• Journal of the Korean Society of Manufacturing Process Engineers
• /
• v.19 no.9
• /
• pp.93-99
• /
• 2020

Recently, as the weight reduction of vehicles has been actively progressed, parts developed using aluminum 60XX series from existing steel materials are increasing. In this paper, the bushing used for the front frame rail, which is one of the parts for fixing engines and other parts in automobiles, was changed to an aluminum material of the Al60XX series, and it was intended to be produced by applying of cold forging method. The bushing is a part that secures the engine frame, and in order to produce it by cold forging, the molding limit is predicted through process design, and a multi-stage process is designed through finite element analysis. In addition, in order to verify the feasibility of the designed forging process, the limits of the multi-step process were verified based on the Cockcroft Latham theory, and the crack and overlap of the actual forging work were predicted and improved.

• Journal of Mechanical Science and Technology
• /
• v.16 no.12
• /
• pp.1687-1692
• /
• 2002

The problem analyzed here is a sheet metal forming process which requires a drawbead. The drawbead provides the sheet metal enough tension to be deformed plastically along the punch face and consequently, ensures a proper shape of final products by fixing the sheet to the die. Therefore, the optimum design of drawbead is indispensable in obtaining the desired formability. A static-explicit finite element analysis is carried out to provide a perspective tool for designing the drawbead. The finite element formulation is constructed from static equilibrium equation and takes into account the boundary condition that involves a proper contact condition. The deformation behavior of sheet material is formulated by the elastic-plastic constitutive equation. The finite element formulation has been solved based on an existing method that is called the static-explicit method. The main features of the static-explicit method are first that there is no convergence problem. Second, the problem of contact and friction is easily solved by application of very small time interval. During the analysis of drawbead processes, the strain distribution and the drawing force on drawbead can be analyzed. And the effects of bead shape and number of beads on sheet forming processes were investigated. The results of the static explicit analysis of drawbead processes show no convergence problem and comparatively accurate results even though severe high geometric and contact-friction nonlinearity. Moreover, the computational results of a static-explicit finite element analysis can supply very valuable information for designing the drawbead process in which the defects of final sheet product can be removed.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2013.02a
• /
• pp.218-218
• /
• 2013

We report a simple and cost-effective method to fabricate transparent superhydrophobic surface on various substrates. The surface was fabricated by coating hydrophobic PDMS (polydimethylsiloxane) film on the silica nanoparticle and subsequent fixing of the hydrophobic silica nanoparticles onto substrates. The water contact angle for the prepared surface was determined to be over $150^{\circ}$, whichindicates that the surface is highly repellent to water. The hierarchical structure and roughness of the surface were examined by scanning electron microscopy (SEM) and atomic force microscopy (AFM). Additionally, transparency of the prepared surface was measured with UV-VIS spectrometer. The transmittance of the superhydrophobic surface was ~80%, which is lower than that without PDMS-coated silica by only 5 to 10%. It is also notable that the superhydrophobic surface fully recovers its original transmittance after self-cleaning process. Also the PDMS coating is stable under a wide range of pH conditions, UV radiation and salinity conditions, which is essential for the practical use. Moreover, our fabrication method is applicable in large scale production.

• Journal of Powder Materials
• /
• v.22 no.2
• /
• pp.134-137
• /
• 2015

The monolayer engineering diamond particles are aligned on the oxygen free Cu plates with electroless Ni plating layer. The mean diamond particle sizes of 15, 23 and $50{\mu}m$ are used as thermal conductivity pathway for fabricating metal/carbon multi-layer composite material systems. Interconnected void structure of irregular shaped diamond particles allow dense electroless Ni plating layer on Cu plate and fixing them with 37-43% Ni thickness of their mean diameter. The thermal conductivity decrease with increasing measurement temperature up to $150^{\circ}C$ in all diamond size conditions. When the diamond particle size is increased from $15{\mu}m$ to $50{\mu}m$ (Max. 304 W/mK at room temperature) tended to increase thermal conductivity, because the volume fraction of diamond is increased inside plating layer.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.14 no.8
• /
• pp.3650-3655
• /
• 2013

A state purpose to produce fine blanking die gets to be the maximum size of share surface the study considered that change a size of share area. the clearance affecting most greatly size of share surface fixing as 1% of material thickness and while change share speed, A distance change from share line to V-ring center, A change of V-ring angle. it designed. Each test specimen taken from the share surface size analysis of the V-ring distance of 2mm, the outer $45^{\circ}$ / inner$30^{\circ}$ if the, Shear speed was found that the area of the entire cross section is largest the 6.4m/min.

