, but the compressing and compacting processes emitted acoustic signals with lower than 10kHz. The combined signals periodically acquired right after the tool grinding were then analyzed. 70-80kHz signals appeared in time-frequency domain, but not in the frequency domain, the magnitude of which was related to the tool wear. Short Time Fourier Transform made up for the Fourier Transform in analyzing the emitted signal for stamping process in the ultrasonic domain.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2009.10a
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• pp.499-500
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• 2009

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 1998.06a
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• pp.1-8
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• 1998

The explicit and implicit time integration methods are applied effectively to analyze sheet metal stamping processes, which include the forming stage and the springback stage consecutively. The explicit time integration method has better merits in the forming stage including highly complicated three-dimensional contact conditions. By contrary, the implicit time integration method is better for analyzing springback since the complicated contact conditions are removd and the computing time to get the final static state is short. In this work, brief descriptions of the formulation and the factor study for springback simulations are presented. Further, the simulated results for the S-rail and the roof pannel stamping processes are shown and discussed.

• Transactions of the Korean Society of Automotive Engineers
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• v.4 no.5
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• pp.16-25
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• 1996

In the present work a rigid-plastic finite element formulation using dynamic explicit time integration scheme is proposed for numerical analysis of auto-body panel stamping processes. The rigid-plastic finite element method based on membrane elements has long been employed as a useful numerical technique for the analysis of sheet metal forming because of its time effectiveness. A damping scheme is proposed in order to achieve a stable solution procedure in dynamic sheet forming problems. In order to improve the drawbacks of the conventional membrane elements, BEAM(abbreviated from Bending Energy Augmented Membrane) elements are employed. Rotational damping and spring about the drilling direction are introduced to prevent a zero energy mode. The lumping scheme is employed for the diagonal mass matrix and linearizing dynamic formulation. A contact scheme is developed by combining the skew boundary condition and the direct trial-and-error method. Computations are carried out for analysis of complicated auto-body panel stamping processes such as forming of an oilpan, a fuel tank and a front fender. The numerical results of explicit analysis are compared with the implicit results with good agreements and it is shown that the explicit scheme requires much shorter computational time, especially when the problem becomes more complicated. It is thus shown that the proposed dynamic explicit rigid-plastic finite element method enables an effective computation for complicated autobody panel stamping processes.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.46 no.4
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• pp.181-189
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• 2023

In this paper, we present a case study of developing MVIS (Machine Vision Inspection System) designed for exterior quality inspection of stamping dies used in the production of automotive exterior components in a small to medium-sized factory. While the primary processes within the factory, including machining, transportation, and loading, have been automated using PLCs, CNC machines, and robots, the final quality inspection process still relies on manual labor. We implement the MVIS with general-purpose industrial cameras and Python-based open-source libraries and frameworks for rapid and low-cost development. The MVIS can play a major role on improving throughput and lead time of stamping dies. Furthermore, the processed inspection images can be leveraged for future process monitoring and improvement by applying deep learning techniques.

• Transactions of Materials Processing
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• v.7 no.6
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• pp.586-593
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• 1998

In recent automotive industries there has been significant increase in applications of computer simulation to the manufacturing of stamping dies for inner and outer body panels which greatly affect durability and aesthetic quality of automobiles. Enhancement of die quality and reduction of total die manufacturing time and consequently manufacturing cost are the visible outcome. However to successfully apply the result of simulation by a commercial package to the die manufacturing development of an optimal die manufacturing process is required upon the completion of analysis of forte and shortcoming of available sheet metal forming softwares. Based on the results of numerical analysis of front door outer panel forming. this paper evaluates the applicability of simulation results to the real die manufacturing for automotive body panels. Also it attempts to select an optimal die manufacturing process including design machining and tryout. Lastly it discusses the expected effects by adopt-ing the selected process in a real stamping die manufacturing facility.

• Journal of the korean Society of Automotive Engineers
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• v.15 no.3
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• pp.96-110
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• 1993

A procedure has been developed so that a die-face for stamping automobile outer panels can be design and modelled efficiently. The procedure is composed of four parts each of which corresponds to modeling major components of a die-face, i.e. tipped product, blankholder, draw beads, and step draw. The modeling techniques developed specifically for die-face design enable a designer to generate the shape of a die-face quickly with the minimum input, and the resulting models can be used in FEM analysis and NC tool path generation. This will lead to the reductions in lead time and manhours required for the design and manufacture of the stamping dies.