• Transactions of the Korean Society of Mechanical Engineers A
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• v.27 no.8
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• pp.1309-1316
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• 2003

The general dicing process cuts a semiconductor wafer to lengthwise and crosswise direction by using a rotating circular diamond blade. But products with inferior quality are produced under the influence of several parameters in dicing process such as blade, wafer, cutting water and cutting conditions. Moreover we can not apply this dicing method to GaN wafer, because the GaN wafer is harder than the other wafer such as SiO2, GaAs, GaAsP, and AlGaAs. In order to overcome this problem, development of a new dicing process and determination of dicing parameters are necessary. This paper describes a new wafer dicing method using fixed diamond scriber and precision servo mechanism and determination of several parameters - scribing depth, scribing force, scriber inclined angle, scribing speed, and factor for scriber replacement - for a new dicing machine using scriber.

• Proceedings of the KIPE Conference
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• 1998.07a
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• pp.352-356
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• 1998

This paper is a study about Ac servo motor position and speed control characteristics which depend on feedforward control, the acceleration / deceleration time constant after the interpolation, and PI control, automatic deceleration at corner in order to shape cutting control of feed drive system of the machine tool. The shape error caused by delay of the servo system in the direction of radius at the time of circular cutting is reduced by feedforward control. The shape error generated by the position command delay is minimized by using the acceleration / deceleration time constant after the interpolation. The results were verified to optical machining center experimentation of the machine tool.

• Journal of the Korean Society for Precision Engineering
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• v.20 no.2
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• pp.218-225
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• 2003

The general dicing process cuts a semiconductor wafer to lengthwise and crosswise direction by using a rotating circular diamond blade. However, inferior goods may be made under the influence of several parameters in dicing process such as blade, wafer, cutting water and cutting conditions. Moreover we can not apply this dicing method to a GaN wafer, because the GaN wafer is harder than other wafers such as SiO$_2$, GaAs, GaAsP, and AlGaAs. In order to overcome this problem, development of a new dicing process and determination of dicing parameters are necessary. This paper describes determination of several parameters - scribing depth, scribing force, scriber inclined angle, scribing speed, and factor for scriber replacement - for a new dicing machine using a scriber.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.10a
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• pp.210-213
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• 2002

The Purpose of this study is to know temperature and thermal stress distribution in specimens during processing of WEDM. If it is constant to the cutting speed and the thickness of material, it is very important to the effect of temperature and the thermal stress distribution after cutting processing. This paper show the analysis result of the distribution of temperature and the residual stress along the direction of thickness before processing of WEDM and after when the cooling temperature is$20^{\circ}C$. The maximum temperature of edge of specimens is $1600^{\circ}C$. It has little temperature gradient in the depth which is 5mm away from edge of specimens. Equivalent residual stress is result in 180.7 MPa at maximum temperature.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.10a
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• pp.164-167
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• 2002

The general dicing process cuts a semiconductor wafer to lengthwise and crosswise direction by using a rotating circular diamond blade. But inferior goods are made under the influence of several parameters in dicing process such as blade, wafer, cutting water and cutting conditions. Moreover we can not applicable this dicing method to GaN wafer, because the GaN wafer is harder than the other wafer such as SiO$_2$, GaAs, CaAsP, and AlCaAs. In order to overcome this problem, development of a new dicing process and determination of dicing parameters are necessary. This paper describes determination of several parameters - scribing depth, scribing force, scriber inclined angle, scribing speed, and factor for scriber replacement - for a new dicing machine using scriber.

• Journal of Biosystems Engineering
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• v.19 no.3
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• pp.175-184
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• 1994

This study was conducted to investigate experimentally the basic characteristics of the torque of the cutterbar driving shaft as the double-knife was used instead of the conventional standard single-knife type. A new design for inclined setting of the cutterbar relative to the direction perpendicular to combine harvester movement was investigated to test a possible reduction of concentrated load caused by the simultaneous cutting of many rows. It was evaluated that the maximum torque and mean total power of the driving shaft due to the cutting resistance of the rice straw were largely depended upon the rotational shaft-speed and straw feeding rate, but were resepectively 1.1~2.3 and 1.15~1.34 times higher compared to those while idling. It was also proved that the inclined setting of the cutterbar could save a considerable amount of energy required for its driving shaft.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09b
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• pp.1140-1141
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• 2006

Diamond tools with several layers of diamond grits through thickness direction were tested by sawing. The saw blades with evenly distributed grits showed better cutting performance compared to the random distributed saw. At a given concentration of grits, as the spacing between layers was increased, the cutting performance was improved, and as decreased, it showed more tool life

• Fashion & Textile Research Journal
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• v.2 no.3
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• pp.234-238
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• 2000

In this study it was measured seam strength of T/C which has the different processing methods and density. Also it was measured seam strength by the change of angle in the pattern and the kinds of threads. The results of this study are as follows; The seam strength is stronger in order of $90^{\circ}/90^{\circ}$ > $0^{\circ}/0^{\circ}$ > $70^{\circ}/-70^{\circ}$ > $70^{\circ}/70^{\circ}$ > $60^{\circ}/60^{\circ}$ > $60^{\circ}/-60^{\circ}$ > $30^{\circ}/30^{\circ}$ > $30^{\circ}/-30^{\circ}$ > $45^{\circ}/-45^{\circ}$ > $45^{\circ}/45^{\circ}$ by the cutting directions, in order of T/C3>T/C1>T/C4>T/C2 by the samples and in order of 60's/3>40's/2>60's/2>50's/2 by the threads.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2005.05a
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• pp.168-173
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• 2005

Composite material is combined with two or more chemical ingredient and different components. FRP has been widely used for the structure of aircraft, ships, automobiles, sporting goods and other machines because of their high specific strength, high specific stiffness and excellent fatigue strength. Recently, the development of machine tool and cutting tool greatly relies on high speed process to satisfy high precision, high efficient machining, shortened process time to maximize material removal rate (MRR) through high cutting speed and feed speed. The research molded CFRP, GFRP as stacking sequence methods of two direction (orientation angle $0^{\circ}\;and\;0^{\circ}/9^{\circ}$) hand lay-up, drilled molded plates using cemented carbide drill and examined chip shapes, surface roughness properties.

• Journal of the Korean Society for Precision Engineering
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• v.14 no.8
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• pp.21-28
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• 1997

This paper presents the influence of the process parameters on the change in dynamic behavior of a lathe turning system. With variation of feed rate, depth of cut, direction of tool motion, cutting speed and tool location along the workpiece, the dynamic characteristics of stable cutting, chatter transition and fully developed chatter regions are demonstrated. The workpiece vibration during machining is continuously measured at different tool locations along the workpiece and quantitatively analyzed. Complex linear behavior due to change of process parameter values as well as fundamental wystem nonlinearity due to change of process configuration indicated by a tool path dependence of the locations of chatter onset and disappearance are described. Finally, the structural characteristics of the turning system which can have large and nonlinear effects on system behavior are presented.