• Title/Summary/Keyword: STL

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Rapid Prototyping from Reverse Engineered Geometric Data (리버스 엔지니어링으로 생성된 데이터를 이용한 쾌속 조형 기술 연구)

  • Woo, Hyuck-Je;Lee, Kwan-Heng
    • Journal of the Korean Society for Precision Engineering
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    • v.16 no.1
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    • pp.95-107
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    • 1999
  • The design models of a new product in general are created using clay models or wooden mock-ups. The reverse engineering(RE) technology enables us to quickly create the CAD model of the new product by capturing the surface of the model using laser digitizers or coordinate measuring machines. Rapid prototyping (RP) is another technology that can reduce the product development time by fabricating the physical prototype of a part using a layered manufacturing technique. In reverse engineering process, however, the digitizer generates an enormous amount of point data, and it is time consuming and also inefficient to create surfaces out of these data. In addition, the surfacing operation takes a great deal of time and skill and becomes a bottleneck. In rapid prototyping, a faceted model called STL file has been the industry standard for providing the CAD input to RP machines. It approximates the CAD model of a part using many planar triangular patches and has drawbacks. A novel procedure that overcomes these problems and integrates RE with RP is proposed. Algorithms that drastically reduce the point clouds data have been developed. These methods will facilitate the use of reverse engineered geometric data for rapid prototyping, and thereby will contribute in reducing the product development time.

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RP Preprocessor Based on Distributed Objects (분산객체를 응용한 RP Preprocessor의 기능 구현)

  • 지해성;이승원
    • Journal of the Korean Society for Precision Engineering
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    • v.20 no.2
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    • pp.120-128
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    • 2003
  • When considering the use of rapid prototyping (RP), there are many issues a designer has to address for handling an STL model, the de facto standard fur RP. Today designers can skip all these issues by visiting web-based service bureaus that readily supply needed information for the RP services. Since orders are taken for RP parts through the web page of service providers designers are now asked to upload their STL files to the company server either by direct upload, ftp file transfer, or as an e-mail attachment. If the service bureau, however, fixes or edits an STL filceto optimize the RP process but neglects to tell its customer about the rework in detail, it may cause problems down the line in processing of the original CAD data for other applications. In this paper, we propose a framework for a collaborative virtual environment between CAD designers and RP processes on the internet which directly provides designers with an advanced preprocessor functionality, design visualization, as well as model display, repair, and slicing over the network. This can help smooth data transfer from CAD to RP process with minimum inconsistency in CAD.

Comparison of Sound Transmission through Single and Double-layer Polymer Panels (폴리머계 단일 및 이중구조 방음패널의 차음특성 비교분석)

  • Kim, Il-Ho;Lee, Ju Haeng;Son, Jin-Hee
    • Journal of Korean Society of Environmental Engineers
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    • v.36 no.9
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    • pp.597-603
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    • 2014
  • The aim of the present study is to compare sound performance depending on thickness, materials, and structure of polymer soundproof panels consisting of PC, PMMA, HDPE, and PP, respectively. As a result of comparing sound transmission loss (STL) of single layer panel made of four types of polymer, the better sound transmission loss was obtained in order of PC, PMMA, HDPE, and PP, which was obviously followed mass law. 8 mm of single panel showed 5~6 dB(A) greater STL than that of 4 mm panels and lower frequency for coincidence effect so that STL of 8 mm panels decreased around 4,000~5,000 Hz, indicating less STL of 4 mm panels than those of 8 mm. When it comes to structure, 4 mm panels with air layer appeared similar value of STL with 8 mm single panels under 300 Hz. In range of high frequency above 2,000 Hz, 4 mm panels with air layer performed better than 8 mm of single layer panel while resonance effects were observed at 500~630 Hz. It was found that these results could be practically utilized as fundamental data for noise barriers design considering the change to each condition.

Effect of the STereoLithography File Structure on the Ear Shell Production for Hearing Aids According to DICOM Images (DICOM 영상에 의한 STL 파일 구조가 보청기 이어 쉘 제작에 미치는 영향)

  • Kim, Hyeong-Gyun
    • Journal of radiological science and technology
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    • v.40 no.1
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    • pp.121-126
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    • 2017
  • A technique for producing the ear shell for a hearing aid using DICOM (Digital Imaging and Communication in Medicine) image and a 3D printing was studied. It is a new application method, and is an application technique that can improve the safety and infection of hearing aid users and can reduce the production time and process stages. In this study, the effects on the shape surface were examined before and after the printing of the ear shell using a 3D printer based on the values obtained from the raw data of the DICOM images at the volumes of 0.5 mm, 1.0 mm, and 2.0 mm, respectively. Before the printing, relative relationship was compared with respect to the STL (STereoLithography) file structure; and after the printing, the intervals of the layered structure of the ear shell shape surface were compared by magnifying them using a microscope. For the STL file structure, the numbers of triangular vertices, more than five intersecting points, and maximum intersecting points were large in the order of 0.5 mm, 1.0 mm, and 2.0 mm, respectively; and the triangular structure was densely distributed in the order of the bending, angle, and crest regions depending on the sinuosity of the external auditory meatus shape. As for the ear shell shape surface examined by the digital microscope, the interval of the layered structure was thick in the order of 2.0 mm, 1.0 mm, and 0.5 mm. For the STL surface structure mentioned above, the intersecting STL triangular structure was denser as the sinuosity of the 3D ear shell shape became more irregular and the volume of the raw data decreased.

