• Journal of the Korean Society of Manufacturing Process Engineers
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• v.17 no.3
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• pp.1-6
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• 2018

Micro prism pattern is applying in order to get increase of luminance, control the light, and so forth especially in optics and display industry. Most patterns are fabricated by lithography, planning, and EDM, but they have limitations on the productivity or the unit cost of produce. However, ultra precision mold is one of the processes able to replace it, and assure high productivity required by industries. In this investigation, micro prismatic end-milling is suggested in order to fabricate the pattern effectively. Micro prism pattern having $100{\mu}m$ of pitch and height was machined on STD-11. After machining, the flank and boundary wear on micro end mill were measured and analyzed, as well as burr formation and dimensional accuracy of fabricated pattern were evaluated. Thus the optimal cutting conditions were derived.

• Journal of the Korean Society for Precision Engineering
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• v.20 no.7
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• pp.114-119
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• 2003

The aligning between the punch and die governs no only the burr formation characteristics but also the life time of the punch and die in the sheet metal blanking process. There are many ways to adjust the two elements in the general punching systems but in the case of micro punch system, the punch size is reduced to a few tenth of micrometer range and the general aligning methods are almost impossible to apply. The image processing is the most widely used method in micro punch aligning, but in order to apply the method, it needs quite a large space for visionary system to approach the punch-die aligning zone. In this paper, the new punch-die aligning method with using the total capacitance between the punch and die hole is proposed. In this method, the tip surface of the punch tool locates at the same plane of the die surface and the capacitance variation between the two elements are measured. When the center of the two elements are coincided, the capacitance is minimized, but when the align is changed to any direction, the capacitance between the two elements increase. In order to verify the feasibility of this method, the aligning and punching tests was performed.

• Journal of the Korean Society for Precision Engineering
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• v.24 no.11
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• pp.52-58
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• 2007

A cutting device capable of generating various shapes of the cyclic elliptical trajectory of a cutting tool was proposed and micro v-grooving experiments were performed to investigate the characteristics of elliptical vibration cutting (EVC). The proposed cutting device is comprised of a pair of parallel piezoelectric actuators with which harmonic voltages of varying phase difference and magnitude are supplied, creating various shapes of the elliptical tool path. The attributes of the elliptical locus involving the direction of the axis of an ellipse, the rotational direction and amplitudes of a trajectory were fine-tuned for stable operation of the EVC. The EVC characteristics performed with brass and copper revealed reduction in the cutting resistance and suppression of burr formation, resulting in the enhancement of form accuracy of machined micro-features. While the effect of the EVC increases with the increase of excitation frequency and the amplitude, it is found that a change in the cutting force decreases as the amplitude of an elliptical locus increases.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.35 no.8
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• pp.899-904
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• 2011

This This study aims to verify burr formation and to remove the burrs in micro-channel fabrication using micro-machining tools. The machining processes are combined with micro-milling and magnetic abrasive deburring for AISI316 stainless steel. Depending on the micro-milling conditions that are applied, burrs are formed around the side walls. Magnetic abrasive deburring is used to remove these burrs. AISI316 stainless steel is a nonferrous material and its magnetic flux density, which is an important parameter for efficient magnetic abrasive deburring, is low. To enhance this magnetic flux density, we design and build a magnetic array table. The effect of removing burrs is evaluated via SEM and a surface tester.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.10a
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• pp.1049-1052
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• 2002

The aligning between the punch and die governs no only the burr formation characteristics but also the life time of the punch and die in the sheet metal blanking process. There are many ways to adjust the two elements in the general punching systems but in the case of micro punch system, the punch size is reduced to a few tenth of micrometer range and the general aligning methods are almost impossible to apply. The image processing is the most widely used method in micro punch aligning, but in order to apply the method, it needs quite a large space for visionary system to approach the punch-die aligning zone. In this paper, the new punch-die aligning method with using the total capacitance between the punch and die hole is proposed. In this method, the tip surface of the punch tool locates at the same plane of the die surface and the capacitance variation between the two elements are measured. When the center of the two elements are coincided, the capacitance is minimized, but when the align Is changed to any direction, the capacitance between the two elements increase. In order to verify the feasibility of this method, the aligning and punching tests was performed.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2004.11a
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• pp.260-265
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• 2004

LTCC(Low temperature co-fired ceramic) is being recognized as a significant packaging material of electrical devices for the advantages such as relatively low temperature being needed for process, low conductor resistance and high printing resolution. In the process of LTCC electrical devices, the punched via-hole quality is one of the most important factors on the performance of the device. However, its mechanism is very complicated and optimization of the process seems difficult. In this paper, to clarify the process, via-hole punching experiments were carried out and the punched holes were examined in terms of their burr formation. The effects of thickness of PET sheet and ceramic sheet and punch-to-die clearance on via-hole quality were also discussed. Optimum process conditions are proposed and a factor k is introduced to express effect of the process variables.

• Archives of Plastic Surgery
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• v.38 no.1
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• pp.73-76
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• 2011

Purpose: Congenital midline upper lip sinus is a rare lesion. There are two postulates that can account for the formation of the upper lip sinus based on two major theories of the development of the face: the fusion theory and the merging theory. However, congenital midline lower lip sinus is very rarely reported and described. We report a case of a congenital midline sinus of the lower lip in a 6-year-old female. Methods: A 6-year-old girl presented with a nipple like swelling on the midline lower lip. Physical examination revealed about $5{\times}5$ mm protruding round mass with a just small opening that was non-tender to palpation. The mass was not associated with any skin changes. It umbilicated at the apex and contains a fistulous tract, discharging clear fluid. Only, simple radiologic finding shows bony spur on the lower one third of mandibular symphsis. Results: A small transverse ellipse is made around the opening and elevated mass with sharpe dissection. The tract is excised using the probe and dye as the guide. The tract was extended to periosteum of the lower one third of the mandible. The tract and involved periosteum were excised en bloc, and removed protrusion of the mandibular bone using diamond burr. Microscopic examination of the resected sinus revealed the fistulous tract itself, consisting of fibrous connective tissue covered with cornified stratified squamous epithelium, was observed in the center of the sample. In 6 months follow-up, This patient had a good result was obtained by the method of fistulectomy alone. Conclusion: Midline cranoifacial fistulas represent rare lesions resulting from abnormal fusion of embryologic structures. Our case report describes the excision of a congenital midline sinus of the lower lip in a 6-year-old female. This case represents the first report of a lower lip sinus presenting in a girl as a mass in the skin of the chin with extension to the midline of the mandible. However, the etiology of this rare congenital sinus remains obscure.