• Proceedings of the Korean Society of Precision Engineering Conference
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• 2000.11a
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• pp.963-966
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• 2000

Abrasive jet machining(AJM) process is similar to the sand blasting, and effectively removes hard and brittle materials. AJM has applied to rough working such as deburring and rough finishing. As the needs for machining of ceramics, semiconductor, electronic devices and LCD are increasing, micro AJM was developed, and became the inevitable technique to micromachining. This paper describes the performance of the micro AJM in micro groove cutting of glass. Diameter of hole and width of line in this groove cutting is 80${\mu}{\textrm}{m}$. Experimental results showed good performance in micro groove cutting in glass, but the size of machined groove was increased about 2~4${\mu}{\textrm}{m}$. therefore, this micro AJM could be effectively applied to the micro machining of semiconductor, electronic devices and LCD parts.

• Journal of the Korean Society for Precision Engineering
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• v.18 no.10
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• pp.178-183
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• 2001

Abrasive jet machining(AJM) process is similar to the sand blasting and effectively removes hard and brittle materials. AJM has applied to rough working such as debarring and rough finishing. As the need for machining of ceramics, semiconductor, electronic devices and LCD are increasing, micro AJM is developed, and has become the inevitable technique to micromachining. This paper describes the performance of the micro AJM in micro grooving of glass. Diameter of hole and width of line in grooving is 80${\mu}{\textrm}{m}$. Experimental results showed good performance in micro grooving of glass, but the size of machined groove increased about 2~4${\mu}{\textrm}{m}$. With the fine tuning of masking process and compensation of film wear. this micro AJM could be effectively applied to the micro machining of semiconductor, electronic devices and LCD.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.20 no.4
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• pp.382-385
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• 2011

There is an immense need to obtain nanometric surface finish on optical glass owing to the advantage of improved performance of the components. But owing to brittleness and hardness, optical glass is one of the materials that is difficult to ultra-precision turning. According to the hypothesis of ductile mode machining, regardless of their hardness and brittleness, will undergo a transition from brittle to ductile machining region below a critical undeformed chip thickness. Below this threshold, it is suggested that the energy required for plastic formation. Thus, plastic deformation is the predominant mechanism of material removal in machining these materials in this mode. An experimental study is conducted diamond cutting for machining BK7 glass. The investigation presents the feasibility of achieving nanometric surface and the understanding the mechanism of cutting glass, proving the cutting edge radius effect.

• Laser Solutions
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• v.15 no.3
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• pp.16-19
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• 2012

We have successfully formed brown colored patterns inside of a transparent borosilicate glass generally known as BK7, laying the focus of near infrared Ti: sapphire femtosecond laser beam in the bulk BK7 glass. It is important to keep the laser power well below the damage threshold of BK7 in forming the color center. According to the low laser power, there was no laser induced mechanical damage such as cracks or threads in the color formed area. From the absorbance spectrum and its gaussian fitting, we found the band gap of BK7, 4.21eV, and three absorption edges.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1998.06a
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• pp.427-430
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• 1998

Electro Discharge Machining (EDM) is a so-call non-conventional machining technique. This paper presents the experimental results of an EDM technique for the fabrication of microholes on #7440 pyrex glass substrates. With various applied voltages and at various concentration of NaOH solution, the glass substrates have been microdrilled using the copper electrodes of which diameters are 250 $\mu\textrm{m}$ to 450 $\mu\textrm{m}$. The machined throughholes have been observed the top diameter, the bottom diameter and machining time have been measured. The experimental results show that the machining time decreases as the concentration of NaOH solution increases, the applied voltage increases and the needle diameter decreases. Also, the top diameter increases as the needle diameter increases or the applied voltage increases. The bottom diameter decreases as the needle diameter decreases or the applied voltage decreases.

• Journal of the Korean Society for Precision Engineering
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• v.28 no.6
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• pp.694-700
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• 2011

Since polycrystalline diamond (PCD) has high hardness like diamond, it has been used as tool material for lathe and milling of non-ferrite material. A micro tool fabricated from PCD material can be used for micro machining of hard material such as tungsten carbide, glass, and ceramics. In this paper, micro PCD tools were fabricated by micro EDM (electrical discharge machining) and used for micro grinding of glass. Craters generated on the tool surface by EDM spark work as like grits in grinding process. The effects of tool shapes, tool roughness and PCD grain size were investigated. Also studied was a hybrid process combining electrochemical discharge machining (ECDM) and micro grinding for micro-structuring of glass.

• Journal of the Korean Society for Precision Engineering
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• v.27 no.7
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• pp.87-93
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• 2010

This paper presents an evaluation of efficiency on glass precision machining by using abrasive water-jet machine. In this study, problems of conventional water-jet machining are examined experimentally and are analysized numerically. Especially, the reason of whitening on the machined surface of biochip glass is determined. It is found that the mass flow rate of abrasive input and transverse speed of water-jet are key parameters to control the direct machining of micro hole and channel on a glass substrate. Based on results of experimental analysis, possibility of direct fabrication of micro holes and channels on a glass substrate is successfully confirmed.

• Proceedings of the KIEE Conference
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• 1998.07d
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• pp.1500-1502
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• 1998

Electro Discharge Machining (EDM) is a so-call nonconventional machining technique. This paper presents the experimental results of an EDM technique for the fabircation of microholes on #7440 pyrex glass substrates. With various applied voltages and various concentration of NaOH or KOH solution, the glass substrates have been microdrilled using the copper electrodes of which diameters are 250 ${\mu}m$ to 450 ${\mu}m$. The machined throughholes have been observed the top diameter, the bottom diameter and machining time have been measured. EDM in NaOH solution causes the fabrication to have better the surface condition, higher selective of electrode, lower concentration of solution with respect to EDM in KOH solution machined fabrication.

• Journal of the Korean Society for Precision Engineering
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• v.31 no.1
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• pp.75-81
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• 2014

Laser beam machining has been known as efficient for glass micromachining. It is usually used the ultra-short pulsed laser which is time-consuming and uneconomic process. In order to use economic and powerful long pulsed laser, indirect processing called laser-induced backside wet etching (LIBWE) is good alternative method. In this paper, micromachining of glass using Nd:YAG laser with nanosecond pulsed beam has been attempted. In order to improve shape accuracy, combined processing with magnetic stirrer has been widely used. Magnetic stirrer acts to circulate the solution and remove the bubble but it is not suitable for deep hole machining. To get better effect, ultrasonic vibration was applied for improving shape accuracy.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.11 no.3
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• pp.19-23
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• 2012

Glassy carbon is widely used for high temperature melting process such as quartz due to its thermal stability. For utilizing Classy Carbon to glass mold press(GMP) optical lens, brittleness of Glassy Carbon is main obstacle of ultraprecision machining. Thus authors investigated ductile machining of Glassy Carbon adopting turning and grinding process respectively. From the experiments, ultraprecision turning surfaces resulted brittle crack in all machining conditions and ultraprecision grinding surfaces showed semi-ductile mode in small undeformed chip thickness conditions.