• Journal of Korean Society of Industrial and Systems Engineering
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• v.42 no.1
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• pp.1-7
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• 2019

In the modern industrial period, the introduction of mass production was most important progress in civilization. Die-casting process is one of main methods for mass production in the modern industry. The aluminum die-casting in the mold filling process is very complicated where flow momentum is the high velocity of the liquid metal. Actually, it is almost impossible in complex parts exactly to figure the mold filling performance out with the experimental knowledge. The aluminum die-castings are important processes in the automotive industry to produce the lightweight automobile bodies. Due to this condition, the simulation is going to be more critical role in the design procedure. Simulation can give the best solution of a casting system and also enhance the casting quality. The cost and time savings of the casting layout design are the most advantage of Computer Aided Engineering (CAE). Generally, the relations of casting conditions such as injection system, gate system, and cooling system should be considered when designing the casting layout. Due to the various relative matters of the above conditions, product defects such as defect extent and location are significantly difference. In this research by using the simulation software (AnyCasting), CAE simulation was conducted with three layout designs to find out the best alternative for the casting layout design of an automotive Oil Pan_BJ3E. In order to apply the simulation results into the production die-casting mold, they were analyzed and compared carefully. Internal porosities which are caused by air entrapments during the filling process were predicted and also the results of three models were compared with the modifications of the gate system and overflows. Internal porosities which are occurred during the solidification process are predicted with the solidification analysis. And also the results of the modified gate system are compared.

• Design & Manufacturing
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• v.17 no.4
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• pp.14-23
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• 2023

The electric vehicle market is developing rapidly around the world. Also, parts of electric vehicles require precision.In order to produce high-precision motor cores,Press equipment must also have good precision. Drive motor cores are an important technology for electric vehicles. It uses a large high-speed press to mass-produce drive motor cores. Because it's a large high-speed press, there are many reasons why the precision is not good. One of the causes is vibration and noise. Recently, as environmental demands have become stricter, regulations on noise and vibration have been strengthened. It is important for press machines to reduce vibration first for sound insulation and dust proofing. This is because the "breakthrough" phenomenon occurs in the press. Dynamic precision is the precision under the load of the press, Design considering strain and stiffness shall be made. Vibration and noise may occur due to SPM of high-speed press,And vibration and noise can cause structural deformation of the press. Structural deformation of the press can affect the precision of the product.Noise and vibration also cause problems for workers and work environments. Problems with vibration and noise occur during press processing, and vibration and noise lead to damage to the mold or defects in the product. Reliability in high-quality technology must be secured with low noise and low vibration during press processing. Modular shape and deformation energy effects were analyzed through finite element analysis. In this study, a study on vibration and noise countermeasures was conducted through finite element analysis of a large high-speed press.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.30 no.12
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• pp.751-756
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• 2017

A molding-type power inductor is an inductor that uses a hybrid material that is prepared by mixing a ferrite metal powder coated with an insulating layer and an epoxy resin, which is injected into a coil-embedded mold and heated and cured. The fabrication of molding-type inductors requires various techniques such as for coil formation and insertion, improving the magnetic properties of soft magnetic metal powder, coating an insulating film on the magnetic powder surface, and increasing the packing density by well dispersing the powder in the epoxy resin. Among these aspects, researches on additives that can disperse the metal soft magnetic powder having the greatest performance in the epoxy resin with high charge have not been reported yet. In this study, we investigated the effect of silanes, KBM-303 and KBM-403, and a commercial dispersant on the dispersion of metal soft magnetic powders in epoxy resin. The sedimentation height and viscosity were measured, and it was confirmed that the silane KBM-303 was suitable for dispersion. For this silane, the packing density was as high as about 72.49%. Moreover, when 1.2 wt% of dispersant BYK-103 was added, the packing density was about 80.5%.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.35 no.9
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• pp.1035-1040
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• 2011

This research was performed on a microfilter made of a hybrid material (ceramic + metal) that was coated with ceramics on the metal-filter surface by using the thermal spray method. The ceramic powders used were $Al_2O_3+40TiO_2$ powder with a particle size of $20{\mu}m$ and $Al_2O_3$ (98%+)powder with a particle size of $45{\mu}m$. The metal filters were filter-grade $20{\mu}m$, $30{\mu}m$, and $50{\mu}m$ sintered metal powder filters (SIKA-R 20 IS, 30 IS, 50 IS; Sinter Metals Filters) and filter-grade $75{\mu}m$ sintered mesh filter with five layers. Ceramic-coated filters that were coated using the thermal spray method had a great influence on powder material, particle size, and coating thickness. However, these filters showed a fine performance when used as micro-filters.

