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3차원 적층 출력과 밀링에 의해 제작된 일체형 의치의 인공치 변위 평가
곽영훈,이세한,이경제,김희중,Kwak, Young-Hun,Lee, Sea-Han,Lee, Gyeong-Je,Kim, Hee-Jung 대한치과보철학회 2017 대한치과보철학회지 Vol.55 No.4
목적: 의치상과 인공치가 밀링과 3차원 프린팅 방식에 의해 일체형으로 제작될 때 각기 인공치의 변위를 평가하고자 한다. 재료 및 방법: 밀링과 3차원 프린팅 방식으로 상하악 각기 12개의 의치를 제작하였다. 프린팅에 의해 제작된 상악의치 군은 Group Up이고, 하악의치군은 Group Lp이다. 밀링에 의해 제작된 상악의치 군은 Group Um이고, 하악의치 군은 Group Lm이다. 대조군 상악의치는 소프트웨어상에서 최종적으로 디자인된 것으로 상악은 Group Uc이고 하악은 Group Lc이다. 상하악 의치의 양중절치 사이(AB, ab), 양견치 사이(CD, cd), 양제1대구치 사이(EF, ef), 중절치와 제1대구치사이(AE, ae) 및 중절치와 설측점사이(AG, ag) 의 거리를 측정하였다. 결과: AG와 ag는 상하악 의치 모두에서 프린트된 의치군과 컨트롤 의치군 사이에서 뿐 만 아니라 밀링 의치군과 컨트롤 의치군 사이에서도 통계학적 유의성을 나타내었다(One-way ANOVA, P < .05). 하악 일체형의치에서는 Group Lp와 Group Lm 사이에 ab, cd, ef 모두 통계학적 유의성을 나타내었다. 결론: 밀링과 3차원 프린팅에 의해 제작된 의치의 인공치 변위는 통계학적 유의성이 나타났으나, 임상적으로 매우 양호한 변위량을 보여주었다. Purpose: The purpose of this study is to evaluate the displacement of artificial tooth of monolithic complete denture manufactured by milling and 3D printing method in which the denture base and the artificial teeth are simultaneously made. Materials and methods: Twelve upper and lower complete dentures for each were made by milling and 3D printing method. Group Up and Group Lp are a group of upper and lower dentures made by printing, and Group Um and Group Lm are denture groups made by milling. Group Uc and Group Lc are is a group of finally designed upper and lower dentures respectively. Measurements were performed between both central incisors (AB, ab), both canines (CD, cd), both first molars (EF, ef), between an incisor and a first molar (AE, ae), and between incisor and lingual point (AG, ag) for each upper and lower denture. Results: AG and ag value between printed dentures and original ones as well as between milled dentures and original ones showed a statistically significant difference (One-way ANOVA, P<.05) in both lower and upper monolithic dentures. In the lower monolithic ones, ab, cd and ef value revealed a significant difference between Group Lp and Group Lm (One-way ANOVA, P<.05). Conclusion: Dentures made using milling or 3D printers revealed statistically significant difference compared with those of original data. However, it showed clinically very accurate reproducibility.
Hyoung-Tae Lee(이형태),Chul-Woong Hwang(황철웅),Sea-Han Lee(이세한),Duck Hyun Wang(왕덕현) 한국기계가공학회 2021 한국기계가공학회지 Vol.20 No.10
In fine-particle–injection processing, hard fine particles, such as silicon carbide or aluminum oxide, are injected using high-pressure air, and a small amount of material is removed by applying an impact to the workpiece by spraying at high speeds. In this study, a two-axis stage device capable of sequence control was developed to spray various shapes, such as circles and squares, on the surface during the micro-particle jetting process to understand the surface-shape micro-particle-processing characteristics. In the experimental device, two stepper motors were used for the linear movement of the two–degree-of-freedom mechanism. The signal output from the microcontroller is converted into a signal with a current sufficient to drive the stepper motor. The stepper motor rotates precisely in synchronization with the pulse-signal input from the outside, eliminating the need for a separate rotation-angle sensor. The major factors of the processing conditions are fine particles (silicon carbide, aluminum oxide), injection pressure, nozzle diameter, feed rate, and number of injection cycles. They were identified using the ANOVA technique on the design of the experimental method. Based on this, the surface roughness of the spraying surface, surface depth of the spraying surface, and radius of the corner of the spraying surface were measured, and depending on the characteristics, the required spraying conditions were studied.
