• International Journal of Precision Engineering and Manufacturing
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• v.4 no.3
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• pp.55-61
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• 2003

The form accuracy of parts has become an important parameter. Therefore, not only dimensional tolerance but also geometric tolerances are used in the design stage to satisfy the required quality and functions of parts. But the information on the machining conditions, which can satisfy the assigned geometric tolerance in do sign, is insufficient. The objectives of this research are to study the effects of the grinding parameters such as traverse speed, work speed, depth of cut, and dwell time on the after-ground workpiece shape, and to find out the major parameters among them The results are as follows; The effects of work speed and depth of cut on the workpiece shape are negligible compared with the effect of traverse speed. These is an optimal dwell time depending on the traverse speed. The optimal dwell time is decreasing as the traverse speed is increasing.

• Journal of the Korean Ceramic Society
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• v.35 no.1
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• pp.41-47
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• 1998

Cutting and planarization of diamond films have been performed using copper vapor laser under air at-mosphere. Diamond films of about 350${\mu}{\textrm}{m}$ and 800 ${\mu}{\textrm}{m}$ thick have been synthesized with DC plasma assisted chemical vapor deposition. The position of a specimen has been controlled by computer-driven stage. With copper vapor laser beam of 7W cutting depth increases rapidly and saturates with increasing scan number and decreasing scan speed. 8 repetitive scans at scan speed 0.5 mm/sec produce the maximum cutting depth without focus shifting Rod-shape copper vapor laser beam can be made and used effectively in planar-ization of rough diamond surface.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2005.09a
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• pp.110-113
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• 2005

In recent, various shapes of pattern in micron or nano scale are adapted in many applications due to their good mechanical or optical properties. Light guide panel (LGP) of the LCD is one of important applications for micro pattern and micro prism shape is one of the typical patterns. Many applications have the patterns on their surface and the size of the pattern keep decreasing down to the order of micron or even under micron. On the other hand, the area to be patterned keeps enlarging. These two trends in patterned products require tooling micro patterns on large surface, which has still many technical problems to be solved mainly due to pattern size and the tooling area. In this study, we fabricate prism shape of patterns using diamond cutting tool on some metal core and plastic core like PMMA Some of cutting conditions are investigated including cutting force, cutting depth and speed for different core materials.

• Journal of the Semiconductor & Display Technology
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• v.17 no.4
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• pp.46-50
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• 2018

The purpose of this study is to analyze effects of filtering system of cutting fluid which is used for machining silicon electrode. For the research, different sizes of filter clothes are applied to check grain size of sludge of cutting fluid. Surface roughness of machined workpiece, depth of damage inside of silicon electrode, and suspended solids of cutting fluid are experimented and analyzed. From these experiments, it is verified that filtering system of cutting fluid is very important factor for machining. Results of this study can affect various benefits to the semiconductor industry for better productivity and better atmospheric pollution in workplace.

• Journal of the Korean Society for Precision Engineering
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• v.22 no.4
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• pp.167-172
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• 2005

In this paper. micro electrochemical machining (ECM) for micro structure fabrications is presented. By applying ultra short pulses. the chemical reaction can be restricted only to the region very close to the electrode. Micro ECM is applied to machining micro structures through electrochemical milling process becasuse it doesn't suffer from tool wear. Using this method. 3D micro structures were machined on stainless steel. It was found that micro machining is possible with good surface quality in the low concentration electrolyte,0.1 M H₂SO₄. In ECM, as the machining depth increases, better flushing of electrolyte is required for sufficient ion supply. Layer-by-layer milling is advantageous in flushing. However, layer-by-layer milling causes taper of structures. To reduce the taper, application of a disk-type electrode was introduced. By electrochemical milling, various 3D micro structures including a hemisphere with 60 ㎛ diameter were fabricated.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.2 no.1
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• pp.57-62
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• 2003

