• 한국정밀공학회지
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• 제18권2호
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• pp.84-89
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• 2001

In recent years, there is increasing demand of esthetic design and complex function in aerospace, automobile and die/mold industry, which brings into limelight high-precision, high-efficient machining of sculptured surface. This paper deals with the establishment of the optimal tool path on free form surface in high speed ball end milling. Ball end milling is widely used for free form surface die and mold. In this machining, the cutting direction was changed with tool path. The cutting characteristics, such as cutting force and surface form are varied according to the variation of cutting directions. In this paper, the optimal tool path with down cutting in free form surface cutting is suggested.

• 한국산학기술학회논문지
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• 제20권1호
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• pp.290-296
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• 2019

차량용 HUD는 자동차 전면 유리창에 안전 운전과 편의 운전 관련 다양한 정보를 표시해 주는 장치로 중요한 역할을 수행한다. 본 논문에서는 증강현실 기술에 적용이 가능한 대면적 비구면 자유형상 미러를 가공하기 위해 초정밀 가공기를 이용하여 가공을 실시하였고 그 결과를 측정하였다. 초정밀 다이아몬드 절삭은 정밀도가 높을 뿐만 아니라 표면 거칠기와 잔류 응력을 낮게 할 수 있어서 우수한 표면 무결성을 갖는 고급 부품의 생산에 유리하다. 또한 비구면 자유 형상의 몰드를 사용함으로써 광학 전달 함수의 개선, 왜곡 경로의 감소 및 특수 이미지 필드 곡률의 실현과 같은 장점을 얻을 수 있다. 이와 같은 비구면 자유형상 금형을 가공하기 위한 방법으로는 초정밀가공기를 이용한 다이아몬드 절삭 방법을 사용하였으며, 제작된 비구면 자유형상 미러 금형의 평가는 비구면 형상 측정기를 이용하여 실시하였다. 이러한 방법에 의해 $1{\mu}m$ 이하의 형상 정밀도(PV)와 $0.02{\mu}m$ 이하의 표면 거칠기(Ra)를 갖는 비구면 자유형상 금형을 제작할 수 있었다.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2018년도 춘계 학술논문 발표대회
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• pp.112-113
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• 2018

As the building becomes more sophisticated, indoors and outdoors exterior decoration of construction has been increased. However, it is very difficult to produce an FDM(Free-form Decorative Mold) that meets the requirements of quality, durability, and ease of installation, resulting in a high cost. Therefore, the objective of this study is basic research for economical production of FDM production technology while satisfying the above requirements. For this study, the authors analyze the details of the shape and requirements of the FDM, and the production details and processes that reflect the characteristics. The results of this study can utilize to develop algorithms for production and management of academically efficient FDM and can utilize to secure FDM production technology at commercial level.

• 한국건축시공학회지
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• 제23권3호
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• pp.251-260
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• 2023

비정형 건축물은 외부면이 다양한 곡선이기 때문에 비정형 거푸집은 맞춤제작되어 사용된다. 비정형 거푸집 제작에 있어 재활용이 가능한 Phase Change Material(PCM)과 곡률구현에 용이한 Ultra-High Performance Concrete(UHPC)가 사용된다. 그러나 PCM은 약 58~64℃가 융점이며, UHPC의 수화열로 PCM 거푸집이 손상될 수 있어 실험을 통해 형상을 확인한다. 실험은 제작한 PCM 거푸집에 Silicone sheet 3mm를 설치한 (A)와 설치하지 않은 (B) 거푸집에 UHPC를 타설한다. 실험결과 (A) 3.793mm, (B) 5.72mm가 측정되었으며, (B) 거푸집이 수화열에 취약한 것으로 분석되었다. 이러한 연구는 초고강도 비정형 패널 및 PCM 거푸집 제작 관련 기초자료로 활용될 것으로 기대된다.