최성윤(Sung-Yun Choi),이세한(Sea-Han Lee) 한국기계가공학회 2022 한국기계가공학회지 Vol.21 No.12
The water-soluable cutting oil(WSCO) for metal cutting processing is used with 3 to 6 months in general. The used WSCO requiring replacement is wastewater with above the chemical oxygen demand(COD) of 80,000 mg/L and the life of WSCO is closely related to decay. The decay by microorganism is a direct cause of frequent exchange of WSCO. The purpose of this experiment was to develop a multiple purification system for WSCO that efficiently removes fine contaminant particles. 2D concept design was carried out with AutoCAD and the design was drawn by 3D modelling with CATIA. An experiment was conducted to verify the bubble generation capability of the manufactured bubble purifier prototype. As for the experimental method, the nozzle diameter of the bubble purifier, air nozzle interval, atmospheric pressure, water pressure, and water temperature were changed, and the amount and average size of bubbles generated were confirmed by image processing. As a result of the experiment, the smaller the average diameter of the bubbles, the more uniform the size of the generated bubbles and the wider the distribution area.
미세입자 분사가공 시 분사높이 변화에 따른 육각형 가공형상 특성
이형태(Hyoung-Tae Lee),이세한(Sea-Han Lee),왕덕현(Duck Hyun Wang) 한국기계가공학회 2021 한국기계가공학회지 Vol.20 No.9
This study examines the characteristics of spraying conditions based on the change in standoff distance during fine particle spraying while measuring the surface roughness, maximum depth, and maximum width of the sprayed surface. The processing shape of the sprayed surface is analyzed to understand the effects of injection pressure, nozzle diameter, standoff distance, processing shape, processing cycle, processing speed, and injection particles, which are the main factors of fine particle injection processing. Based on the derived characteristics, we attempt to determine the interrelationships of these major factors. The standoff distance is set as a variable factor and a spray machining experiment using a hexagonal shape (from among polygons) instead of square and circular shapes is conducted. Results reveal that research on the characteristics of spraying conditions could be expanded based on changes in the shapes of workpieces.
미세입자 분사가공용 시퀸스 제어가 가능한 2축 스테이지 개발에 관한 연구
황철웅(Chul-Woong Hwang),이세한(Sea-Han Lee),왕덕현(Duck Hyun Wang) 한국기계가공학회 2020 한국기계가공학회지 Vol.19 No.8
A stable rotational-to-linear motion transformation structure using a driving mechanism with 2 degrees of freedom was developed for an orthogonal mechanism to prevent the interference of each axis in 2D motion. In this mechanism, a step motor was used for precise position control. This structure was developed to maneuver workparts in micro particle blast machining experiments. To determine the real-time performance of micro particle blast machining, the control, input, and output were operated simultaneously and precise position control was implemented, using a timer interrupt with multiple execution codes. The two step motors obtained precise position control by removing backlash with a ball-screw mechanism. The device has menu-type control codes for user-friendliness, and real-time sequence control was simultaneously adopted for user control input.
알루미늄 환봉의 나선형 표면 미세입자 분사가공의 조건에 대한 연구
최성윤(Sung-Yun Choi),이은주(Eun-Ju Lee),이세한(Sea-Han Lee),권대규(Dae-Gyu Kwon) 한국기계가공학회 2020 한국기계가공학회지 Vol.19 No.8
The goal of this study is to determine the influence of major factors on the spiral surface microparticle injection machining of cylindrical specimens by the statistical method ANOVA. Before the experiment, rod-shaped test specimens and jigs for helical surface spraying were prepared, and the surface roughness was measured with a surface roughness meter. The injection particle, nozzle diameter, and injection pressure were the primary parameters of the experiment. Other factors that were considered were injection height, injection time, revolutions, and feed distance. The surface roughness after machining was measured, and the effects of the surface roughness data on the primary factors were determined with ANOVA.