• Title/Summary/Keyword: STL

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A Viewer Development for Various Material Agile Prototyping System (다중재료 쾌속가공시스템을 위한 뷰어 구현)

  • 천인국;김승우;안덕상;주영철
    • Proceedings of the Korea Multimedia Society Conference
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    • 2001.06a
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    • pp.307-311
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    • 2001
  • 신속조형시스템(RP : Rapid Prototyping)용 자료교환 표준인 STL의 자료구조는 단순하고, 조형용 2차원 단면 자료로의 전환이 용이하며, 생산 가공 기술로서의 현대적인 특성(신속성, 조형성, 경제성, 청정성 등)을 가지고 이는 장점이 있는 반면에, STL 3D 좌표값의 기준(좌표계의 원점)이 되는 크기 정보가 없다. 이런 문제를 구현된 STL 뷰어에서는, 스케일링(scaling) 기법과 선형적인 이동 기법을 사용하여 해결하였고, CAD 시스템으로 제작된 파일 자체의 문제점 패싯(facet) 중복, 정밀도, 법선 벡터 값의 오류 등도 검증기(verifier)와 오류 정정기(error corrector)글 구현하여 해결하였다. 제안된 방법으로 구현된 STL 뷰어는 시스템의 안정성과 확장성, 그리고 효율성 측면에서 우수한 성능을 보였으며, 슬라이싱(slicing), 경로 추적기(path tracer)의 전처리기의 역할을 한다.

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Delaunay triangulation for efficient reduction of measured point data (측정데이터의 효율적 감소를 위한 De Iaunay 삼각형 분할의 적용)

  • 허성민;김호찬;이석희
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2001.04a
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    • pp.53-56
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    • 2001
  • Reverse engineering has been widely used for the shape reconstruction of an object without CAD data and it includes some steps such as scanning of a clay or wood model, and generating some manufacturing data in an STL file. A new approach to remove point data with Delaunay triangulation is introduced to deal with the size problems of STL file and the difficulties in the operation of RP process. This approach can be used to reduce a number of measuring data from laser scanner within a specified tolerance, thus it can avoid the time for handing point data during modeling process and the time for verifying and slicing STL model during RP process. Developed software enables the user to specify the criteria for the selection of group of triangles either by the angle between triangles or the percentage of triangles reduced, and thus RP models with accuracy will be helpful to automated process.

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Reduction of processing time for concept printer with model splitting (모델 분할을 이용한 컨셉 프린터의 가공시간 단축)

  • Lee, In-Tak;Kim, Ho-Chan;Guen, Min-Hyung;Lee, Suk;Lee, Seok-Hee
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 1997.10a
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    • pp.105-108
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    • 1997
  • To reduce design period, demands for rapid prototyping system is increasing. Among the rapid prototyping system, as a concept modeler, 3D Printer appears before the footlights. In spite of short production time and convenience, 3D Printer causes post processing problem. And that is too slow to adapt to the demand of workshop. In this research, we developed a system for reducing build time and roughness using splitting operation. Also, propose BFS(B-rep For STL) data structure to maintain model data, split STL model and implement Euler Operation for input and output.

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Development of Stereolithography system using X-Y robot (X-Y 로봇을 이용한 광조형시스템 개발)

  • 김준안
    • Journal of the Korean Society of Manufacturing Technology Engineers
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    • v.5 no.4
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    • pp.18-25
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    • 1996
  • In this study, we have developed the stereolithography system that supports the development of a products. This paper presents the development of the stereolithography system. The system is composed of hardware, software and control part. The software converts a STL file to NC data and displays the monitoring figure in control part. The hardware part deals with structure of machine. The most important theme in this paper is LG-SLCAM software. This software can generate NC data and scanning condition data from a STL file semiautimatically. On the basis of three diensional shapes, it makes data for support structure from STL file. The effectiveness of using out stereolithography system is confirmed by processes of good development.

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Verification of Build Part and Tool Paths for Metal 3-D Printing Process (3차원 금속 프린팅 공정에서의 조형파트 진단 및 조형공구경로 검증)

  • Lee, Kyubok;Jee, Haeseong
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.41 no.2
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    • pp.103-109
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    • 2017
  • Metal 3D printing, which is an additive metal manufacturing (AMM) process, enables the development of full-density metallic tools and parts using metal powders that are precisely delivered and controlled for deposition with no powder bed. However, some unknown geometric defects and irregular geometric features on an STL model can possibly result in incorrect metal part fabrication after the build. This study first proposes a methodical approach for verifying the build part, including the missing facet problems in an STL model, by defining some irregular features that possibly exist on the part. Second, 2D tool paths on each build layer were investigated for detecting any singular region inside the layer. The method was implemented for building two sample STL models using a direct energy deposition process, and finally, it was visually simulated for diagnosis.