Machining technique for optical crystals with single point diamond turning tool is reported in tills paper. The main factors influencing the machined surface quality are discovered and regularities of machining process are drawn. Optical crystals have found more and more important applications in the field of modern optics. Optical crystals are mostly brittle materials of poor machinability The traditional machining method is polishing which has many shortcomings such as low production efficiency, poor ability to be automatically controlled and edge effect of the workpiece. SPDT has been widely used in manufacturing optical reflectors of non-ferrous metals such as aluminum and copper which are easy to be machined for 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 our research is to find the optimum machining conditions for ductile cutting of optical crystals and apply the SPDT technique to the manufacturing of ultra precision optical components of brittle materials. As a result, the cutting force is steady, the cutting force range is 0.05-0.08N. The surface roughness is good when spindle is above 1400rpm, and feed rate is small. The influence of depth of cut is very small.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.4 no.2
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• pp.31-36
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• 2005

Machining technique for optical crystals with single point diamond turning tool is reported in this paper. The main factors influencing the machined surface quality are studied and regularities of machining process are drawn. Optical crystals have been known to more and more important applications in the field of modern optics. Ge is more brittle material of poor machinability. The traditional machining method is polishing which has many shortcomings such as low production efficiency, poor ability to be automatically controlled and edge effect of the workpiece. The purpose of our research is to find the optimum machining conditions for ductile cutting of Ge and apply the SPDTM technique to the manufacturing of ultra precision optical components of Ge. As a result, the surface roughness is the best when cutting speed is 180m/min, feed rate is 2mm/min, depth of cut is $0.5{\mu}m$ and nose radius of tool is 0.8mm.

• Laser Solutions
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• v.14 no.1
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• pp.1-5
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• 2011

Photo-induced gratings m flexible PDMS (polydimethly siloxane) film are directly written by a high-intensity femtosecond (130fs) Ti: Sapphire laser (${\lambda}_p$ = 800nm). The refractive index modifications with $4\;{\mu}m$ diameters were photo-induced after the femtosecond irradiation with peak intensities of more than $1{\times}10^{11}W/cm^2$. The graded refractive index profile was fabricated to be a symmetric around the center of the point at which femtosecond laser by controlling both laser power and focused depth. The change on refractive index in the laser-modified regions was estimated to be approximately $10^{-3}$. The internal flexible symmetric diffraction gratings in PDMS film was successfully fabricated using a femtosecond laser.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.18 no.5
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• pp.514-520
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• 2009

Titanium is one of the most attractive materials due to their superior properties of high specific strength and excellent corrosion resistance. The applications in aerospace and medical industries demand machining process more frequently to obtain more precise products. Machining of titanium is faced with strong challenges such as increased component complexity i.e. airframe components manufacturing processes. The machining cost on titanium have traditionally demanded high cutting tool consumable cost and slow machining cycle times. Similarly, the high wear of the cutting tools restricts the cutting process capabilities. Titanium screws applied to fasten parts In the several corrosion environment. In the thread cutting of titanium alloys, the key point for successful work is to select proper cutting methods and tool materials. This study suggests a guidance fur selecting the cutting methods and the tool materials to improve thread quality and productivity. Some experiments investigate surface roughnesses, cutting forces and tool wear with change of various cutting parameters including tool materials, cutting methods, cutting speed. As the results, the P10 type insert tip was assured of the best for thread cutting of Ti-6Al-4V titanium alloy. Also the initial depth of infeed was desirable to use the value below 0.5mm as the uniform cutting area method is applied.

• Proceedings of the KIEE Conference
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• 1999.07g
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• pp.3307-3309
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• 1999

Electrochemical discharge machining (ECDM) is a very recent technique in the fabrication of the micro-electro-mechanical system ( MEMS ) devices. This paper presents the experimental results of the machining of micro-holes on pyrex glass substrates by use of ECDM. Electrolyte is used with a KOH aqueous solution, cathode with copper, anode with platinum, and tool feed system is applied with gravity feed system. Already established experimental results were taken under the condition of constant voltage frequency. However in this paper, the effect of variation of the voltage frequency and duty ratio is considered. In this experiment, it is measured the ECDM performances with variation of the voltage frequency and duty ratio under the conditions of constant other machining variables. ECDM performances are described by the hole depth, and the top hole diameter.