• 산업경영시스템학회지
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• 제14권23호
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• pp.71-100
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• 1991

Investment in FA facilities has been accerelated since 1986, turning point by labor strife in Korea firms. Most commonly adopted automation tech, in their manufacturing process consists of NC. Robotics, PLC, CAD/CAM now on and further confused system oriented FMS, CIM, etcs. undergoing. But for all their remarkable notices in manufacturing systems, The competitive position on product cost, quality, shorten delivery and profit has never been recovered in global swing market. To make some empirical suggestions with a view to competitive strategy of Korea firms by FA, to the conclusion largely FA tech. adoption can be justified only when its application on new product productions and improved the structure of products comparatively. Because of when it was applied in old production process. The effectiveness is very doubtful to the lacks of consistent and integrate manufacturing policy with the strategy of the fim and their poor standardization level in shop floors.

• 한국정밀공학회지
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• 제14권3호
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• pp.114-121
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• 1997

In this paper, the automated initial process planning for 3-axis NC machining of sculptured surfaces is persented. The solution algorithms determining three process planning functions, i.e. machining feasibility, setup orientation and feasible machine selection are developed. The machining feasibility is determined by means of BSM(Binary Spherical Map) which derives its solution quickly in algebraic form, and the setup orientation is determined so that the cutting force is minimized. Finally, the feasible machine is determined by computing the minimum motion ranges of each control axisl. The developed algorithms are tested by numerical simulations, convincing they can by readily implemented on the CAD/CAM system as a process planner.

• 구강회복응용과학지
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• 제32권3호
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• pp.246-254
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• 2016

Direct metal laser sintering (DMLS) 방식은 3D 프린팅 중 한 방식으로, 재료를 쌓아가면서 레이저를 이용하여 선택적으로 sintering하는 방식이다. 이는 주조 방식에서 문제되는 결손과 뒤틀림을 방지할 수 있으며 절삭 가공 방식으로 제작하기 어려운 복잡한 구조물을 제작할 수 있다. 본 증례들은 DMLS 방식을 이용하여 지대치 간 길이가 긴 고정성 보철물, 포스트 등 다양한 고정성 보철물을 제작하여 수복하였고, 주기적인 관찰 결과 심미적, 기능적으로 만족할만한 결과를 얻었기에 이를 보고하는 바이다.

• 대한치과보철학회지
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• 제53권4호
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• pp.337-344
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• 2015

목적: 본 연구의 목적은 지대치 삭제의 정확도와 metal coping의 변연적합도와의 상관관계를 알아보는 데 있다. 이를 통해, 세 가지 다른 제작 방식 (주조, milling, 기법)이 이 상관관계에 미치는 영향을 비교해 보고자 한다. 재료 및 방법: 두 개의 master medel을 서로 다른 방식으로 제작하였다; 첫 번째 모델은 치과의사에 의해 deep chamfer margin을 가지도록 지대치 삭제된 것이고, 두 번째 모델은 3-D designing software program을 이용하여 동일한 삭제원칙에 따라 제작되었다. 각각의 모델에 대하여 세 가지 제작 방식으로 코발트-크롬 코핑을 12개씩 제작하여, 총 72개의 시편을 얻었다. 각 시편을 master model상에 적합시키고 공초점 레이저 주사 현미경으로 변연적합도를 측정하였다. 결과: SLS system (P=.0231)과 주조방식(P<.0001)에서는 computer designed model이 hand prepared model에 비하여 유의하게 우수한 변연적합도를 보였다. 그러나 milling group에서는 두 모델 간에 유의한 차이를 나타내지 않았다(P=.9962). 결론: 본 연구에 한하여, 지대치 삭제의 정확도가 금속 코핑의 변연적합도에 미치는 영향은 그 제작 방식에 따라 달랐다. 제작 방식에 따른 변연적 합도는 SLS system이 가장 우수하였고 지대치 삭제의 정확도에 의해 영향을 받았다. 한편, milling 방식은 세 가지 방식 중 가장 큰 변연 격차를 나타내었으며 지대치 삭제의 정확도에 영향을 받지 않았다.

