• Proceedings of the Korean Society of Precision Engineering Conference
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• 1995.10a
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• pp.48-52
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• 1995

Chipping is an unavidable phenomean in the slot grinding process of hard and brittle materials. However,it should be reduced for the improvement of surface integrity in the manufacture of optical and semiconductor components. Electrolytic In-process Dressing (ELID) technique for metal bonded superabrasive grinding wheel has been developed for mirror surface grinding of hard and brittle materials. Electrically dressed wheel surface has sharply exposed abrasives and results in lower grinding force, higher grinding efficiency in grinding. The paper deals with a newly developed method for slot grinding using ELID and was implemented to improve grooved surface quality and decreases chipping size on the edge of the groove. As a result, we accomplished shipping-free grooves and obtained the clear ground sufaces on glass and tungsten carbide.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.61 no.3
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• pp.433-436
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• 2012

We propose a novel micro surface plasmon resonance (SPR) sensor system based on polymer materials. The proposed SPR system consists of the incident medium with polymer waveguide and the gold thin film for sensing area. Using a polymer optical waveguide instead of a prism in SPR sensing system offers miniaturization, low cost, and potable sensing capability. The whole device performance was analyzed using the finite-difference time domain method. The optimum gold thickness in the attenuated total reflection mirror of polymer waveguide is around 50 nm and the resonance angle to generate surface plasmon wave is 68 degrees.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2000.04a
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• pp.591-596
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• 2000

The needs of ultra precision machined parts is increase every days. But the experimental data of nonferrous metal is insufficient. The cutting behavior in micro cutting area is different from that of traditional cutting because of the size effect. Al6061 is widely used as optical parts such as LASER reflector's mirror or multimedia instrument. Al6061 opper is machined by ultra precision machine with natural diamond tool. From the experiment and discussion on the cutting force and worked surface roughness as the variable spindle speed, feed rate and depth of cut. As a result, the cutting force increases as the increasing depth of cut, but the worked surface roughness does not increase so much. The surface roughness is good when spindle sped is above 1200rpm, and feed rate is small. The influence of depth of cut is very small.

• Journal of the Korean Society for Precision Engineering
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• v.10 no.4
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• pp.128-134
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• 1993

Work roll wear in the cold rolling of mild steel strip is strongly affected by rolling materials, rolling conditions and lubrication. The tests were performed to find the effects of rolling materials under the same lubrication conditions. The obtained results are as follfws; 1) The decrease in surface roughness of work roll is more rapid in that case of continuously cast A1-killed steel strip than ingot cast steel strip. In rolling of continuously cast A1-killed steel strip, worn powder rich in A1$\_$2/O$\_$3/sticks to the work roll surface, and so it makes the mirror surface of work roll accelerate. 2) Amount of work roll wear is small in rolling of continuously cast A1-killed strip. 3) In rolling of continously cast A1-killed steel strip, it is necessary to put up the intial surface roughness of work roll in order to prevent work roll slip.

• Korean Journal of Optics and Photonics
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• v.24 no.6
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• pp.331-337
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• 2013

A large optical surface is fabricated by grinding, polishing and figuring. The grinding process is the most rapid and has the largest amount of fabrication of all processes. If we measure the surface precisely and rapidly in the grinding process, it is possible to improve the efficiency of the fabrication process. Since the surface of grinding process is rough and not shiny, it is not easy to measure the surface using light so that we cannot use an interferometer. Therefore, we have to measure the surface using a mechanical method. We can measure the surface under the grinding process by using a laser tracker which is a portable 3-dimensional coordinate measuring machine. In this paper, we used the laser tracker to measure the surface error of 1 m diameter spherical mirror. This measurement result was compared to that of an interferometer. As a result, surface measurement error was found to be $0.2{\mu}m$ rms (root mean square) and $2.7{\mu}m$ PV (Peak to Valley), which is accurate enough to apply to the rough surface under the grinding stage.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.15-18
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• 2005

