• 제목/요약/키워드: SLS(Selective Laser Sintering)

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산업용 SFF 시스템에서 Laser Beam Spot size 측정 메커니즘 개발 (Development of Measurement mechanism of Laser Beam Spot size for Industrial SFF system)

  • 배성우;김동수;최경현
    • 대한기계학회:학술대회논문집
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    • 대한기계학회 2007년도 춘계학술대회A
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    • pp.1383-1388
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    • 2007
  • Accuracy and processing time are very important factors when the desired shape is fabricated with Selective Laser Sintering (SLS), one of Solid Freeform Fabrication (SFF) systems. In a conventional SLS process, laser spot size is fixed during laser exposing on the sliced figure. Therefore, it is difficult to accurately and rapidly fabricate the desired shape. In this paper, to deal with those problems an SFF system having ability of changing spot size is developed. The system provides high accuracy and optimal processing time. Specifically, a variable beam expander is employed to adjust spot size for different figures on a sliced shape. Finally, Design and performance estimation of the SFF system employing a variable beam expander are achieved and the mechanism will be addressed to measure the real spot size generated from the variable beam expander.

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선택적 레이저 소결법을 이용한 기어박스의 정밀주조기술개발 (Development of Precision Casting Technology for Inlet Gear Box using Selective Laser Sintering)

  • 김천기
    • 한국생산제조학회지
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    • 제9권1호
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    • pp.30-37
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    • 2000
  • In this paper rapid prototyping and precision casting technology have been developed for the manufacturing of inlet gear box of an airplane, Rapid prototyping is a new prototyping technology that produces complicated parts directly from three-dimensional CAD data with a high efficiency and has been extensively applied to various manufacturing processes. In the present work Selective Lase Sintering(SLS) system is utilized in order to manufacture prototype of the inlet gear box. Prototyping technology using SLS is also investigated from the viewpoint of accuracy. Using the SLS master the casting products are manufactured through several processes such as : vacuum casting lost wax shell casting and investment cast-ing. The shrinkage characteristics of wax and cast iron in the casting procedures are considered and then reflected to the design procedure so that the accuracy of the product is improved consequently.

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SLS에서의 정밀도 향상을 위한 실험적 연구 (An Experimental Study for Accuracy Enhancement of SLS)

  • 신동훈;전병철;김재도
    • 한국정밀공학회:학술대회논문집
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    • 한국정밀공학회 2000년도 추계학술대회 논문집
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    • pp.943-946
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    • 2000
  • Selective laser sintering(SLS) is a solid freeform fabrication process whereby a part is built layerwise by scanning a powder bed. The properties of metal powder are dependent on the heat, it is not easy to do the exact error compensation with analysis and estimation by modeling. This paper suggests that the error is compensated by experimental method and then the accuracy of shape is enhanced by revising of STL file. Also bonding force is measured by an experiment with change of process path.

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$CO_2$ Laser에 의한 Polyamide-6 소결과 그 영향에 관한 연구 (A Study on Polyamide-6 Sintering and Effect by $CO_2$ Laser)

  • 배성우;김동수;안영진;김형일;최기섭
    • 한국정밀공학회:학술대회논문집
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    • 한국정밀공학회 2006년도 춘계학술대회 논문집
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    • pp.197-198
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    • 2006
  • In the solid freeform fabrication (SFF) system using selective laser sintering (SLS), polyamide-12 powder is currently recognized as general material. In this study, some kinds of polyamide-6 powders with different shape and particlesize were fabricated to investigate the formability, the microstructure and mechanical properties. Also, to develop a more elaborate and rapid system, this study employs a new SLS device with a 3-axis dynamic focusing scanner system instead of the existing fe lens used in commercial SLS. Polyamide-6 powders having the average size of 100 m were treated thermally in order to keep the spherical symmetry in shape. These polyamide-6 powders were mixed with polyamide-12 powders having the average size of 50 m to give the bimodal distribution of size. These mixed powders showed the better fabrication in the selective laser sintering process because the smaller particles of polyamide-11 played an important role in the compact packing of powders by filling the void space between the large particles of polyamide-6. Also, Experiments have performed to evaluate the effect of a scanning path and sintering parameters by fabricating the various 3D objects.

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SLS에 의한 PCL/TCP 복합체 제작공정변수의 최적화 (Processing Optimization of PCL/TCP Composites Produced by Selective Laser Sintering)

  • 정하승;지해성
    • 한국CDE학회논문집
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    • 제13권6호
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    • pp.421-428
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    • 2008
  • This article investigates the fabrication of polycaprolactone (PCL) composites filled with different volume fractions (10-30%) of tricalcium phosphate (TCP) by selective laser sintering (SLS) for tissue engineering scaffolds. Optimal processing parameters for each composition were developed by design of experiments (DOE). Specimens for compressive testing for each composition were fabricated and tested. The results showed that the compressive modulus increases as a function of TCP volume fraction. The experimentally measured compressive moduli were compared with moduli predicted by Halpin's theoretical model and were found to be in excellent agreement. This result proved that experimentally determined processing parameters for each composition were well optimized.

레이저선택용융기술에 의해 제작된 금속 코어의 변연 적합도 분석 (An analysis of marginal adaptation of metal cores fabricated by selective laser sintering)

  • 김원수;김기백
    • 대한치과기공학회지
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    • 제38권4호
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    • pp.305-311
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    • 2016
  • Purpose: The purpose of this study were to analysis of marginal adaptation of metal cores fabricated by selective laser sintering. Methods: Main model was prepared and ten stone models were fabricated. Ten single metal cores were fabricated by selective laser sintering(SLS group) and another ten single metal cores using lost wax technique and casting method were manufactured(CAST group). The marginal adaptation of metal cores were analysis using by the silicone replica technique. Silicone replicas were sectioned two times. The marginal adaptations were measured using by digital microscope. Statistical analyses was performed with independent t-test(${\bullet}{\cdot}=0.05$). Results: Means of marginal adaptations were 90.3 ${\ss}{\uparrow}$ for SLS group and 65.1 ${\ss}{\uparrow}$ for CAST group. Two groups were statistically significant differences (p < 0.05). Conclusion: Marginal adaptation of metal cores fabricated by selective laser sintering were ranged within the clinical recommendation.

다구찌 방법을 이용한 SLS 조형품의 치수정밀도 향상에 관한 연구 (A Study on Improvement on Dimensional Accuracy of SLS parts using Taguchi Method)

  • 황보중;양화준;이석희
    • 대한기계학회:학술대회논문집
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    • 대한기계학회 2000년도 춘계학술대회논문집A
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    • pp.860-865
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    • 2000
  • This Paper Proposes the test pieces of X, Y and Z axes to compensate the shape distortion of Selective Laser Sintering(SLS) parts resulting from the phase change during the sintering process. In no case of the proposed compensation test pieces of X, Y axes the accurate rates of shrinkage can be measured with the reduction of curling which is obtained from adjustment of build orientation and the formula used to get scale factors are proposed with the shrinkage rates of them. The scale factors of X, Y and Z axes are generated by building up proposed compensation test pieces. The generated scale iactors are required to satisfy the dimensional accuracy even if there are changes of the build position and the size of SLS parts in the build chamber. For this reason, it is proposed that the build positions and the size be considered to be noise factors against the compensation test pieces and a method is also proposed that scale factors be selected to robustly maintain the dimensional accuracy of SLS parts under the actual operating conditions with the application of the Taguchi Method.

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