• Design & Manufacturing
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• v.17 no.3
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• pp.55-60
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• 2023

The fiber-reinforced plastics and cellular injection molding process can be used to efficiently reduce the weight of battery housing components of mild hybrid electronic vehicles(MHEV) made of metal. However, the fiber orientation of fiber-reinforced plastics and the growth of foaming cells are intertwined during the injection molding process, so it is difficult to predict the mechanical properties of products in the design process. Therefore, it is necessary to evaluate the mechanical properties of the materials prior to the efficient stiffness design of the target product. In this study, a study was conducted to evaluated the mechanical properties of fiber reinforced cellular injection-molded specimens. Two types of fiber-reinforced plastics that can be used in the target product were evaluated for changes in tensile properties of cellular injection-molded specimens depending on the foaming ratio and position from the injection gate. The PP and PA66 specimens showed a decrease of tensile modulus and strength of approximately 30% and 17% depending on the foaming ratio, respectively. Also, the tensile strength decreased approximately 26% and 17% depending on the position from the injection gate, respectively. As a result, it was confirmed that the PP specimens have a significantly mechanical property degradation compared to the PA66 specimens depending on the foaming ratio and position.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.6
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• pp.692-696
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• 2017

The shape of press components is becoming increasingly complex due to customer demands, process shortening and cost savings. In addition, the stability of the pressing process frequently varies during mass production due to the influence of many factors. In order to ensure the process stability, it is necessary to establish a process in which reproducibility is realized in tolerance, which is sufficient for advance study of shape, material, press, mold and lubrication. However, unforeseen changes in process parameters cause disruptions in production line shutdowns and production planning. In this paper, we introduce a method to monitor a real time process by applying a sensor to a press mold. A non-contact type sensor for measuring the flow of a sheet material and an example of an experiment using the optical sensor which is highly applicable to mass production are presented. An optical sensor was installed in a cylindrical drawing mold to test its potential application while changing the material, blank holder force, and drawing ratio. We also quantitatively determined that the flow of other sheet materials was quantified locally using a square drawing die and that the measured value was always smaller than the drawing depth due to the material elongation. Finally, we propose a field that can be used by attaching the sensor to the press mold. We hope that the consequent cost reduction will contribute to increasing global mold competitiveness.

• The Journal of Advanced Prosthodontics
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• v.1 no.3
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• pp.129-135
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• 2009

STATEMENT OF PROBLEM. Zirconia-based restorations have the common technical complication of delamination, or porcelain chipping, from the zirconia core. Thus the shear bond strength between the zirconia core and the veneering porcelain requires investigation in order to facilitate the material's clinical use. PURPOSE. The purpose of this study was to evaluate the bonding strength of the porcelain veneer to the zirconia core and to other various metal alloys (high noble metal alloy and base metal alloy). MATERIAL AND METHODS. 15 rectangular ($4\times4\times9mm$) specimens each of zirconia (Cercon), base metal alloy (Tillite), high noble metal alloy (Degudent H) were fabricated for the shear bond strength test. The veneering porcelain recommended by the manufacturer for each type of material was fired to the core in thickness of 3mm. After firing, the specimens were embedded in the PTFE mold, placed on a mounting jig, and subjected to shear force in a universal testing machine. Load was applied at a crosshead speed of 0.5mm/min until fracture. The average shear strength (MPa) was analyzed with the oneway ANOVA and the Tukey's test ($\alpha$= .05). The fractured specimens were examined using SEM and EDX to determine the failure pattern. RESULTS. The mean shear strength ($\pm\;SD$) in MPa was 25.43 ($\pm\;3.12$) in the zirconia group, 35.87 ($\pm\;4.23$) in the base metal group, 38.00 ($\pm\;5.23$) in the high noble metal group. The ANOVA showed a significant difference among groups, and the Tukey' s test presented a significant difference between the zirconia group and the metal group. Microscopic examination showed that the failure primarily occurred near the interface with the residual veneering porcelain remaining on the core. CONCLUSION. There was a significant difference between the metal ceramic and zirconia ceramic group in shear bond strength. There was no significant difference between the base metal alloy and the high noble metal alloy.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.413-413
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• 2014

