• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2002년도 하계종합학술대회 논문집(5)
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• pp.91-94
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• 2002

SFFS(Solid Freeform Fabrication System) is commercializing to rapid prototyping concept in foreign some corporations including the U.S.A, have much technological problems yet and need new mode for agile prototyping. In this paper, we design algorithm that the cutting path of laser beam, on the SFFS(Solid Freeform Fabrication System), is controlled with constant speed. The designed algorithm for constant-speed path control is implemented and experimented in the CAFL$\^$VM/ (Computer Aided Fabrication of Lamination for Various Material) system, the new SFFS which was developed in this paper.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2004년도 추계학술대회 논문집
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• pp.73-77
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• 2004

This paper presents a PC-based controller of industrial SFFS(Solid Freeform Fabrication System). The SFFS has multiple sub-controllers for the building room, the powder room, the temperature, and the density of oxygen in the chambers. Hence the main PC-based controller should effectively and timely send commands to the sub-controllers, and monitor the overall SLS process. The required actuators and sensors are selected to optimize the overall performance of the SFFS.

• 대한기계학회논문집A
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• 제32권7호
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• pp.602-609
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• 2008

This paper presents experimental optimization of process parameters for a newly developed SFF(Solid Freeform Fabrication) system. Two critical process parameters, layering thickness and curing period, which have a large effect on the quality of the product, are optimized through experiments. Specimens are produced using layering thicknesses of 60, 80, 100, 120, 140, and $160\;{\mu}m$ and curing periods of 0, 10, 20, and 30 minutes under the same processing conditions, i.e., build-room temperature, feed-room temperature, roller speed, laser power, scan speed, and scan spacing. The specimens are tested to compare and analyze performance indices such as thickness accuracy, flatness, stress-strain characteristics, and porosity. The experimental result indicates that layering thickness of $80{\sim}100\;{\mu}m$ and curing period of $20{\sim}30$ minutes are recommended for the developed industrial SFF system.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2008년도 추계학술대회A
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• pp.1415-1418
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• 2008

Scaffold fabrication for regenerating functional human tissues has an important role in tissue engineering, and there has been much progress in research on scaffold fabrication. However, current methods are limited by the mechanical properties of existing biodegradable materials and the irregular structures that they produce. Recently, Solid freeform fabrication (SFF) technology was remarked by fabricating 3D free-form micro-structures. Among SFF technologies, we tried to fabricate scaffolds using micro-stereolithography which contain the highest resolution of all SFF technologies and precision deposition system which can use various biomaterials. And we developed the CAD/CAM system to automate the process of scaffold fabrication and fabricate the patient customized scaffolds. These results showed the unlimited possibilities of our SFF technologies in tissue engineering.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회A
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• pp.1400-1403
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• 2007

The 3DP(three dimensional printing) technology is one of the SFF(solid freeform fabrication) technologies which has recently come into a spotlight due to its suitability to various field. A manufacturing process of product is using many pattern formation technology. The 3DP technology uses multi nozzle that can fabricate three dimensional object of high speed and accuracy. In this paper, we introduce a development of the office type solid freeform fabrication system. This system is used UV resin and multi-piezo head.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2002년도 ICCAS
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• pp.91.1-91
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• 2002

1. Introduction Present study presents the basic concept of a Solid Freeform Fabrication System using a rapid prototyping procedure and optimal control for a transferring and accumulating system. And it developed a novel rapid prototyping process that can use ceramic or metal as well as polymer as a basic material. 2. Solid Freeform Fabrication System 2.1 Basic Theory A 3D CAD data of the model is converted to the 2D cross-section data of the slides. A ceramic or metal tape of thickness 0.5-1.5mm is cut by a laser beam with the cross-section data of the slide. A 3D model was obtained by transferring and accumulating the slides. The final product is manufactured by sin...

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 합동 추계학술대회 논문집 정보 및 제어부문
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• pp.75-78
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• 2002

SFFS(Solid Freeform Fabrication System) is commercializing to rapid prototyping concept in world-wide some corporations including the States, have much technological problems yet and need new mode for agile solid freeform fabrication as well as prototyping. In this paper, we design an automatic control algorithm that the cutting path of laser beam, on the SFFS, is controlled with constant speed. The designed algorithm for constant-speed path control is implemented and experimented in the $CAFL^{VM}$ (Computer Aided Fabrication of Lamination for Various Material) system, the new SFFS which is developed in this paper. Its process is an automated fabrication method in which a 3D object is constructed from STL(SToreoLithography) 2D data, derived from CAD 3D image, by sequentially laminating the part cross-sections. The constant-speed path control is started from the STL data. After STL file is modified in data format to be available for control. The fabrication of the 2D part is, with constant speed, conducted from the 23 position data by laser beam. we confirm its high-performance through experiment results from the application into $CAFL^{VM}$ system.

• 한국산학기술학회논문지
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• 제3권4호
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• pp.280-284
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• 2002

본 논문에서는 임의형상제작시스템을 위한 적층 및 이송장치의 컴퓨터 시뮬레이션을 보여주고 있다. 적층 및 이송 장치는 임의형상제작시스템의 필수적인 요소로서 절단된 슬라이스의 일관된 적층을 위해 안정된 작동을 하는 것이 매우 중요하다. 적층 및 이송장치는 공압장치로 모델링될 수 있다. 공압장치는 공압컴푸레서, 제어밸브 및 실린더 둥으로 구성되어있다. 설계변수를 변화시켜가면서 행한 시뮬레이션 결과로부터 시간응답을 예측할 수 있다. 결과에서 알 수 있는 것은 일부 설계변수를 변화시키면 안정된 동특성을 얻을 수 있다는 것이다.

• 대한기계학회논문집A
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• 제30권3호
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• pp.334-341
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• 2006

A solid freeform fabrication (SFF) system using selective laser sintering (SLS) is currently recognized as a leading process and the SLS extends the applications to machinery and automobiles due to various employing materials. In order to fabricate a large part with SFF system, dual laser approach has been introduced. Since the building room is divided into two regions, each scan path for dual laser system is generated based on the single laser scan path. Scan paths for each laser have to be synchronized and consider mechanical strength against fracture at the interfaced region. This paper will address generation of single laser scan path which deals with special cases for unnecessary scan points and generation of dual laser scan path according to various divided regions to enhance mechanical strength. To evaluate the developed scan path method, the specimen will be fabricated and evaluated.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2005년도 ICCAS
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• pp.2164-2169
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• 2005

SFFS(Solid Freeform Fabrication System) can quickly makes models and prototype parts from 3D computer-aided design (CAD) data. Three dimensional printing(3DP) is a kind of the solid freeform fabrication. The 3DP process slices the modeling data into the 50-200um along to z axis. And we pile the powder and make the manufactures. A manufacture is made by the SFFS has the precision of the 50um. Therefore the x-y table of SFFS to move a printhead must be the system that has a high speed and accuracy. So we proposed the SMCSPO algorithm for SFFS. The major contribution is the design of a robust observer for estimating the state and the perturbation of the timing belt system, which is combined with a robust controller. The control performance of the proposed algorithm is compared with PD control by the simulation and the experiment. The control algorithm of the SFFS is presented in the office environment. The system between control system and printhead for the SFFS is also integrated