• Journal of Drive and Control
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• v.19 no.4
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• pp.10-18
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• 2022

Air-drop hammer press and counterblow hammer press are widely used power-drop forging hammersemploying different forging blow mechanisms. It is important and necessary to analyze mechanical vibrations of these two different hammers in their forging processes in order to develop high performance forging hammers. In this study, these two forging hammers were mathematically modelled as mass-spring-damper systems. For these two different types of forging hammers, the forging efficiency and mechanical vibrations due to hammer forging blow were theoretically analyzed and compared. The force transmitted to the ground was also determined and compared. Especially, effects of mass ratio and restitution coefficient on forging efficiency were investigated.

• Resources Recycling
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• v.27 no.5
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• pp.61-68
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• 2018

The aluminum dross is oxide generated on the surface of the molten metal during the aluminum melting process and it is divided into white dross and black dross according to presence of the Salt flux. White dross has high metal content and is recycled via the melting process. Black dross is largely berried, because the it has a low metal content and difficulty in separating the components. Black dross contains a salt components such as NaCl and KCl, and inorganic materials such as $Al_2O_3$ and MgO, and it is necessary to study the technology to recover and recycle such valuable resources. In this study, a process for recycling aluminum black dross was proposed. The inorganic and soluble substances present in the black dross were separated through crushing-dissolution-solid/liquid separation-decompression evaporating. By controlling the ratio of water and black dross, the recovery condition of the separated product was optimized and we confirmed the highest Salt flux recovery efficiency 91 wt.% at black dross:water ratio 1:9. Finally, Through the synthesis of zeolite using recovered ceramic material, the materialization possibility of black dross was confirmed.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.6
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• pp.3363-3369
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• 2014

Recently, considerable effort has been made to maintain a pleasant and safe indoor environment in buildings. For this, the use of a ventilation system attached to a range hood in kitchens has prevailed. Accordingly, diversiform designs for range hoods have been used. Press molding is normally used for range hood construction for several reasons. On the other hand, its economic efficiency is low in the case of a small production work. Considerable research has been carried out to solve this problem and it is believed that it is useful to use the change core method to develop molds. This study designed the core of a mold using the change core method and a total of four processes were used in its manufacture. As a result, the press molds, which are needed for shorter production runs and whose form is changeable, were developed. In addition, after the measurements in three-dimensions, the specimen passed a test within a tolerance of ${\pm}2.00mm$.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.3
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• pp.72-77
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• 2017

This paper focuses on the development of a supporting S/W tool for the automated design of an automotive press trim die. To define the die design process based on automation, we analyze the press die design process of the current industry and group repetitive works in the 3D modeling process. The proposed system consists of two modules, namely the template models of the trim steel parts and UI function for their auto-positioning. Four kinds of template models are developed to adapt to various situations and the rules of the interaction formula which are used for checking and correcting the directions of the datum point, datum curve, datum plane are implemented to eliminate errors. The system was developed using CATIA Knowledgeware, CAA(CATIA SDK) and Visual C++, in order for it to function as a plug-in module of CATIA V5, which is one of the major 3D CAD systems in the manufacturing industry. The developed system was tested by applying it to various panels of current automobiles and the results showed that it reduces the time-cost by 74% compared to the traditional method.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.05a
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• pp.437-438
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• 2006

Generally, the vertical roll process is used to achieve extensive width reduction in hot strip mill. However, it is difficult to avoid the defects such as dog-bone and seam-defect. The sizing press has been developed in response to the defects mentioned above. Especially, this study is carried out to investigate the deformation of slab by two-step sizing press. The deformation behavior in the width sizing process is more favorable than that in conventional vertical rolling edger. The objective of this study is to determine the optimal anvil shape parameters in the sizing press with two-step die from the viewpoint of edge-seam length. In general, the edge-seam defect occurs parallel to the rolling direction at both edges in horizontal rolling process after sizing press. The optimal combination of the parameters is determined by FE-simulation and Artificial Neural Network (ANN). The slab deformation in sizing press with convex anvil is analyzed by FE-simulation. The most suitable profile of the anvil is also discussed fur the improvement of trimming loss because of the side seam defect by FE-simulation and ANN.

