• Transactions of Materials Processing
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• v.21 no.3
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• pp.186-194
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• 2012

Hot stamping is a forming method that offers various advantages such as superior mechanical properties, good formability, and very small springback. However, relatively large-sized parts, such as front pillars, exhibit poor formability when hot stamped due to the limited material flow and thickness reduction imparted by the process. This reduction in thickness can also lead to cracks. One of the reasons is the relatively high friction between the sheet and the die. In this study, in order to obtain the optimal conditions for hot stamping of front pillars, various process parameters were studied and analyzed using the sheet forming software, J-STAMP. The effects of various parameters such as the die structure, blank shape, blank holding force, punch speed, clearance(upper and lower dies) and distance block were analyzed and compared.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2005.10a
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• pp.305-311
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• 2005

The die development of the high-strength steel sheet has big difference on the formability compared with the general panels. Especially, the springback after stamping of the high-strength steel sheets shows big problem. In this study, for the die development of the high-strength steel sheets, write about examples reducing the lead time and the expense of the die development after CAD modification with the result of the springback analysis after finding the best design planning as several times stamping analysis.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 1997.10a
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• pp.65-71
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• 1997

Computer simulations and test trials are carried out to get the optimal conditions about the stamping die design of the tailor laser welded automotive door inner. Firstly, the stamping process including gravity deflection, bead calibration, binder wrap, forming and spring back, are analyzed by the computer simulation. The results of simulation shows good correspondance with those of test trial under the same conditions. The variables of parametric study which will be investigated in the simulation and test trials, are determined form the results of the first run. The formability under the various conditions is evaluated, which are the initial postion of blank, blank holding force, corner radius and the shape of drawbead. Finally, well controled sound product without fracture, wrinkling and excessive weldline movement is obtained.

• Transactions of Materials Processing
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• v.26 no.4
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• pp.240-245
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• 2017

Mixed-model production technology is a method of producing multiple products with one production process and production line in order to reduce wasted manpower and adjust to market trends. In other words, mixed-model production is a flexible production system that changes production volume by model according to market demand. This study has developed a progressive laminated stamping die technology to enable flexible production of a motor core consisting of attaching and detaching the Cam on the back of the punch so that two kinds of stator and two kinds of rotor could be produced in one progressive die.

• Transactions of Materials Processing
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• v.9 no.6
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• pp.567-573
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• 2000

An analysis system for evaluating the design of dieface of stamping press dies is developed. The die design analysis system interfaced with CATIA via universal or NASTRAN data format provides the design information such as binder-wrap, punch contact status, section length change ratio, wrinkle symptom etc., which are crucial in predicting the defects of initial shape of the sheet in the dieface design stage. The graphic post-processor of developed system which displays 3-dimensional shapes of tool and die and analysis results, helps the interpretation of design evaluation. The dieface design analysis system was tested in draw dies of front floor panel and quarter panel of auto-body in order to verify the usefulness and validity of the system The examples show that the developed system would be a good tool in evaluating dieface designs.

• Transactions of Materials Processing
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• v.7 no.4
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• pp.382-392
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• 1998

Computer simulations and test trials were carried out to obtain the optimal stamping conditions of the die design of the laser welded automotive body. The stamping process including gravity deflection bead calibration binder wrap, forming and spring back was simulated and compared with the results obtained from test trials. The production variables were determined from a preliminary operation and they were investigated in the simulation and the test trials. The formability was tested under the various conditions, such as the initial position of blank, blank holding force, corner radius and the shape of drawbead. Sound products without fracture, wrinkling and excessive weldline movement were produced by applying results obtained this investigation.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 1998.06a
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• pp.102-109
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• 1998

In this study, the side panels were developed using the laser-welded Tailored Blanks (TB) with both the same thickness and the different thickness. At first, the formability of the same thickness T.B was investigated to be compared with one of the non welded panel with respect to weldline movements and strain distribution on blank during the stamping. Based on these results, we selected candidates of T.B with different thickness for stamping experiments. That is, we determined the weld line positions and the die step. Then we made some stamping tryouts with selected types of blank designs to investigate the formability of T.B with different thickness. During the tryouts, the wrinkles were found in the a-pillar lower region which is under the deformation mode of the shrink flange. In the b-pillar region, the fractures were found also, these defects have been reduced and corrected by controlling the blank design and the die faces and process pamameters.

• 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 the Korean Society of Automotive Engineers
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• v.16 no.6
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• pp.10-18
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• 2008

Metal stamping is widely used in the mass-production process of the automobile industry. During the stamping process, air may be trapped between the draw die and the panel. The high pressure of trapped air induces imperfections on the panel surface and creates a situation where an extremely high tonnage of punch is required. To prevent these problems, many air ventilation holes are drilled through the draw die and the punch. The present work has developed a simplified mathematical formulation for computing the pressure of the air pocket based on the ideal gas law and isentropic relation. The pressure of the air pocket was compared to the results by the commercial CFD code, Fluent, and experiments. The present work also used the Bisection method to calculate the optimum cross-sectional area of the air ventilation holes, which did not make the pressure of the air pocket exceed the prescribed maximum value.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2000.11a
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• pp.559-562
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• 2000

Bending is one of the most common cold-stamping operations, recently it is many used to produce structural frame. Depending on the shape and dimensions of complex structural frame, a successive bending operation with simple dies may be economic. But, in this paper, it has been focused to reduce the bending operations by a successive-action compound die. Designed compound-die consists of blank-holder, cam, wedge and etc. In the result, this compound-die for structural frame enabled that it makes seven bending processes into one process, and improved productivity.