A study on the sound transmission through double plates installed inside an impedance tube (임피던스 튜브 내에 설치된 이중 평판의 음파투과연구)

  • Kim, Hyun-Sil;Kim, Bong-Ki;Kim, Sang-Ryul;Seo, Yun-Ho;Ma, Pyung-Sik
    • The Journal of the Acoustical Society of Korea
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    • v.35 no.4
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    • pp.253-260
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    • 2016
  • In this paper, derivation of the STL (Sound Transmission Loss) of the double plates installed in an impedance tube is discussed using an analytic method, where an air cavity exists between the plates. Vibration of the plates and sound pressure field inside the tube are expressed in terms of infinite series of modal functions. Under the plane wave assumption, it is shown that consideration of the first few modes yields sufficiently accurate results, and locations of peaks and dips are investigated. It is determined that the peak frequencies of the double plates coincide with those of each single plate. When the two plates are identical, the STL of the double plates as well as that of the single plate become zero at the natural frequencies of the single plate. The location and amplitude of the dips are investigated using an approximation solution when the cavity depth is very small.

Evaluation of Sound Insulation Performance of a Unit Cabin Mock-up (유니트 캐빈 목업(mock-up)의 차음성능평가)

  • Kim, Hyun-Sil;Kim, Sang-Ryul;Kim, Bong-Ki;Kim, Jae-Seung;Lee, Sung-Hyun
    • Journal of the Society of Naval Architects of Korea
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    • v.48 no.1
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    • pp.49-55
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    • 2011
  • Sound insulation performance of a unit cabin mock-up is studied, where two identical rooms simulating cruise ship cabin are installed. STL (Sound Transmission Loss) measurement in the mock-up shows that STL of the partition between rooms is degraded by imperfect door ceiling and gap between wall and floor. It is also observed that gap around lighting and electrical outlet slightly affect the STL in high frequency ranges, since lighting and electrical outlet are supported by mineral wool in the back side due to fire-resistance requirement. Even after all possible gaps are sealed, STL of the partition is found to be lower than that measured in the laboratory by 9 dB. Measurement of SBN (Structure-Borne Noise) reveals that flanking transmission of SBN along the steel deck floor can severely deteriorate STL of the partition. Statistical energy analysis (SEA) of the mock-up confirms importance of the floor SBN control, in which increasing damping is essential to ensure high STL.

Study on the selected by management streams for improvement of water quality in dam-reservoir (댐-호소의 수질개선을 위한 관리 하천 선정에 관한 연구)

  • Yonghun Choi;Gwanjae Lee;Sangjoon Bak;Yeonji Jeong;Kyoungjae Lim
    • Proceedings of the Korea Water Resources Association Conference
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    • 2023.05a
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    • pp.265-265
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    • 2023
  • 유역모형을 통해 우심하천을 제시하는 방법은 많은 노력과 시간이 요구되는 경우가 많다. 본 연구에서는 국가배출부하량 자료를 사용하여 간단하게 오염원별/오염물질별 수질 관리가 요구되는 하천을 선정하는 방법을 제시하고, 우심하천을 선정하였다. 적용 유역은 한강 수계에서 가장 복합한 댐 유역인 충주댐 유역으로 결정하였다. 충주댐 유역의 소유역별 배출부하량을 활용해 하천 관점의 배출부하량을 산정하였다. 하천 관점의 배출부하량 (Stream Total Loads, STL로 명명)은 임의의 하천으로 유입되는 모든 소유역의 배출부하량 합계를 면적 합계로 나누어 산정하는 방법이며, 임의의 하천 지점에서 상류의 모든 소유역이 포함된 단위면적당 배출부하를 의미한다. 따라서 댐 유역 말단의 STL은 유역 전체의 단위면적당 배출부하로 표현되며, 유역 전체의 STL보다 높은 소유역이 연결된 하천을 댐 호소 관점에서 볼 때 관리가 필요한 하천이라 할 수 있다. 댐 유역 말단의 STL은 점오염원-BOD 0.617 kg/km2/day, 점오염원-TP 0.038 kg/km2/day, 비점오염원-BOD 2.909 kg/km2/day, 비점오염원-TP 0.237 kg/km2/day로 산정되었다. 점오염원에 대한 BOD 관리하천은 창리천, 장평천, 지장천하류 등 15개 소유역, TP 관리하천은 주천강시점, 창리천, 주천강상류 등 20개 소유역으로 나타났다. 비점오염에 대한 BOD 관리하천은 주천강시점, 장평천, 제천천하류 등 13개 소유역, TP 관리하천은 주천강시점, 장평천, 주천강상류 등 16개 소유역으로 나타났다. 또한 전체 배출부하에 대한 비점오염원의 배출부하비는 BOD 82.5%, TP 86.2%로 점오염원보다 높았다. 따라서 우선 관리 대상 하천은 TP 비점오염원, BOD 비점오염원, TP 점오염원, BOD 점오염원 순으로 계획될 필요가 있다. 향후 유역 모델링을 수행하고, STL 산정 결과와 비교하여 우심 하천 선정에 대한 적합성을 평가할 예정이다.