• Journal of Adhesion and Interface
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• v.7 no.2
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• pp.26-31
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• 2006

In order to effectively improve interfacial adhesion strength between polypropylene (PP) and jute fiber, we particularly incorporated maleic anhydride grafted PP (MAPP) into the matrix through the environment-friendly process without an additional method of process and had better mechanical performances by providing the alignment into the natural fiber than those of the conventional fabrication technology such as an extrusion or injection molding. We also proposed hot pressing method which applied relatively low shear to the composites and confirmed the chemical bonds among the functional groups of MAPP and jute using FT-IR approach. The concentration of MAPP for maximum tensile strength and modulus was optimized at 3 wt%. Flexural properties had no noticeable tendency to increase with MAPP contents compared to tensile strength, which could probably be explained by the degree in wetting of PP/MAPP matrix.

• Journal of Advanced Marine Engineering and Technology
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• v.35 no.8
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• pp.1048-1054
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• 2011

Laser surface hardening process is the method of hardening surface by inducing rapid self quenching of laser injected area through transfer of surface heat to inside after rapid heating of laser injected area only by high density energy heat source. This surface treatment method does not involve virtually any thermal deformation by heat treatment nor accompanies any other process after surface hardening treatment. In addition, allowing local machining, this method is a surface treatment method suitable for die with complicated shape. In this study, die material cast iron was surface-treated by using high power diode laser with beam profile suitable for heat treatment. Since the shapes of die differ by press die process, specimens were heat-treated separately on plane and corner depending on the applied parts. At this time, corner heat treatment was done with optic head inclined at $10^{\circ}$. As a result, corner heat treatment easily involves concentration of heat input due to limitation of heat transfer route by the shapes compared with plane part, so the treatment accomplished hardening at faster conveying speed than plane heat treatment.

• Journal of the Society of Naval Architects of Korea
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• v.38 no.4
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• pp.66-74
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• 2001

Plate bending process is indispensible in shipbuilding. The process includes press bending process and heating process. Especially the heating process is carried out exclusively by skillful workers. Many researches have been made to automate the heating process. This study was carried out as a fundamental study to develop a efficient analysis method for triangle heating and focused on clarifying the deformation characteristics of plate by triangle heating and essential elements effect on the deformation. In this paper, we proposed an analysis model for thermal-elastic-plastic analysis and simulated the deformation by triangle heating using ANSYS based on the experimental results of Jang et al.(2001). Also, we showed the deformation characteristics more clearly by comparing the deformation due to triangle heating and line heating in case that the total heat input is same. Finally, we investigated the change characteristics of deformation elements according to the volumetric heat input.

• Design & Manufacturing
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• v.17 no.1
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• pp.56-63
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• 2023

In this study, the vibration signal of the mold was measured and analyzed to monitor the process information and characteristics during the press molding process. A necklace-type picture frame mold was used for press molding, and the vibration signal was measured by GY-61 acceleration sensor module attached to the surface of the upper (movable) mold base. The change of the vibration signal of the mold according to press speed was analyzed. As a result, the vibration signal had a large change at five sections: "Holder contact", "Punch contact and start of pressing", "End of pressing", "Mold open", and "Demolding". The time difference between "Punch contact and start of pressing" and "End of pressing" means the pressing time which is the actual time the material is molded under pressing pressure. The time intervals for each section, represented by the time interval between "Holder contact" and "Punch contact and start of pressing", can be used to compare and evaluate the press speed applied to the process. By comparing the vibration signals at 60 rpm and 90 rpm, the amplitude at the section of "Punch contact and start of pressing" increased as the press speed increased. This result means that as the press speed increases, more force and pressure is applied to the material. Also, the peak values of the other sections were found to increase as the press speed increased. It was found that the pressing time, the time interval between "Punch contact and start of pressing" and "End of pressing", decreases as the pressing speed increases. Similarly, press speed factor, the time interval between "Holder contact", and "Punch contact and start of pressing", is found to be shorter. Therefore, based on the result of this study, the pressing time, press speed, pressing(punching) pressure of each cycle can be monitored by measuring the vibration signal of the mold. Also, it was confirmed that the level and trend of process information and characterization can be evaluated as the change of the mold vibration during press molding.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.1294-1298
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• 2005

In this study, combined micro press and surface finishing process are proposed to fabricate the micro nozzle array on a stainless steel sheet metal. In micro hole punching process the burr occurs inevitably, but the burr must be minimized in order to improve the quality and accuracy of the product. For this reason, subsequent magnetic field-assisted finishing technique is applied to remove the burr which exists around the nozzles for ink-jet printer head and proved to be a feasible for deburring by experiment. The deburring characteristics of sheet metals were investigated changing with polishing time and magnetic abrasive size. After the deburring, the burr size has remarkably reduced and roundness of the hole also has improved.