In this paper, we present a fabrication method of functionalized gold nanostructures on flexible substrate that can be implemented for plasmonic sensing application. For biomolecular sensing, many researchers exploit unconventional lithography method like nanoimprint lithography (NIP), contact transfer lithography, soft lithography, colloidal transfer printing due to its usability and easy to functionalization. In particular, nanoimprint and contact transfer lithography need to have anti-adhesion layer for distinctive metallic properties on the flexible substrates. However, when metallic thin film was deposited on the anti-adhesion layer coated substrates, we discover much aggravation of the mold by repetitive use. Thus it would be impossible to get a high quality of metal nanostructure on the transferred substrate for developing flexible electronics based transfer printing. Here we demonstrate a method for nano-pillar mold and transfer the controllable nanoparticle array on the flexible substrates without an anti-adhesion layer. Also functionalization of gold was investigated by the different length of thiol applied for effectively localized surface plasmonic resonance sensing. First, a focused ion beam (FIB) and ICP-RIE are used to fabricate the nanoscale pillar array. Then gold metal layer is deposited onto the patterned nanostructure. The metallic 130 nm and 250 nm nanodisk pattern are transferred onto flexible polymer substrate by bi-layer functionalized contact imprinting which can be tunable surface energy interfaces. Different thiol reagents such as Thioglycolic acid (98%), 3-Mercaptopropionic acid (99%), 11-Mercaptoundecanoic acid (95%) and 16-Mercaptohexadecanoic acid (90%) are used. Overcoming the repeatedly usage of the anti-adhesion layer mold which has less uniformity and not washable interface, contact printing method using bi-layer gold array are not only expedient access to fabrication but also have distinctive properties including anti-adhesion layer free, functionalized bottom of the gold nano disk, repeatedly replicate the pattern on the flexible substrate. As a result we demonstrate the feasibility of flexible plasmonic sensing interface and anticipate that the method can be extended to variable application including the portable bio sensor via mass production of stable nanostructure array and other nanophotonic application.

• Composites Research
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• v.15 no.1
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• pp.32-40
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• 2002

This study developed fabrication process of $SiC_p/Al$ metal matrix composites as electronic packaging materials by squeeze casting method. The $SiC_p$ preform were fabricated in newly designed preform mold using about 0.8 % of inorganic binder(SiO$_2$) and 5 vol.% of $Al_2O_3$fiber. To infiltrate the molten metal into the preform, fabrication condition such as the temperature and the pressure were selected. Applying the fabrication conditions, heat transfer analysis were preformed using finite element method and thus analyzed the temperature distribution and cooling characteristic during the squeeze casting. For the fabricated composites, impact toughness and thermal expansion coefficient were measured. The metal matrix composites developed in this study have 0.2~0.3 J impact toughness, $8~10 ppm/^{\circ}C$ thermal expansion coefficient and $2.9~3.0g/cm^3$density which is appropriate properties for electronic packaging application.

• Journal of Korean Society for Atmospheric Environment
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• v.16 no.1
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• pp.23-35
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• 2000

PM10, which is below 10 ${\mu}{\textrm}{m}$ in a diameter, has a high deposition in the lung or the bronchus by breathing and is generally composed of a lot of organic matters, viruses, algae, mold, and metallic elements that are very toxic to people. This study identified the characteristics of concentration of PM10 and air-borne jmetallic elements produced in the industrial city, Ulsan, and analyzed the correlatuion between sources and generation patterns of PM10 and metallic elements. We classified the five areas(green, residential, heavy traffic, mechanic, and petrochemcal and non-ferrous metal) which might have different characteristics of sources of PM10 and metallic elements. The average concentrations of PM10 in the five areas were as follows(petrochemical and non-ferrous metal(99.9$\mu\textrm{g}$/㎥)>mechanic(77.5 $\mu\textrm{g}$/㎥)>heavy traffic(47.1 $\mu\textrm{g}$/㎥)>residential(39.3 $\mu\textrm{g}$/㎥)>green(32.8 $\mu\textrm{g}$/㎥)). Those of petrochemical and non-ferrous metal areas were higher than other areas. In this study, the average concentration trend of metallic elements contained in PM10 are shown as follows: Fe>Zn>Pb>Cu>Mn>Cr>As>Cd>Sn>Hg, respectively. The metallic elements identified in PM10 showed the highest concentration in the petrochemical and non-ferrous areas. Metal combinations showed that a high correlation among concentrations of heavy metals were as follows: As, Cd and Fe in the residential area; Zn, Mn, Cu and Pb in the mechanical area; and Zn, Cu, As, Pb in the petrochemical and non-ferrous industrial area.