• Proceedings of the Korean Society of Precision Engineering Conference
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• 1996.11a
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• pp.534-537
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• 1996

As consumer electronics, information, and aero-space industry grow, the demand for aspheric lens increases higher. To enhance the precision and productivity of aspheric surface, a CAM system for ultra-precision aspheric surface needs to be realized. In this study, the developed CAM system can generate NC code for various aspheric surfaces fast and precisely by Tri-arc interpolation method that the location of maximum error is fixed. The cutting condition input module and the NC code verification module are adequate to ultra-precision machining, so that a operator can obtain products fast and easily.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2012.10a
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• pp.597-598
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• 2012

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2013.05a
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• pp.47-48
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• 2013

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2007.06a
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• pp.277-278
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• 2007

• Journal of the Korean Society for Precision Engineering
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• v.26 no.1
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• pp.51-56
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• 2009

Recently, with the increasing lightness and miniaturization of high resolution camera phones, the demand for aspheric glass lens has increased because plastic and spherical lens are unable to satisfy the required performance. An aspheric glass lens is fabricated by the high temperature and pressure molding using a tungsten carbide molding core, so precision grinding and coating technology for the molding core surface are required. This study investigates the effect of diamond-like carbon (DLC) and rhenium-iridium (Re-Ir) coating For aspheric molding core surface. The grinding conditions of the tungsten carbide molding core were obtained by design of experiments (DOE) for application in the ultra precision grinding process of the tungsten carbide molding core of the aspheric glass lens used in 5 megapixel, $4{\times}$ zoom camera phone modules. A tungsten carbide molding core was fabricated under this grinding condition and coated with the DLC and Re-Ir coating. By measurements, the effect of DLC and Re-Ir coating on the form accuracy and surface roughness of molding coer was evaluated.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1995.10a
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• pp.276-279
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• 1995

This paper is re;ated to the splits at the side of chips and the changes of surface roughness according to cutting conditions in precsion cutting. Compared with MCD, the surface roughness of workpiece cut by PCD was inferior at a small feed. But, there were no significant difference between MCD and PCD tool above a certain feed in surface roughness

• Journal of the Korean Society for Precision Engineering
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• v.7 no.3
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• pp.37-47
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• 1990

In accordance with the high precision of mechanical elements, it has been required to high precision in surface roughness measurement and, therefore, stylus tip radius is manufa- ctured less than 2 .mu. m through ion sputter machining. In this experiment, by suing ion sputter machined stylus pf fine tip, radius and lapping machined stylus, surface roughness of standard specimens, silicon wafer were measured and then Rmax, Ra, RMS value were investi- gatedaccording to the variation of tip radius of stylus. As a result, measuring error due to the variation of stylus tip radius in surface roughness measurement was decreased by using ion sputter machined stylus and also the measuring accuracy was improved. And the measuring variation of Ra, RMS calculated from correlation coefficient lager than 0.9 on the wave of short period and amplitude using ion sputter machined stylus of fine tip radius.

• Journal of the Korean Society for Precision Engineering
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• v.16 no.7
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• pp.94-100
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• 1999

This study adopted the ultra precision machining system which was composed of an air bearing spindle, a granite bed, air pad and a linear feeding mechanism. It also applied the cutting experiment on the aluminum alloy. To evaluate the safety of high speed machining, we examined the surface roughness according to the changes of cutting speed and obtained the speed limit. This paper also studied the effect of cutting condition such as feed rates and depths of cut on the surface roughness within the speed limit. This provided practical information regarding ultra precision machining.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2003.10a
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• pp.362-367
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• 2003

Recentlry, High accuracy and precision are required in various industrial field. To obtain the surface roughness with range from several 10nm to several nm in inner cutting, we need a ultra-precision machine, single diamond tool, cutting condition, and the study of materials. It is very difficult to obtain the mirror surface without new technique. In this paper, Using the new tool holder as well as the ultra precision diamond cutting, we directly processed the inside of an aluminum alloy in order to obtain mirror surface. We have considered the length of tool holder when we design the tool holder. From experimental results, we believe that the new tool holder will improve inner cutting.

• Journal of the Korean Society for Precision Engineering
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• v.26 no.9
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• pp.58-63
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• 2009

Silicon carbide (SiC) has been used for many engineering applications because of their high strength at high temperatures and high resistances to chemical degradation. SiC is very useful especially for a glass lens mold whose components demanded to the machining with good surface finish and low surface damage. The performance and reliability of optical components are strongly influenced by the surface damage of SiC during grinding process. Therefore, the severe process condition optimization shall be necessary for the highly qualified SiC glass lens mold. Usually the major form of damage in grinding of SiC is a crack occurs at surface and subsurface. The energy introduced in the layers close to the surface leads to the formation of these cracks. The experimental studies have been carried out to get optimum conditions for grinding of silicon carbide. To get the required qualified surface finish in grinding of SiC, the selection of type of the wheel is also important. Grinding processes of sintered SiC work-pieces is carried out with varying wheel type, depth of cut and feed using diamond wheel. The machining result of the surface roughness and the number of flaws, have been analyzed by use of surface profilers and SEM.