• Proceedings of the Korean Society of Precision Engineering Conference
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• 2009.10a
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• pp.77-78
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• 2009

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2011.06a
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• pp.265-266
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• 2011

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2001.04a
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• pp.938-941
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• 2001

A tool holder system has been designed and builted to measure cutting forces in diamond turning. This system design includes a 3-component piezo-electric tranducer. Initial experiments with tool holder system included verification of its predicted dynamic characteristics as well as a detailed study of cutting parameters. In this research, tool holder system is modeled by considering the element dividing, material properties, and boundary conditions using MSC/PATRAN. Mode and frequency analysis of structure is simulated by MSC/NASTRAN, for the purpose of developing the effective design. In addition, tool holder system is verified by vibration test using accelerometer. Many cutting experiments have been conducted on 6061-T6 aluminum. Tests have involved investigation of velocity effects, and the effects of depth and feedrate on tool force. Cutting velocity has been determined to have negligible effects between 4 and 21㎧.(6) Forces generally increase with increasing depth of cut. Increasing feedrate does not necessarily lead to higher forces. Results suggest that a sample model may not be sufficient to describe the forces produced in the diamond turning process.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.13 no.5
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• pp.64-69
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• 2014

This article presents machining experiments to assess the relationship between the profile accuracy and the workpiece hardness using a natural diamond tool on an ultra-precision diamond turning machine. The study is intended to secure a corner cube prism pattern for reflective film capable of high-quality outcomes. The optical performance levels and edge images of corner cubes having various hardness levels of the copper-coated layer on a carbon steel plate are analyzed. The hardness of the workpiece has a considerable effect on the profile accuracy. The higher the hardness of the workpiece, the better the profile accuracy and the worse the edge wear of the diamond tool.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.309-312
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• 2005

DTM (Diamond Turning Machine) is using for ultra precision manufacturing such as, plastic lens die or aspherical optics. This study is on a design of precision 2-axis stage for DTM. We designed and manufactured a back lash free stage using different weights and measured the positioning accuracy using Interferometer. Also, the 2-D moving accuracy is measured using the high magnification CCD technique. Then, the stage is tested with the machining of spherical and aspherical lens in a DTM with air bearing spindle. It was shown that the back lash free stage is effective for improving the positioning accuracy. Also, positioning control errors in motion control board were able to be found using the proposed stages system.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2003.05a
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• pp.397-401
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• 2003

In this work, diamond turning process is used to produce mirror surface on a Al cone. The Al cone as used as a mirror which can reflect a laser beam without scattering and, hence, it is critical to minimize the surface roughness of a Al cone. During diamond turning, feedrate and tool nose radius are changed to investigate characteristics of the ultra precision machined surface of a Al cone. A laser beam of 633 nm is applied to examine the effect of surface roughness on the characteristics of reflectivity. It is found that surface roughness is not significantly affected by feedrate. The main factor influencing surface roughness is tool nose radius. The line patterns of reflected laser beams show that the minimum surface roughness of 0.08 $\mu\textrm{m}$ (Ra) is required to avoid scattering phenomena of reflectivity.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2000.11a
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• pp.68-71
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• 2000

A tool holder system has been designed to measure cutting forces in diamond turning. This system includes a 3-component piezo-electric tranducer. In this research, tool holder system is modeled by considering the element dividing, material properties, and boundary conditions using MSC/PATRAN. Mode and frequency analysis of structure is simulated by MSC/NASTRAN, for the purpose of developing the effective design. In addition, tool holder system is verified by vibration test using accelerometer. This system will aid to the development of Fast Tool Servo.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.5 no.4
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• pp.27-32
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• 2006

This study aims to find the optimal cutting conditions, when are nonferrous metals(aluminum and silicon) are machined with diamond tool of diamond turning machine. Diamond turning machine has been widely used in manufacturing optical reflectors of nonferrous metals. Such as aluminium and copper are easy to be machined because of their proper ductility. But optical crystals being discussed here are characterized by their high brittleness which makes it difficult to obtain high quality optical surfaces on them. The purpose of this study is to find the optimum machining conditions for ductile cutting of silicon and aluminium.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.10 no.6
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• pp.22-26
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• 2011

The application of fast tool servo (FTS) for diamond turning has been investigated extensively. This paper focuses on the fabrication of the sinusoidal microstructure on a roller, which generated by a piezoelectric-assisted FTS. The influence of the machining parameters on the microstructure configuration was investigated. The experiment results point out that the configuration of the machined microstructure depends mainly on the spindle speed, the diameter of roller and the driving frequency of FTS. The calculation method of the microstructure dimension was reported. The turning test results show that the diamond tool can be moved up to 1kHz without any reinjected vibration in the machining and the peak-to-valley amplitude of the machined sinusoidal microstructure is about 12<${\mu}m$

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2000.05a
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• pp.687-691
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• 2000

Diamond turning machines for manufacture of precision optics require deliberate diagnosis to ensure that all the machine elements are properly operating, kinematically, dynamically and thermally, to produce demanded work qualities. One effective way is to directly inspect topographical features of work surfaces that have been carefully generated with prescribed machining conditions intended to exaggerate faulty consequences of any ill-operating machine elements. In this research, a very-large-scale Phase measuring interferometric system that has been developed for years at Korea Advanced Institute of Science and Technology is used to fulfill the metrological requirements fur the surface analysis. A special stitching technique is used to extend the measuring range, which integrates all the patches that are separately sampled over the whole surface while moving the stage. Then, the measured surface profile is analyzed to releated the machine error sources. For this, zernike polynomial fitting is used together with the wavelet filter and the fourier transform. Experimental results showed that the suggested technique in this study is very effective in diagnosing actual diamond turning machines