• Journal of the korean academy of Pediatric Dentistry
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• v.30 no.3
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• pp.520-529
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• 2003

Proper finishing and polishing of tooth restorations enhance the esthetics and the longevity of the restored tooth. The aims of this study were to identify an appropriate polishing system for each esthetic restorative material(Z250, Heliomolar, Dyract AP, Fuji II LC), and to compare the efficiency of polishing systems(Enhance, Sof-Lex, Composite). The control group remains untouched. The results were as follows: 1. There was no significant difference of surface roughness among the materials, while a roughness value of Z250 was the lowest of all. 2. The smoothest surface was produced by Mylar sheet on all materials. The polishing procedures, however, increased a roughness value. 3. The smoothest surfaces were produced by Sof-Lex, and there was significant difference of surface roughness between Sof-Lex and Enhance systems. 4. The smoother surfaces on the control group showed many scratches after the polishing procedures in the SEM findings.

• Journal of Dental Rehabilitation and Applied Science
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• v.30 no.2
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• pp.131-137
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• 2014

Purpose: This study examined the efficiency and wear of periodontal instrument sharpening using aluminum oxide stones with different levels of roughness. Materials and Methods: Thirty new No. 9-10 Gracey curets were used in this study. All curets had become dull after scaling and root planing. After similar blunting, the instruments were divided randomly into three groups (240, 600, 800 grit) containing 10 curets each. The stones were applied correctly to the lateral surface of each curet to maintain the $70-80^{\circ}$ angle. After resharpening, sharpness of the curets was examined by an optical microscope. After 20, 40, 60, and 80 strokes, the wear was measured at 1 mm and 2 mm from the tip of the cutting edge using a digital caliper. The data was analyzed statistically using analysis of variance (ANOVA) with repeated measures, 2-way ANOVA, and a Fisher's exact test. Results: The degree of sharpness increased significantly (P < 0.001) as the number of sharpening strokes grew for all stones. A comparison of the degree of sharpness on the same number of strokes showed that the 240 grit group significantly excelled the other groups on 5 and 10 strokes, respectively (P < 0.001). The mean wear showed no statistically significant difference among the groups (P > 0.05). Conclusion: The efficiency of Gracey curet resharpening was enhanced with more coarse stones, though we should consider the wear of the instrument during resharpening.

• Journal of the Korean Society for Precision Engineering
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• v.14 no.1
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• pp.69-77
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• 1997

본 논문은 금형의 마무리 연마 작업을 로봇을 이용하여 자동화하기 위한 오프라인 프로그래밍 시스템개발을 그 내용으로 하고있다. 3차원 자유곡면 형상을 갖는 금형을 연마하기 위한 로봇 작업 경로를 효율적으로 생성하기 위해서는 기존의 교시 방법이 아닌 CAD시스템과 연계된 시뮬레이션 방식의 자동 경로 생성 방법이 요구된다. 본 연구에서 개발된 금형 연마 작업을 위한 오프라인 프로그래밍 시스템은 연마 작업 시뮬레이션을 위한 기하학적 모델링 기능, 로봇의 작업 공간을 고려한 작업장 배치 기능, 연마 로봇의 효율적인 기구학 해, 3차원 그래픽 시뮬레이션, 3차원 물체간의 충돌 검사 기능 및 유기적인 관계형 데이타 베이스 기능 등으로 구성된다. 본 시스템의 시뮬레이션 결과를 로봇의 위치 보정 과정을 거쳐 로봇 작업 프로그램 으로 변환함으로써 최종적으로 실제 연마 작업이 가능한, 정확하고 안전한 로봇 프로그램을 생성하였다.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2000.05a
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• pp.850-853
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• 2000

최근에 초정밀 제조업 분야에서 볼의 이용에 관한 연구가 급속히 진행되고 있으며, 일부 반도체 분야에서는 BGA(Ball Grid Array)와 같은 용도로 이용되기도 하며, 볼 자체를 반도체 칩으로 응용하려는 시도가 제안되어 있다. 이러한 적용분야들에서 볼의 진구도, 정밀도 및 청정도 등을 만족시킬 수 있는 가공기술이 선결되어야 한다. 본 연구에서는 초정밀 볼의 가공기술 개발을 목적으로 하여 유리 볼을 대상으로 하고 $H_2O$와 CeO$_2$를 혼합한 연마재를 사용하여 부상회전에 의한 비접촉식 연마방법을 제안하고 가공특성을 조사하였다 연구 결과로서, 비 접촉식 볼의 가공에서는 가공에 앞서 $H_2O$와의 전처리 과정을 거침으로 해서 가공속도를 촉진시킬 수 있다는 사실이 확인되었다.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2012.05a
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• pp.303-304
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• 2012