Assessment of the Effects of Interactions between Climatic Conditions and Genetic Characteristics on the Agronomic Traits of Soybeans Grown in Six Different Experimental Fields

  • Park, Myoung Ryoul;Cai, Chunmei;Seo, Min-Jung;Yun, Hong-Tae;Park, Soo-Kwon;Choi, Man-Soo;Park, Chang-Hwan;Moon, Jung Kyung
    • KOREAN JOURNAL OF CROP SCIENCE
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    • v.64 no.3
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    • pp.246-268
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    • 2019
  • Soybean [Glycine max (L.) Merr.] is a species of legume native to East Asia. The interactions between climatic conditions and genetic characteristics are known to affect the agricultural performance of soybean. Therefore, the present investigation was conducted to identify the main elements affecting the agricultural performances of 11 soybean varieties/lines from China [Harbin ($45^{\circ}12^{\prime}N$), Yanji ($42^{\circ}53^{\prime}N$), Dalian ($39^{\circ}30^{\prime}N$), Qingdao ($36^{\circ}26^{\prime}N$)] and the Republic of Korea [Suwon ($37^{\circ}16^{\prime}N$), and Jeonju ($35^{\circ}49^{\prime}N$)]. The days to flowering (DTF) of soybeans with the e1-nf and e1-as alleles and the E1e2e3e4 genotype, except in 'Keumgangkong', 'Tawonkong', and 'Duyoukong', were relatively short compared to those of soybeans with other alleles. Although DTF of the soybeans was highly correlated with all climatic conditions [negative: precipitation, average temperature (AVT), accumulated temperature; positive: day-length (DL)], days to maturity and 100-seed weight of the soybeans showed no significant correlation with any climatic conditions. The soybeans with a dominant Dt1 allele, except 'Tawonkong', had the longest stem length (STL). Moreover, STL of the soybeans grown in the test fields showed a positive correlation with only DL; however, the results of our chamber test that was conducted to complement the field tests showed that STL of soybean was positively affected by AVT and DL. Although soybean yield (YLD) showed positive correlations with latitude and DL (except L62-667, OT89-5, and OT89-6), the response of YLD to the climatic conditions was cultivar-specific. Our results show that DTF and STL of soybeans grown in six different latitudes are highly affected by DL, and AVT and genetic characteristic also affect DTF and STL.

Broadcast Gateway for ATSC 3.0 Single Frequency Network (ATSC 3.0 단일주파수망을 위한 방송 게이트웨이 기술)

  • Kim, Soonchoul;Lim, Bomi;Kim, Heung Mook;Shin, Gunsoo
    • Proceedings of the Korean Society of Broadcast Engineers Conference
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    • pp.137-138
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    • 2017
  • ATSC 3.0 방송게이트웨이는 원격의 송신소에 설치된 다수의 송신기들(transmitters)과의 안정된 통신 링크(광케이블, M/W, 위성 등)을 통해 방송 미디어 패킷 스트림을 내보낸다. ATSC 3.0 표준에서는 방송 게이트웨이와 송신기 간 STL (Studio to Transmitter Link) 구간에 STLTP (STL Transport Protocol)를 정의하고, 멀티캐스트 구조 내에 IP 터널링(Tunneling) 형태로서 BB 프레임과 L1 시그널링 정보, 시간 정보를 싣도록 한다. 본 논문에서는 ATSC 3.0 기반의 방송 게이트웨이의 주요 기능 역할로서 단일주파수망(SFN)을 위한 패킷 스트림 구성 및 이를 위한 기능 구조에 대해 기술한다.

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Sound Insulation Performance of the Multi-layered Window Structures for the Express Trains (고속철도 차량용 다층 유리창 구조의 차음성능)

  • Lee, Ho-Jin;Lee, Jung-Hyeok;Park, In-Seok;Kim, Seock-Hyun
    • Proceedings of the KSR Conference
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    • pp.2256-2262
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    • 2011
  • In this study, sound transmission loss (STL) is investigated on the multi-layered windows used in the KTX-sancheon and next generation HEMU-400x high speed train. Using TLOSS, which is developed as a special purpose STL analysis program, STLs of the multi-layered glass windows are analytically investigated and compared with the mass law result. Window specimens for the two train models are manufactured and intensity transmission losses are measured based on ASTM E2249-02. The problems in aspect of sound insulation are diagnosed on the two window models. The aim of this study is to provide useful data for the improvement of the interior noise in the high speed train.

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