As consumer in optics, electronics, aerospace and electronics industry grow, the demand for ultra-precision aspheric surface lens increases higher. To enhance the precision and productivity of ultra precision aspheric surface micro lens, The development of ultra-precision grinding system and manufacturing properties for the aspheric surface micro lens are described. In the work reported in this paper, and ultra-precision grinding system for manufacturing the aspheric surface micro lens was developed by considering the factors affecting the surface roughness and profiles accuracy. And this paper deals with mirror grinding of an aspheric surface micro lens by resin bonded diamond wheel and spherical lens of BK7. It results was that a form accuracy of $3\;{\mu}m$ P-V and a surface roughness of $0.1\;{\mu}m\;R_{max}$.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 1995.03a
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• pp.1-8
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• 1995

This paper proposed a simple method for measuring surface roughness of ground surface. utilizing non-contact in-process measuring system using the diode laser. The measurement system is consisted of a laser unit with a diode laser and a cylindrical lens a detecting unit with polygon mirror and CCD array sensor. and a signal processing unit with a computer and device. During operation, this measuring system can provide information on surface roughness in the measuring distance with a single sampling and simultanilusly monitor the state of the grind wheel. The experimental results, showed that the increase of the feed rate and the dressing speed an caused increase in the surface roughness and when the surface roughness is 4Rmax-10Rmax, the cutting speed is 1653m/min-1665m/min. the feed rate is 0.2m/min-0.9m/min, the dressing speed is 0.2mm/rev-0.4mm/rev, the stylus method and the in-process method can be obtained the same results. thus under limited working conditions. using the proposed system. the surface roughness of the ground surface during cylindrical grinding can be obtained through the in-process measurement method using the diode laser.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.3
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• pp.1265-1271
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• 2014

The lamp cooling system of the exposure has effect on the exposure efficiency and device lifetime. In this paper, we performed the numerical analysis about the thermal flow in the lamp housing of the exposure apparatus for the cooling air inflow rate. We set up the velocity of cooling air of side and bottom as the independent variables because cooling performance of the lamp housing is affected by the velocity of the cooling air side and bottom. The cooling state of lamp housing depend on three dependent variables; the temperature at top mirror and exhaust gas, ellipsoidal mirror. Response surface methodology was used in order to establish the efficient cooling analysis plan. The regression equation predicting the variables temperature of lamp housing according to the cooling air velocity were drawn. The velocity of cooling air to reach the optimum temperature of the lamp housing were derived.

• Journal of Korean Ophthalmic Optics Society
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• v.9 no.2
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• pp.417-421
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• 2004

We can see that two images of reflection are observed on the surface of a ophthalmic lens. These are the image reflected from front surface and back surface of lens, respectively. The reflective image shows to be affect by surface refractive power of front and back surface of lens. Total refractive power of lens is calculated by refractive power of front and back surface of lens. Accordingly, the ratio of image on the lens surface is able to measure refractive power of ophthalmic lens without helping of the lensmeter. The ratio of two reflective image measured on the lens surface is compared with the calculated ratio by the power measurement.

• Journal of the Korean Society for Precision Engineering
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• v.20 no.7
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• pp.56-62
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• 2003

The precision fabrication of glass is increasingly demanded for the latest industrial applications of spherical lenses, micro-optical components, and so on. In many cases, the surface roughness of glass is required to be minute for improving the optical characteristics. In this paper, machining characteristics of SF-5 glass and quarts glass are studied by using the ELID grinding process to get mirror surface and productivity compared with a general lapping process. A rotary type grinder with air spindle was used for the experiments. Mitutoyo surface tester and AFM were also used to measure the grinded surface of glass. As the results of experiments, they showed that the surface roughness (Ra) of SF-5 glass was under 7.8 nm and that of quartz glass was under 3.0 m using the # 8000 grinder. So, the possibility of highly efficient and accurate surface for optical components can be achieved by the ELID grinding process.