• 국제학술발표논문집
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• The 6th International Conference on Construction Engineering and Project Management
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• pp.401-404
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• 2015

Demand on free-form buildings is gradually increasing, yet owing to the difficulty of production-installation work, several problems occur in the construction phase upon construction of a building, including the increased cost and construction duration, and reduced constructibility. To solve these problems, a techonology to produce FCP using a CNC(Computerized Numeric Control) machine is developed. The technology is that the information of designed free-form buildings to the CNC machine is transferred, and the transferred information is used for RTM(Rod-Type Mold, the mold shaped by back-up rods) and PCM(Phase Change Material) shaping, and the shaped RTM and PCM have the role of molds to produce FCP. Construction duration and project cost are limited in building sites, so the efficiency of processes like production-installation of FCP for application of the technology is significant. Since it is almost impossible to change the production-installation process at the construction phase when they are established, process should be deliberately decided. Therefore, the purpose of the study is to propose a production-installation simulation model of free-form concrete panels, in aspect of PCM. This paper is establishing the process for production-installation of FCP, estimating time required by each construction type and proposing a time simulation model that changes according to various constraints based on the analyses. With the time simulation model, it will be possible to build a cost model and to review the optimal construction duration and project cost.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2008년도 하계학술대회 논문집 Vol.9
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• pp.452-452
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• 2008

Abstract Head-mounted displays(HMD) are being developed and marketed in growing numbers for a variety of applications. Though most commonly associated with entertainment applications other applications are also being developed. The field vision on the display screens is expanded by the optical system producing an imaginary screen that appears to be positioned several meters in front of the viewer. In this study, the mold core for the prism lens of HMD was processed by fly-cutting method, and the form accuracy of the mold core was measured.

• 대한기계학회논문집A
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• 제36권3호
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• pp.259-264
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• 2012

비자성체의 자유곡면 자기연마 공정에서 자기력 세기의 향상은 매우 중요하다. 비자성체 자유곡면의 표면에 발생하는 자기력의 세기에 따라 자기연마 입자가 가지는 수직 절삭력이 변화하기 때문이다. 이러한 자기력 향상을 위하여 전자석 배열 테이블이 적용된 제 2세대 자기연마공정이 비자성체의 자유곡면 자기연마에 적용된다. 본 연구에서는 이러한 제 2세대 자기연마공정에서 전자석 배열 테이블에 발생하는 자기력 세기 향상을 위한 극성배열 방법을 제시하고 이를 알루미늄합금의 곡률 자기연마에 적용하였다. 그 결과 볼록 및 오목 형상에서 각각 S-N-S와 S-N-N-N-S 극성 배열에서 가장 높은 표면거칠기의 향상을 확인하였다. 또한 상승 가공경로에서 상대적으로 높은 표면거칠기 향상을 나타내었다.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2014년도 춘계 학술논문 발표대회
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• pp.64-65
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• 2014

Recently freeform buildings which are free from simple shape are implemented depending on improvement of construction method. However, freeform buildings are spent more time and cost to materialize than typical form. Because molds for production of freeform shape cannot be reused. For these reasons, low productivity, delay of construction schedule and budget overflow are occurred. Thus, technology of molds need to be developed for manufacturing of freeform concrete segments. The objective of this study is manufacturing of freeform concrete segments using rod type mold. This technology can implement not only application to various shape but also mass production. Thus, problems of construction period, productivity and cost can be solved. After this study, productivity analysis should be continued through the field application.

• 한국정밀공학회지
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• 제18권3호
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• pp.47-52
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• 2001

Rapid Prototyping(RP) has been widely applied in designing and developing process of new products. RP can reduce the lead time and expense required to bring a new product form initial concept to production. Among several RP process can dramatically reduce the total build time and be applied for fabrication of large-sized and free form object because it uses in LOM the paper thickness is 0.05∼0.38mm as deposition feature segment. In this study, mechanical properties of pattern with LOM system is studied for optimal design of sand mold casting. The main result is that tensile, compressive strength and pattern size are significantly affected by temperature of hot roll.

• 한국의류산업학회지
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• 제24권4호
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• pp.443-450
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• 2022

This study developed a three-dimensional helmet mold design software that can design helmets for treating the infant plagiocephaly (flat head syndrome) using three-dimensional head scan data. For this, the three-dimensional head data of sixth SizeKorea body measurement project as well as the data produced by a head modeling software were used to prepare the head shape data of plagiocephaly patients. A total of 14 landmarks and 10 dimensions of heads required for helmet mold shape design and plagiocephaly diagnosis were automatically measured using an anthropometric analysis software. Using the software developed in this study, plagiocephaly can be diagnosed not only visually by three-dimensional head data visualization but also quantitatively by calculating the medically defined indices such as cranial index, which measures the proportions of the head, and the cranial vault asymmetry index, which measures the asymmetry of the head. The basic shape of the helmet mold was automatically generated based on the head scan data. Additionally, it is possible to fine tune the shape of the mold to reflect individual characteristics by using a free form deformation technique. Finally, the designed helmet mold was converted into the data that can be printed on a three-dimensional printer for generating the actual prototype.