• 대한기계학회논문집A
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• 제24권3호
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• pp.752-760
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• 2000

Mechanical press joining has been used in sheet metal joining processes because of its simple process and possibility of joining dissimilar metals, such as steel and aluminum. The strength of mechanical press joining varies with joining conditions. The optimum joining conditions considering tensile-shear and peel-tension strength have to be established to assure the reliability in the joining strength. Therefore, optimization of joining conditions has been investigated for improving joining strength of sheet metal. It is possible to obtain optimum strength from improvement on the joining strength of peel-tension mechanical press joint under multiaxial stress states.

• 대한기계학회논문집A
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• 제33권11호
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• pp.1267-1273
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• 2009

Hot press forming can produce high-strength components by rapidly cooling between closed punch and die after hot forming using quenchable boron steel austenized in a furnace. In the hot press forming process, the cooling rate is influenced by the size, position and arrangement of the cooling channel and the file condition of cooling water in the die. Also, mechanical properties of the final components and operation time are related to cooling rate. Therefore, the design of optimized cooling channel is one of the most important works. In this paper, the effect of position and size of the cooling channel on the cooling rate was investigated by using design of experiment and FE analysis in hot press bending process. Therefore the optimum cooling channel ratio was presented in the HPB.

• 한국생산제조학회지
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• 제5권3호
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• pp.22-30
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• 1996

In order to compensate for out-of-straightness of shafts, an automatic straightening process composed of an automatic measuring module, an automatic control unit and operating softwares was developed with a hydraulic press. The out-of-sraightness of each shaft was measured automatically in the measuring stage. An optimal pressure point was determined to minimize TIR value of the shaft according to press count of 3-points bending process. In the geometric adaptive control procedure, punch stroke and springback of the shaft were predicted by an observer using on-line measured values of press force and deflection amount I each press count. An automatic straightening machine was realized with the measuring module, the GAC module, PLD, IBM-PC and the operating software on the hydraulic press. the validity of the proposed straightening process was confirmed through a series of experiments with cam shafts.

• Design & Manufacturing
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• 제10권3호
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• pp.46-50
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• 2016

Laminate products for motor core are developed with a structure in which the importance of quality level and clamping force is influenced by the recent performance and safety of the product. It has been confirmed that the accuracy of the mold is emphasized, and that the accuracy of the tightening force produced by the stacked product for the motor core is greatly influenced by the change in the bottom dead center displacement of the aged high speed press. The reason why setting the mold, and test the effect of bottom dead center of high speed press is to improve product pull force in embossing process at mold. We have applied the system to minimize the effect on the damping displacement under the dynamical degree of the equipment by applying the emboss complement device which can test the influence and complement in the process.

• 소성∙가공
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• 제23권4호
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• pp.206-210
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• 2014

The metal lead frame, a semiconductor component, has product tolerances in micro units as compared to products made with a larger size mold. Therefore, small deflections of the mold and of the press as well as the press molding process itself have a strong influence on accuracy of the product. Hence, it is necessary for the process design to consider the structural response of the mold and the press during deformation. In the current study, the mold deflection and pressure on the punch is examined using the finite element modeling (FEM) program ABAQUS. The results from the simulation were verified with the dynamic deformation measurement equipment using digital image correlation (DIC).

• 한국정밀공학회지
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• 제27권5호
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• pp.48-55
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• 2010

The Door hinge is a very important part for door sagging performance of a vehicle. It is divided into two classes as a forge- and press-type according to a manufacturing technique. The press-type door hinge is cheap, but shows low strength. To apply the press-type door hinge to a fullsized car with satisfactory door sagging performance, we optimized the design parameters of the door hinge using the DFSS method. As a result, the effective design parameters of the press-type door hinge with good door sagging performance were obtained.

• 소성∙가공
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• 제26권5호
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• pp.277-285
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• 2017

Vehicle weight reduction is a known strategy to improve fuel efficiency and strengthen exhaust gas regulation. The use of high strength steel can satisfy safety, efficiency, emission, manufacturability, durability, and cost requirements. However, springback of high strength steel results in undesired shape defects. Springback is one of the most important issues of high strength steel for many applications in an automobile. Servo press has various capabilities to improve defects, process conditions, and productivity problems when forming a high strength steel. Especially, servo press can be set to function with variable slide motion in a single operation. In this study, the effect of servo press slide motion on 980MPa high strength steel was investigated through U-bending test.

• 한국의류학회지
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• 제20권5호
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• pp.792-800
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• 1996

The shape retention finishing provides a fabric for easiness of no-ironing after laundering. In spite of the obvious importance of the new finishing treatment, few systematic studies have been performed on the handle of the fabrics finished by the durable press process. The purpose of this research is to investigate the relationships among the mechanical properties, durable press conditions, primary hand values and the total hand value of the fabrics finished by shape retention process. In this experiment, durable press grade of unfinished fabrics decreased below 2.5, but those of finished fabrics maintained above 4, but the mechanical properties of finished fabrics did not change significantly after laundering. In finished fabrics, D.P. value were correlated with mechanical properties, but had little effects with H.V. and T.H.V. Since the evaluation of the effect of durable press process was done with the naked eyes and standard sample, we could not know exactly change o( mechanical properties, but trace the change of mechanical properties which gave influences on the durable press effects by using KES-FB System.

• 한국안전학회지
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• 제25권6호
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• pp.40-46
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• 2010

To protect press operator from the after-reach hazard, current Ministry of Labor Notification(MOLN) requires the use of a formula for calculating the safe distance away from the point of operation for locating press protective devices, Two Hand Control Devices(THCD) and Active Opto-Electronic Protective Devices(AOPD), on a power press. This formula is based on a same hand speed constant of 160cm/s. While EN standards use different hand speed constant for THCD and AOPD respectively. The objective of this study is to compare two guidelines on the hand speed constant published by MOLN and EN 692, also to propose a proper hand speed constant and validate it experimentally. As a experimental result, it could be known that hand speed constant of Ministry of Labor Notification should be improved as that of EN standards.

• 한국CDE학회논문집
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• 제14권5호
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• pp.314-322
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• 2009

In these days, automotive companies are trying to develop new manufacturing technologies and paradigms for rapid product development and production. The press die development process account for 40% of entire vehicle development process, and tryout process usually takes 3 to 4 months, and it is the biggest time portion out of dies manufacturing. Therefore, the effective tryout management system is essential to reduce time and cost of automotive press die production. This paper suggests improved process and practical application of tryout management using ubiquitous technology, and shows the results such as shorten time, improved quality and supporting of lifecycle engineering of press die.