• The Journal of Advanced Prosthodontics
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• 제10권5호
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• pp.354-360
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• 2018

PURPOSE. To compare and analyze trueness and precision of provisional crowns made using stereolithography apparatus and subtractive technology. MATERIALS AND METHODS. Digital impressions were made using a master model and an intraoral scanner and the crowns were designed with CAD software; in total, 22 crowns were produced. After superimposing CAD design data and scan data using a 3D program, quantitative and qualitative data were obtained for analysis of trueness and precision. Statistical analysis was performed using normality test combined with Levene test for equal variance analysis and independent sample t-test. Type 1 error was set at 0.05. RESULTS. Trueness for the outer and inner surfaces of the SLA crown (SLAC) were $49.6{\pm}9.3{\mu}m$ and $22.5{\pm}5.1{\mu}m$, respectively, and those of the subtractive crown (SUBC) were $31.8{\pm}7.5{\mu}m$ and $14.6{\pm}1.2{\mu}m$, respectively. Precision values for the outer and inner surfaces of the SLAC were $18.7{\pm}6.2{\mu}m$ and $26.9{\pm}8.5{\mu}m$, and those of the SUBC were $25.4{\pm}3.1{\mu}m$ and $13.8{\pm}0.6{\mu}m$, respectively. Trueness values for the outer and inner surfaces of the SLAC and SUBC showed statistically significant differences (P<.001). Precision for the inner surface showed significance (P<.03), whereas that for the outer surface showed no significance (P<.58). CONCLUSION. The study demonstrates that provisional crowns produced by subtractive technology are superior to crowns fabricated by stereolithography in terms of accuracy.

• 한국정밀공학회지
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• 제23권9호
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• pp.156-163
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• 2006

The purpose of this study is to improve the machining of free-formed NURBS surfaces using newly defined G-codes which can directly deal with shapes defined from CAD/CAM programs on a surface basis and specialize in rough and finish cut. To this purpose, a NURBS surface interpolation system is proposed in this paper. The proposed interpolation system includes online tool-path planning, real-time interpolation and feedrate regulation considering an effective machining method and minimum machining time all suitable for unit NURBS surface machining. The corresponding algorithms are simultaneously executed in an online manner. The proposed NURBS surface interpolation system is integrated and implemented with a PC-based 3-axis CNC milling system. A graphic user interface (GUI) and a 3D tool-path viewer which interprets the G-codes for NURBS surfaces and displays whole tool-paths are also developed and included in our real-time control system. The proposed system is evaluated through actual machining in terms of size of NC data, machining time, regulation of feedrate and cutting force focused on finish cut in comparison with the existing method.

• 한국정밀공학회지
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• 제19권7호
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• pp.171-179
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• 2002

STEP-NC is the next generation CNC controller taking STEP-based data model as the interface scheme (or language) between CAM and CNC, and carrying out various intelligent functions. At the moment, efforts are being made worldwide to establish international standard for the new interface scheme formalized as ISO14649. As the new language is being established, increasing attention is being paid to the development of the new CNC. Korea STEP-NC is an integrated STEP-NC system taking ISO 14649 as an input, and carrying out various intelligent functions. It is composed of 5 modules: 1) Shop Floor Programming System (PosSFP), 2) Tool Path Generator (PosTPG), 3) Tool Path Viewer (PosTPV), 4) Man Machine Interface (PosMMI), and 5) CNC Kernel (PosCNC). Distinguished from other prototypes (of Europe and USA), the Korea STEP-NC is top-down designed, and bottom-up implemented comprehensively incorporating all the crucial components for realizing the full benefit of STEP-NC paradigm, without using any existing commercial CAD/CAM systems and CNC kernels. The Korea STEP-NC prototype was successfully demonstrated and evaluated in the ISO conventions Together with prototypes of Europe and USA, Korea STEP-NC will be used as a reference system fur the Triangular Conformance Test to be jointly carried out by ISO TC184 SC1, SC4, and IMS Project.