공업적으로 널리 사용되는 내식강의 전해연마는 주로 고농도의 인산염 전해액 기반에 황산과 질산 첨가된 용액에서 $70^{\circ}C$ 이상의 고온에서 행해지다 보니 폐액 처리와 작업 환경이 좋지 않아 기피 기술로 인식 되어 있다. 본 연구에서는 환경 친화적인 상온 공정을 개발 하고자 에틸렌 글리콜 용액에 여러 가지 첨가제를 첨가하여 그 효과를 살펴보고 최적 조성과 공정 조건을 확립 하고자 하였다. 틸렌 글리콜에 물과 질산 암모니움을 첨가하여 점도와 pH, 전류 전압 특성을 구하고 여기에 첨가제인 설파메이트와 암모니움 클로라이드 첨가량을 정하고 각각의 효과를 확인 하였다. 이러한 결과를 바탕으로 SUS 316 재질에 대한 최적 연마조건을 설정하기 위해 조도 변화, 광택도 및 표면 조직 변화와 전해연마기구를 비교 검토하였다.

• Journal of Dental Rehabilitation and Applied Science
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• v.34 no.1
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• pp.39-45
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• 2018

Purpose: The purpose of this study was to evaluate the clinical effects of erythritol powder air polishing device (EPAP) in addition to scaling and root planing (SRP) in non-surgical periodontal treatment in moderate chronic periodontitis patients. Materials and Methods: Clinical evaluation was performed at 21 sites treated with SRP (control) and 21 sites treated with the addition of SRP+EPAP (test). All examinations were performed before treatment, 1 month after treatment, and 3 months after treatment. Depth of the periodontal pocket, gingival recession, clinical attachment level, plaque index, and bleeding of probing were measured as clinical parameters. Results: In both test and control groups, there was a significant decrease in the depth of the periodontal pocket, plaque index, bleeding of probing, increased gingival recession, and gain of clinical attachment level at 1 month and 3 months after treatment. However, there was no significant clinical difference between the test group and the control group. Clinical result was improved after 1 month compared to the baseline; in contrast, results at 3 months after treatment were worse than at 1 month after treatment. Conclusion: In this study, we cannot suggest that SRP + EPAP is clinically more effective than SRP alone as non-surgical periodontal treatments. Periodic periodontal therapy, at intervals of at least every three months, is important for sustaining effects of this treatment.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.16 no.6
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• pp.133-139
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• 2007

In this paper, optics polishing technology using adaptive tool and eccentric motion mechanism was suggested. Optics polishing can make high reflective and accurate surface. The optics polishing process based on the eccentric motion mechanism has been used to manufacture the ophthalmic lens mold. Also ophthalmic lens mold factory hold conventionally a lot of the curved polishing tools for the versatile mold curves of eye diopters and want to reduce tool numbers. Therefore, a polishing machine with adaptive airbag tool was developed and experimentally verified in view of surface roughness and form accuracy.

• ETRI Journal
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• v.14 no.1
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• pp.108-117
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• 1992

광통신 시스팀에서 신호접속용으로 사용되는 광커넥터의 결합기구 중 세라믹 페룰-슬리브의 정렬기구에서 발생하는 성능저하 현상을 다루었다. 성능저하 현상으로 페룰 단면연마시 발생하는 Vertex Eccentricty, 좌굴현상, 환경에 따른 탄성 및 응력의 변화, 마모, 피로파괴 등에 대한 이론적인 배경과 실험결과를 토대로 특성에 대한 영향을 분석하였다.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.10a
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• pp.76-76
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• 2003

• Journal of the Korean Society for Precision Engineering
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• v.18 no.7
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• pp.65-71
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• 2001

The development process of the polishing system for the aspherical lens mold for opto-electronics industry is described. The system uses the method that polishing tool is scanned on the surface under PC-NC control for the aspherical lens mold. The two axes interpolation of the minimum translation mechanism is applied to give uniform working condition by motion analysis. An aspherical surface is divided into multiple sections and each dwell time is calculated from the polishing rate model based on the Preston equation. As result of form error compensation experiment, initial form error is decreased about 25% while an average value of surface roughness is also reduced successfully from 180nm to 19nm.