• Proceedings of the Korean Society of Precision Engineering Conference
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• 1996.04a
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• pp.49-52
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• 1996

The control of diamond turning is usually achieved through a laser-interferometer feedback of slide position. The limitation of this control scheme is that the feedback signal does not account for additional dynamics of the tool post and the material removal process. If the tool post is rigid and the material removal process is relatively static, then such a non-collocated position feedback control scheme may surfice. However, as the accuracy requirement gets tighter and desired surface contours become more complex, the need for a direct tool-tip sensing becomes inevitable. The physical constraints of the machining processprohibit any reasonable implementation of a tool-tip motion measurement. It is proposed that the measured force normalto the face of the workpice can be filterd through an appropriate admittance transfer function to result in the estimated depth of cut. This can be compared to the desired depth of cut to generate the adjustment cotnrol action in addition to position feedback control. In this work, the design methodology on the admittance model-based control with a conventional controller is presented. Based on the empirical data of the cutting dynamics, simulation results are shown.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.10a
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• pp.1466-1469
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• 2004

Micro spherical lens mold processing method based on mechanical one completes a spherical shape by setting a diamond tool of hundreds $\mu$m radius on spins with high speed and then using Z-axis vertical feeding motion like the fabrication of micro drilling. In this method, we can see unprocessed parts shaped like cylinder and cone and check increasing chatter marks and burrs by setting errors of the central axis of rotation on the edge of the tool. That is why this method doesn't suit for the optical lens mold. In this paper presents unprocessed parts are disappeared and chatter marks and burrs are decreased from centre of the lens after using Run-out measuring and setting system on run-out occurred from setting tool. Also the fabrication characteristics of 6：4 Brass, A1601, PMMA are compared and analyzed, establishing the optimum machining condition on each material.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.4 no.2
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• pp.38-45
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• 1995

The diagnosis and monitoring system of abnormal cutting condition is necessary to realize precision machining proces and factory automation, which are final goal of metal cutting in order to develop this system, theimage processing technique has been investigated in machining process. In theis paper, the measurement system of tool wear using computer vision is designed to detect the wear pattern by non-contact and direct method and get the realiable wear information about cutting tool. We measured the area of the side and front part of the diamond core dril which is used in 40kHz ultrasonic vibration machine.

• Journal of the Korean Society for Precision Engineering
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• v.13 no.10
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• pp.154-160
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• 1996

The control of diamond turning is usually achieved through a laser-interferometer feedback of slide position. The limitation of this control scheme is that the feedback signal does not account for additional dynamics of the tool post and the material removal process. If the tool post is rigid and the material removal process is relatively static, then such a non-collocated position feedback control scheme may surfice. However, as the accuracy requirement gets tighter and desired surface cnotours become more complex, the need for a direct tool-tip sensing becomes inevitable. The physical constraints of the machining process prohibit any reasonable implementation of a tool-tip motion measurement. It is proposed that the measured force normal to the face of the workpiece can be filtered through an appropriate admittance transfer function to result in the estimated dapth of cut. This can be compared to the desired depth of cut to generate the adjustment control action in additn to position feedback control. In this work, the design methodology on the admittance model-based control with a conventional controller is presented. The recursive least-squares algorithm with forgetting factor is proposed to identify the parameters and update the cutting process in real time. The normal cutting forces are measured to identify the cutting dynamics in the real diamond turning process using the precision dynamoneter. Based on the parameter estimation of cutting dynamics and the admitance model-based nanodynamic control scheme, simulation results are shown.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.14 no.2
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• pp.8-13
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• 2005

This study proposes the construction of 2-3 dimensional attractor system for cutting characteristics evaluation of metals. Also this paper aims to find the optimal cutting conditions of diamond turning machine by measuring surface form and roughness to perform the cutting experiment of metals, which are aluminum, with diamond tool. As well, according to change cutting conditions such as feed rate, using diamond turning machine to perform cutting processing, by measuring cutting force and surface roughness and according to cutting conditions the aluminum about cutting properties. Trajectory changes in the attractor indicated a substantial difference in attractor characteristics. Constructed 2-3 dimensional attractor system in this study can be used for cutting characteristics evaluation of metals.

• Journal of the Korean Society for Precision Engineering
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• v.21 no.8
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• pp.27-33
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• 2004

The ultra-precision cutting is a key technique for the manufacture of optical components such as aluminium mirrors, electroless nickel mirror, plastic mirror in a variety of advanced science and technology applications. The paper presents experimental results of ultra-precision diamond fuming of electroless nickel materials. In general, the cutting condition such as feed rate and depth of rut, have effect on the surface roughness in ultra-precision diamond turning. To obtain an optimal cutting condition, we studied the effect of the cutting speed. the tool length, the tool nose radius, the feed rate and depth of cut on the surface roughness. So, the relationship of the surface roughness and cutting condition has been clarified. From the experimental results, the machined surface roughnesses were obtained less than 1nm rms.

• 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.

• Journal of the Korean Society for Precision Engineering
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• v.20 no.1
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• pp.63-69
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• 2003

This study proposes the construction of attractor simulator for cutting characteristics evaluation of non-ferrous metals. Also this paper aims to find the optimal cutting conditions of diamond turning machine by measuring surface form and roughness to perform the cutting experiment of non-ferrous metals, which are aluminum, with diamond tool. As well, according to change cutting conditions such as feed rate, cutting force and surface roughness are measured by tool dynamometer. Trajectory changes in the attractor indicated a substantial difference in fractal characteristics. Constructed attractor in this study can be used for cutting characteristics evaluation of non-ferrous metals

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.6 no.4
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• pp.50-56
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• 2007

This study aims to find the optimal cutting conditions, when are IR Detection device HgCdTe is machined with diamond tool of diamond turning machine. Machining technique for HgCdTe with single point diamond turning tool is reported in this paper. The main factors influencing the machined surface quality are discovered and regularities of machining process are drawn. It has been found HgCdTe has more and more important applications in the field of modern optics. The purpose of our research is to find the optimum machining conditions for ductile cutting of HgCdTe and apply the SPDT technique to the manufacturing of ultra precision optical components of brittle materials.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1996.04a
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• pp.29-33
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• 1996

This paper aims to clatify the potimum grinding condition for the electroplated diamond wheel in form grinding of Sr-ferrite. The main conclusions obtained were as follows. (1) The flexural strength and surface roughness of ferrite became the highest at the peripheral wheel speed of 1700m/min. (2) In the case of depth of cut larger than 0.4mm, crack layers is induced in the ground surface, the fracture type of chips exhibits slight ductile mode in the depth of cut smaller than 0.2mm. (3) When the depth of cut exceed 0.6mm, the tool life becomes extermely short due to large chipping and brackage. However, at the depth of cut .geq. 0.05mm, the diamond grain shows abrasive wear. (4) The flexural strength and surface roughness increases in proportion to the feed rate.