• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.21 no.5
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• pp.842-847
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• 2012

The Response Surface Method(RSM) is used as optimal design technique of experimental conditions. In Al7075-T0 turning operation, the principle cutting force and the Center-line averaged roughness are measured to optimize machining process. In variation of feed, depth of cut and cutting speed, three cutting parameters are evaluated. The optimal cutting conditions of Al7075-T0 turning are suggested by RSM. As a main result, feed is the dominant cutting parameter in this turning process considering surface roughness and cutting force.

• International Journal of Naval Architecture and Ocean Engineering
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• v.8 no.3
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• pp.228-234
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• 2016

Recent icebreaking ships need to be designed to enhance not only icebreaking capability but also turning ability. For the evaluation of ice resistance induced by an icebreaking hull form, HHI (Hyundai Heavy Industries) has developed the hybrid empirical formulas (Park et al., 2015) by considering the geometrical hull shape features, such as waterline and underwater sections. However, the empirical formulas have inherent limits to the precise estimation of the icebreaking and turning ability because the breaking process and the resulting pattern are ignored. For this reason, numerical calculation in time domain is performed to predict the icebreaking process and pattern. In the simulation, varying crushing stress according to velocity vectors and contact areas between hull and ice is newly introduced. Moreover, the simulation results were verified by comparing them with the model test results for three different bow-first icebreaking models.

• Proceedings of the KSR Conference
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• 2007.05a
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• pp.698-704
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• 2007

Articulated vehicles which have a pivoting joint allowing the vehicle to rotate more easily are difficult to turn the curves because of their long length. In order to review operational safety, turning characteristics related to geometric design should be investigated when articulated vehicles run on the road which can be interfered with other vehicles. The vehicles to review the turning characteristics are the normal articulated bus in Seoul with FWS(front wheel steering) and new bimodal tram with AWS(all wheel steering). Steering characteristics and geometric design were investigated such as turning radius, offtracking, swept path width and swingout. The results were reviewed with respect to the standards of vehicle safety and road design.

• International Journal of Precision Engineering and Manufacturing
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• v.3 no.1
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• pp.76-82
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• 2002

This paper presents an experimental study of the effect of cutting tool materials on surface quality when turning hardened steels. Machining tests on a lathe are performed using polycrystalline cubic boron nitride (PCBN) and ceramic tools at various cutting conditions without coolant. From the experiments, it is observed that the radial force is the largest force component regardless the type of tool used. The specific cutting energy for the hard turning is estimated to be considerably smaller than the specific grinding energy. It is also found that cutting force and surface roughness with the PCBN tools are higher and better than those with the ceramic tools under the same cutting condition. It is due that the PCBN tools transfer the generated heat more effectively than the ceramic tools due to their higher thermal conductivity. The optimal cutting conditions for the best surface quality are selected by using an orthogonal array concept.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2004.10a
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• pp.28-33
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• 2004

At present, industry and researchers are looking for ways to reduce the use of lubricants because of ecological and economical reasons. Therefore, metal cutting is to move toward dry cutting or semi-dry cutting. This paper presents an investigation into MQL(Minimum Quantity Lubrication) machining with the objective of deriving the optimum cutting conditions for the turning process of SM45C. To reach these goals several finish turning experiments were carried out, varying cutting speed, feed rate and oil quantity, with MQL. The surface roughness results of tests were measured and the effects of cutting conditions were analyzed by the method of Analysis of Variance(ANOVA). From the experimental results and ANOVA, it is found that a better surface roughness can be obtained by decreasing oil quantity and feed rate.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.19 no.2
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• pp.295-300
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• 2010

Inconel 718 alloy, widely used as material of aircraft engine, has a good mechanical property in high temperature, strong anti-oxidation characteristics in oxidated current over $900^{\circ}C$, and also is not easily digested in the air containing sulfur, therefore, its usage as mechanical component is expanding rapidly. Even though Inconel alloy 718 is difficult to machine, it requires highly precise processing/machining to sustain its component quality of high accuracy. In this paper, general turning operation conditions arc tested to select the best cutting process condition by measuring surface roughness through implementing experiments with orthogonal array of cutting speed, feeding speed and cutting depth as processing parameters based on the Taguchi method. Optimal turning operation conditions are extracted from the proposed experimental models.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.11 no.4
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• pp.67-71
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• 2012

The purpose of this study is to investigate cutting characteristics and wear behavior in FCD500 ductile cast iron turning with different cutting tools, tungsten-carbide and CBN. Mechanical property, cutting characteristics and the application to the real industrial area is the final purpose. FDC500 ductile cast iron is now widely used in the various commercial vehicle parts for increased machine abilities which accrue more tensile strength with lower hardness. Several studies have been fulfilled for the material and heat-treatment area, but few with the cutting characteristics and wear behavior in the turning area.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.8 no.4
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• pp.48-53
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• 2009

Inconel 718 alloy, widely used as material of aircraft engine, has a good mechanical property in high temperature, strong anti-oxidation characteristics in oxidated current over $900^{\circ}C$, and also is not easily digested in the air containing sulfur, therefore, its usage as mechanical component is expanding rapidly. Even though Inconel alloy 718 is difficult to machine, it requires highly precise processing/machining to sustain its component quality of high accuracy. In this paper, general turning operation conditions are tested to select the best cutting process condition by measuring surface roughness through implementing experiments with orthogonal array of cutting speed, feeding speed and cutting depth as processing parameters based on the Taguchi method. Optimal turning operation conditions are extracted from the proposed experimental models.

• Journal of the Korean Society for Precision Engineering
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• v.27 no.5
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• pp.14-21
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• 2010

In this study, presintered low purity alumina ceramics were machined with various tools to clarify the effects of the tool material, cutting condition and tool geometry on machinability. The main conclusions obtained were as follows. (a)The wear of tungsten carbide tool becomes smaller with the increase of the feed and clearance angle, and with the decrease of rake angle, especially exhibiting considerably smaller wear with both the decrease of rake angle and the increase of clearance angle. (b) So far as turning the ceramic presintered at low temperature, the diamond tool shows the best performance with higher feed. (c) The effect on the tool wear of the feed, clearance angle and rake angle becomes smaller in turning the ceramic presintered at higher temperature. (d) The tool wear is not severely affected by the depth of cut.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2000.10a
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• pp.460-465
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• 2000

In this study, a durability estimation system of turning centers is developed to systematically evaluate the effects of structural specification and testing condition on the durability. All loads such as weights, inertia forces, cutting force and so on, are automatically transferred from the upper elements to the lower elements by the force flow which can be derived from the structural code of turning center. And the external loads applying to the moving and rolling elements are determined by using the equilibrium conditions of force and moment. Especially, the durability of turning center is estimated based on the lifes of moving and rolling elements under the required testing condition.