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Comparative study of two CAD software programs on consistency between custom abutment design and the output (두 가지 CAD software의 맞춤형 지대주 디자인과 출력물 일치도 비교)

  • Lim, Hyun-Mi;Lee, Kyu-Bok;Lee, Wan-Sun;Son, KeunBaDa
    • Journal of Dental Rehabilitation and Applied Science
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    • v.34 no.3
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    • pp.157-166
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    • 2018
  • Purpose: This study was aimed to compare the consistency between the custom abutment design and the output in two CAD software programs. Materials and Methods: Customized abutments were designed by using 3Shape Dental System CAD software and Delta9 CAD software on a plaster model with implants (CRM STL file). After milling of the designed abutments, the abutments were scanned with a contact method scanner (Test STL file). We overlaid the Test STL file with each CRM STL file by using inspection software, and then compared the milling reproducibility by measuring the output error of the specimens from each CAD software program. Results: The Delta9 showed better milling reproducibility than 3Shape when comparing the milling errors obtained with a full scan of all specimens (P < .05) and also when comparing the axial wall region specifically according to the axial angle. With 0.9 mm marginal radius, the Delta9 showed better consistency between the design and the output than 3Shape (P < .05). While, anti-rotation form had no significant difference in error between the two systems. When cumulative errors were compared, the Delta9 showed better milling reproducibility in almost cases (P < .05). Conclusion: Delta9 showed a significantly smaller error for most of the abutment design options. This means that it is possible to facilitate generation of printouts with reliable reproducibility and high precision with respect to the planned design.

Synergistic antitumor activity of ST1571 and camptothecin in human cancer cells (Camptothecin 에 의한 ST1571 의 항암 활성 증강)

  • Kim, Mi-Ju;Lee, Sang-Min;Bae, Jae-Ho;Chung, Byung-Seon;Kang, Chi-Dug;Kim, Sun-Hee
    • Journal of Life Science
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    • v.17 no.6 s.86
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    • pp.748-755
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    • 2007
  • The in vitro activity of ST1571, an inhibitor of the Abl group of protein-tyrosine kinases, alone or in combination with camptothecin (CPT), a specific topoisomerase I inhibitor, was evaluated against human cancer cells with different metastatic capacity and drug resistance potency. These cell lines showed different sensitivity to ST157 on growth inhibition, and the expression of DNA-dependent protein kinase (DNA-PK), which interacts constitutively with c-Abl, was significantly decreased in drug sensitive CEM and MCF-7 cells and poorly metastatic PC3 and KMl2 cells as compared with that of multidrug resistant CEM/MDR and MCF-7/MDR cells and highly metastatic PC3-MM2 and KM/L4a cells, respectively. These results suggest differential modulation of DNA-PK by ST1571 treatment in drug resistance and metastatic degree dependent manner. We showed that CPT as well as ST1571 significantly inhibits the expression of DNA-PK. The combined treatment with ST15fl and CPT revealed synergistic effect, and the effect was accompanied by inhibition of cell proliferation due to significant reduced expression of DNA-PK components, which resulted in CPT sensitizes human cancer cells resistant to ST1571. Therefore, the results of our study suggested that the suppression of DNA-PK using combination of ST1571 and CPT could be a novel molecular target for against drugresistant and metastatic cancer cells.