• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2005.05a
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• pp.174-179
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• 2005

In the super slow speed die casting process, the casting defects due to melt flow should be controlled in order to obtain sound casting products. The casting defects that are caused by molten metal were cold shut formation, entrapment of air, gas, and inclusion. But the control of casting defects has been based on the experience of the foundry engineers. The calculation of simulation can produce very useful and important results. The calculation data of die casting process condition from the computer simulation by the Z-CAST is made to insure that the liquid metal is injected at the right velocity range and that the filling time is small enough to prevent premature solidification. The parameters of runner shape that affected on the optimized conditions that was calculated with simple equation were investigated. These die casting process control techniques of automobile valve body mid-plate have achieved good agreement with the experimental data of tensile strength, hardness test, and material structure photographies satisfactory results.

• Journal of the Korean Society for Precision Engineering
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• v.17 no.10
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• pp.141-146
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• 2000

We introduce the algorithms of 3-D position estimation using a laser sensor for automatic die remodeling. First, a vision sensor based on the optical triangulation was used to collect the range data of die surface. Second, line vector equations were constructed by the measured range data, and an analytic algorithm was proposed for recognizing the die location with these vector equations. This algorithm could make the transformation matrix without any specific corresponding points. To ascertain this algorithm, folded SUS plate was measured by the laser vision sensor attached to a 3-axis cartesian manipulator and the transformation matrix was calculated.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.2
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• pp.588-593
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• 2011

For the progressive notching and forming die, analyzing beforehand according to the interpretation of thin plate molding for massive production is essential. In this study, we dealt with Ez5 particularly its strip layout design based on the exported die as ordered by Japanese S automobile company's local factory in the USA. We completed the strip layout design consisting of 13 processes by optimizing the blank layout with arrays of a single carrier with wide width drawn in 1 row. This type of die is expected to be ordered in bulk frequently and at the same time via the Internet; any company with die technology will be required to cope with such type of die.

• Journal of the Korean Society for Heat Treatment
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• v.13 no.2
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• pp.71-84
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• 2000

A study on adhesion and wear resistance of VC(vanadium carbide) coating on die steels, STD11 and STD61, has been carried out. The VC coating on the die steels was made by immersing them in molten borax bath, a kind of TRD(thermo-reactive deposition and diffusion). Adhesion strength and wear resistance were investigated using scratch test, indentation test and plate-disc test(Ogoshi type) respectively. The influence of sliding distance on the amount of wear has been determined and dominant wear mechanisms has been characterized using optical microscopy, scanning electron microscopy and EDS spectroscopy. The critical adhesion strength($L_c$) between VC coating layer and substrate(STD11) was increased to 60N($L_c$) in the scratch test. In the case of STD61, the strength increased to 24N. The wear resistance of VC coated die steels was excellent because the diffusion layer formed just below the coating layer. The dominant wear mechanism was identified as adhesive wear for VC coating die steels which were worn by combination of cracking and plucking of VC fragments and disc.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.9
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• pp.4111-4116
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• 2013

The progressive die producing continuously while transferring in order a multiple process is processing law that it is efficient and quality is excellent. In this study the position of precision secured that it occurred when be welded exhaust efficiency of gas boiler combustion exhaust pipe and the exhaust pipe which is cause of incomplete combustion for the purpose of productivity increase. it add burring to a product form and progressive die make die don't disassemble and it be able to exchange burring punch the position of precision and productivity by progressive die is able to improve.

• Journal of the Korean Society for Heat Treatment
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• v.34 no.4
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• pp.185-190
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• 2021

The extrusion experiments using the 7075 aluminum billet have been performed to investigate the effects of die cooling and ram speed on the occurrence of surface defects on the extrudate. The purpose of die cooling was to suppress overheating of the extrudate at the moment of extrusion. In the present die cooling system, liquid nitrogen has been injected in to the die and sprayed to the surface of extrudate. Ram speed was either kept or varied in the range of 1.1~1.7 mm/sec. throughout one extrusion shot to check the occurrence of surface defects. Every extrusion started at a ram speed of 1.25 mm/sec. The temperature of extrudate was measured using a laser thermometer. The 7075 billet of 180 mm in diameter and 550 mm in length was preheated at 390℃ and extruded to get a single plate of 8000 mm in length, 150 mm in width and 10 mm in thickness. Each extrudate was checked by eye to find the surface defects. The microstructures were obtained in the specimen cut from each corner of the extrudate using the EBSD micrographs.

• Design & Manufacturing
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• v.7 no.1
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• pp.40-44
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• 2013

My company develops, manufactures injection mold and produces thin-walled cosmetics and food containers. Without high quality and low production cost, it is hard to compete in the market. To be competitive, a company has to utilize mold with as many cavities as possible to lower manufacturing cost. Eject plate abrasion and deformation cut down mold lifespan, troubles during injection lower productivity and foreign substances in molds cause abrasion. This study focuses on how to improve mold life and productivity, and to slow down mold abrasion.

• International Journal of Automotive Technology
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• v.6 no.2
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• pp.191-196
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• 2005

A full-bead of multi-layer-steel (MLS) engine head gasket is used to seal the combustion gas. Finite element analyses were conducted to assess the dependence of the sealing performance of full-bead on the forming process consisting of embossing and flatting operations. It is demonstrated that the sealing performance is enhanced with more severe deformation of the bead plate during the embossing, i.e., with the increase in the punching depth, the punch height, the punch width and the friction coefficient of the bead plate against the punch and die, and with the decrease in the width of die cavity. Meanwhile, the flatting process that is employed to adjust the height of the embossed full-bead has no influence on the sealing performance.

• Design & Manufacturing
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• v.2 no.5
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• pp.1-4
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• 2008

LCD-BLU (Liquid Crystal Display - Back Light Unit) is one of kernel parts of LCD unit and it consists of several optical sheets(such as prism, diffuser and protector sheets), LCP (Light Guide Plate), light source (CCFL or LED) and mold frame. The LGP of LCD-BLU is usually manufactured by forming numerous dots with $50-200{\mu}m$ in diameter on it by erosion method. But the surface of the erosion dots of LGP is very rough due to the characteristics of the erosion process during the mold fabrication, so that its light loss is high along with the dispersion of light into the surface. Accordingly, there is a limit in raising the luminance of LCD-BLU. Especially, the negative and positive micro-lens pattern fabricated by modified LiGA with thermal reflow process was applied to the optical design of LGP.

• Design & Manufacturing
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• v.6 no.2
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• pp.48-53
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• 2012

In previous study, it showed that the MAP was greatly effective polishing process for magnesium plate. But it had lower efficiency than magnetic materials such as SM45C. It was very difficult to cut non-magnetic materials using the MAP process because the process was fundamentally possible by help of a magnetic force. This study aimed to verify analytically formation of the magnetic field in a case of the non-magnetic materials especially focused on magnesium plate. So, In this study, the magnetic density flux was predicted using simulation program. As a result, the magnetic density flux was lower at the center of pole on inductor than outside. It had same result on the experimental verification. And magnetic force was lower according to increase of working gap. So, to improve the magnetic force, permanent magnet was installed under the workpiece. In that case, the magnetic density flux not only at center but also at outside of pole was increased. Therefore, the efficiency of magnetic abrasive polishing was also increased. A design of experimental method was adopted for assessment of parameters' effect on the MAP results of magnesium plate for improving the magnetic force.