• Proceedings of the Korean Geotechical Society Conference
• /
• 2008.03a
• /
• pp.419-426
• /
• 2008

Recently, localized heavy rain due to "EL-LIO" was a kind of reason by risk of slope stability. In this paper, the behaviour of slope when localized heavy rain was studied. In order to perform this study experimental programs were performed. Experimental programs was checked filtering conditions for slope stability due to localized heavy rain. And then, investigated slope stability and fracture mechanism each other types. In the experimental study, performed changing filtering condition by embankment, through five fixing factors such as rainfall intensity, slope shape, geological condition, compaction energy and water content. According to the results of this study, behaviour of facture slope has made a shallow and narrow waterway. This waterway expanded base stone. In order to, suggested a system for slope stability examination.

• Journal of the Korean Institute of Rural Architecture
• /
• v.5 no.3
• /
• pp.1-7
• /
• 2003

This study is to find out the betterment way of cost down in the architectural temporary work. To do so, it is more important to check every case above all and find and choice optimum way fitting a scene of a construction field. In addition, in case that the way to apply in proportion to a given condition is complicated, the way to find out cost down way is to adopt the individual peculiarity instead of the generality. Hereupon this study is rather to find out the better way to reduce such as material and manpower cost than to leave matters not to be settled to get the best way in the existing temporary work. So this study is composed with finding the existing problems, fixing the focus about the developmental way to reduce cost in the exterior and interior temporary work, presenting the new construction way and describing the merits and attentions of an improved exterior and interior temporary work.

• Applied Science and Convergence Technology
• /
• v.24 no.2
• /
• pp.27-32
• /
• 2015

We analyzed the destruction patterns of a turbo-molecular pump (TMP) resulting from its sudden exposure of a foreline to the atmospheric pressure due to a destruction of the foreline connecting clamp of an ICP dry etcher for 300 mm wafers during high-vacuum operation ($5{\times}10^{-6}$ Torr). Unlike in the case of view port's breakage, the TMP's rotor module was crashed inside the chamber. The primary damage resulted from the collision of the blades and stators, and the secondary damage resulted from the breaking of the rotor - driving shaft assembly. The fixing screws of the rotor and axial shaft were bent and broken when the TMP controller output the maximum current even after the crash event. Electrical power consumption analysis of the TMP power controller confirmed it. The stress distributions were analyzed by a finite element method using CFD-ACE+ multi physics software. Rotating inertia of each parts and kinetic energies were calculated as well. 68% of the rotational kinetic energy is deposited by the rotor - shaft module.

• Journal of Korean Society of Industrial and Systems Engineering
• /
• v.30 no.1
• /
• pp.96-104
• /
• 2007

Glass melting process is influenced by both control and observation factors, where control factors include quantity and mixing ratio of raw material, the amount of fuel and air in-take. Further observation factors include temperature and pressure at each step of process inside glass melting furnace. Ambient Control is an effective means to eliminate complications from excessive variation among raw materials, or external disturbance from wide fluctuation of environment around equipments. Ambient Control uses both control and observation factors mentioned above. This study suggests an effective Proactive Control System that can enable genuine 4M standardization in glass melting furnace by applying Ambient Control.

• Proceedings of the Korean Institute of Building Construction Conference
• /
• 2013.05a
• /
• pp.313-314
• /
• 2013

The study carried out the experiment with presenting as the fundamental data for developing non-cement by using red mud generated in blast furnace slag and bauxite generated in the process of manufacturing the pig iron process of manufacturing Al(OH)₃/Al₂O from as the binding material using the accelerator of NaOH. After fixing the thing and the NaOH adding the blast furnace slag and NaOH 10, 20, 30 (%) with 10, 20, 30 (%) substituted the red mud in the blast furnace slag and the experimental method carried out the experiment. And it measured the flexural strength and compressive strength and took a photograph EDS analysis and SEM. Consequently, the compressive strength was improved as the addition rate of the NaOH was high and the compressive strength according to the replacement ratio of the red mud was degraded. This is determined that film of the blast furnace slag is destroyed and it makes the hydration reaction condition and the intensity is revealed.