• Transactions of the Korean Society of Machine Tool Engineers
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• v.16 no.4
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• pp.58-63
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• 2007

A compact gun drill machine was developed to improve productivity and economical efficiency for small and medium enterprise tool makers. Gun drilling works are mainly using at molding, automobile, aircraft industry and special tool makers to make deep holes. As gun drill machines are very expensive and big burden for small tool makers, so that works used to execute through outside orders but it was required lot of cost too. Most of gun drill machines are providing for high volume and large capacity enterprises. In order to use for small and medium enterprises that compact gun drill machine was designed and developed. It could be improved product quality, productivity and manufacturing cost for small and medium enterprises by using this machine.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2006.06a
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• pp.40-44
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• 2006

Sandwich structures, which are composed of a thick core between two faces, are commonly used in many engineering applications because they combine high stiffness and strength with low weight. Accordingly, the usage of sandwich structure is very widely applied to the aircraft, the automobile and marine industry, etc., because of these advantages. In this paper, we have investigated the buckling protection of an inner structure plate and the useful corrugated configuration for contact, and the fabrication method of the inner structure plate for large area using the continuous molding process. Also, we have guaranteed the accuracy of the molding process through the micro corrugated mold fabrication and secured the accuracy and analyzed aspect properties of the inner structure plate fabricated for a large area using the partial mold process.

• Proceedings of the KWS Conference
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• 2003.11a
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• pp.162-164
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• 2003

Spot welding, a kind of electric resistance welding, has been used in many fields such as automobile, aircraft, and appliance industry. This paper is to investigate the relationship between tensile shear strength and indentation depth under various welding conditions. The tensile shear strength increases with increasing the welding current in the range of 6-l3kA. The optimum welding conditions were 200∼250kg welding force and 10∼15 cycles welding time at 9kA welding current for EZNCEN. The indentation depth for optimum welding condition was 0.6mm at 9kA welding curent and 200kg welding force, 0.17mm at 9kA welding current and 300kg welding force, 0.19mm at 9kA welding current and 10cycle, 0.17mm at 9kA welding current and 15cycle welding time, respectively.

• Journal of the Korean Society of Safety
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• v.15 no.4
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• pp.15-19
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• 2000

The exact estimation of the ductile crack growth in a thin sheet would be needed in part of the commercial transport aircraft industry fields. A 2-dimensional elastic plastic finite element analysis was carried out to simulate a stable crack extension in a thin sheet 2024 aluminium alloy. Two kinds of crack modeling were used to evaluate curves of the stable crack extension. And then CTOA(crack tip opening angle) and CTED(crack tip energy density) were calculated in order to determine whether they can be used as useful crack extension criterions in a thin sheet. Results indicate that stable crack extension behaviors were simulated well and CTED is more admirable even though CTOA also is reasonable as a criterion for a stable crack extension in a thin 2024 aluminium alloy sheet.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.3 no.4
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• pp.37-42
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• 2004

End-milling have been widely used in aircraft, automobile part and moulding industry. However, various working factors such as spindle speed, feed rate and depth of cut in end-milling have an effect on spindle vibration. There it is demanded the quantitative analysis of spindle vibration in order to get the optimum surface roughness. This study was carried out to analyze an influence of working factors on spindle vibration by design of Experiment. The results are shown that mathematical model of regression equation for an influence of working factors on vibration acceleration of spindle in end-milling by regression analysis is presented.

• Proceedings of the KSME Conference
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• 2008.11a
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• pp.239-243
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• 2008

Nonferrous metals have a very important position in industry. At present, parts of shipbuilding, automobile, and aircraft etc. are designed and manufactured accurately, simultaneity need light-weight and high-strength. Aluminum copper alloys are one kind of typical precipitation hardening alloy which has been widely used. It is interesting to investigate transformation behavior of precipitated phase in such kind of alloys under high magnetic field. Transformation of materials under high magnetic field is many different compared with conventional condition. The author prepared the Al-4%Cu alloy.

• 한국전산유체공학회:학술대회논문집
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• 1998.05a
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• pp.82-89
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• 1998

There are many moving-body problems to be solved, the solution of which necessary for proper design of flight vehicles in aerospace industry. Since a body moves relative to other bodies in the category of these problems, difficulty arises regarding both generation of computational grid around the body in motion and conservation of flow properties in the moving grid system. A few example could be store separation from the aircraft and relative vibration of multiple bodies in the high-speed flow passage. In this paper we report on the progress made in computing moving-body aerodynamics related with sabot separation characteristics. Conservative overlapping grid together with cell-merging-unmerging technique is used to solve the Euler equations for a body in high-speed motion. Carbuncle errors has to be removed before we obtain physically adequate solution. Two-dimensional application is reported here.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.17 no.4
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• pp.47-54
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• 2018

These days, the aerospace industry uses larger machining parts and assembly parts than those in the past. The assembly machines also show the same trend. This study is concerned with the alignment measuring apparatus for the B-axis of a separated multi-axis machine. The alignment measuring apparatus is widely installed for assembly machines in the aircraft assembly process. The alignment measuring apparatus consists of a swivel part and a measuring part. This is a new conceptual idea under patent. All elements of the alignment measuring apparatus are analyzed with the FEM. The analyzed result shows that the alignment measuring apparatus is high in accuracy with stability and steady deformation.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2011.10a
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• pp.558-567
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• 2011

One of the main objectives of noise control act is to define and ensure application and respect of noise exposure limits. Most advanced countries have prepared a legal framework for noise limits either by national laws, ordinances or municipal by-laws. A large number of advaced countries have adopted the $L_{eq}$ index for the main sources of noise (road, railway, industry). The exception is aircraft noise for which regulatory practice is highly disparate. These differences in the indices adopted, the periods and areas to which regulations apply, definitions of measurement conditions and ways in which noise levels are calculated make it difficult to compare the current advanced countries standards. This study presents the current noise abatement policy of the advanced countries and proposes the improvement of the current noise abatement policy of Korea to catch up with it of the advanced countries.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.21 no.6
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• pp.871-877
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• 2012

New materials widely used for automobile related industry, aircraft, space development area are mostly high hardness materials. The hardness value of some hardened materials is over HRC45 and machining of this hardened materials is called as hard turning. Hard turning has its advantage on processing flexibility, cycle time and tool cost reduction. Also this process obtains high efficiency in processing and precise surface roughness through application of the CBN tools. In hard turning process with CBN tool, surface integrity is the important factor for considering the design of machine part and component under high stress and load conditions. A purpose of this study is to analyze optimal condition in hard turning process of AISI 52100 steel (HRC62) with high CBN and low CBN on turning characteristics, tool wear mechanism comparison and surface integrity.