• 구강회복응용과학지
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• 제40권2호
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• pp.72-81
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• 2024

목적: 본 연구의 목적은 가철성 다이 시스템으로 제작된 작업 모형과 솔리드 작업 모형을 이용해 치과용 캐드캠 시스템(CAD/CAM)으로 제작된 지르코니아 3본 고정성 치과 보철물의 변연 및 내부 적합성을 평가하고자 하였다. 연구 재료 및 방법: 하악 우측 제1소구치와 하악 우측 제1대구치에 지르코니아 크라운을 위한 치아 삭제 프로토콜을 수행하고, 하악 우측 제2소구치가 없는 레퍼런스 모델을 만들었다. 레퍼런스 모델은 폴리비닐 실록산 인상체를 사용하여 복제되었고, 일반적인 치과 기공 절차에 따라 20개의 작업 모형이 제작되었다. 비교 분석을 위해, 10개의 지르코니아 3본 고정성 치과 보철물은 가철성 다이 시스템에서, 나머지 10개는 솔리드 작업 모형에서 제작되었다. 모든 작업 모형은 치과용 데스크탑 스캐너를 사용하여 디지털화되었고, 캐드 소프트웨어에서 보철물을 설계하였다. 최종 3본 고정성 치과 보철물은 밀링 과정을 통해 제작되었다. 변연 및 내부 적합도 평가는 레퍼런스 모델에 제작된 보철물을 위치시키고, 디지털 평가 방법으로 적합도가 측정되었다. 두 그룹 간의 통계 비교를 위해 Mann-Whitney U 검정이 적용되었다(α = 0.05). 결과: 가철성 다이 그룹은 솔리드 작업 모형 그룹에 비해 소구치와 대구치에서 유의하게 높은 적합도 차이를 보였으며(P < 0.05), 특히 변연 및 교합 간격에서 유의하게 높은 편차를 보였다. 색상 편차 맵에서도 가철성 다이 그룹이 변연 및 교합 영역에서 더욱 높은 편차를 보였다. 결론: 3본 고정성 치과 보철물의 적합도 차이는 가철성 다이 시스템의 작업 모형 상에서 제작된 치과 보철물에서 초래되었으며, 이를 통해 가철성 다이 제작 방법이 치과 고정성 보철물의 정확성에 영향이 있었음을 검증하였다.

• 한국CDE학회논문집
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• 제9권4호
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• pp.406-415
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• 2004

The industrial environment for shipbuilding in 21st century requires increase in few type of ships and marine structures, international cooperation and globalization, while virtual enterprise environment is rapidly establishing. On the other hand, more and more efforts will be spent on internet based distributed and collaborative environment rather than being spent on unit level automations such as CAD, CAM and CAE, and the link between them. Recent internet technology and information technology in heterogeneous environment are being applied in shipbuilding industry as well as in other industries. While these technology are rapidly adopted in major shipyards, many small and medium-sized shipyards does not have enough resources to introduce system designed for large enterprise. In this paper, a prototype of Internet technology based basic planning system is implemented for the small and medium sized shipyards based on the internet technology and concurrent engineering concept. First, the system is designed from the user requirements. Then standardized development environment and tools are selected. These tools are used for defining and evaluating core application technologies for the system development. This can guarantee the survival of small and medium-sized shipyards in 21st century industrial environment.

• 대한심미치과학회지
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• 제5권1호
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• pp.34-43
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• 1996

In nowdays many dental CAD/CAM system were developed. Among those only Cerec and Celay were used globally as clinical application. Celay is a machinable ceramic system that is capable of milling inlays, onlays, and veneers from prefabricated industrial ceramic blocks(Vita Celay Blanks). The advatages of Celay are to simplify the manufactures and to save the processing time. For esthetics In-Ceram Alumina bridges were introduced into maxillary anterior restoration. They have a high strength, a high translucency and an excellent marginal adapation. But the laboratory processes are very difficult and complicated. So the construction of In-Ceram Alumina bridge combined with celay system was desgined. The patient is a 28 year old age male. The chief complain is missing of maxillary left central incisor. He wants to restore anterior bridge for esthetically. The Alumina bridge framework was constructed easily by celay system. Glass ilfiltration was occurred. After that, vitadura-${\alpha}$porcelain build up was occurred by conventional method. The translucency of In-Ceram Alumina 3 unit bridge revealed to be superior to that of porcelain fused to metal bridge. So we report it with clincal case and literature reviews.