• Title/Summary/Keyword: Surface Mount

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Development of Algorithm for Optimal Operation of Surface Mounters (표면실장기의 최적 운영을 위한 모델링 및 알고리듬 개발)

  • Lee, Young-Hae;Kim, Jeong
    • Journal of Korean Institute of Industrial Engineers
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    • v.20 no.3
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    • pp.79-92
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    • 1994
  • Surface mount technology has been evolving in the electronics industries. Efficient operation of surface mounters is closely related with the productivity of the electronic products. In this study, modeling and optimal algorithm for allocating feeders and sequencing mounting jobs in the rotary type surface mounter, which consider all the constraints, in the hardware and are easy to be used in the field, are developed.

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Effect of Multiple Reflows on the Mechanical Reliability of Solder Joint in LED Package (LED 패키지 솔더 접합부의 기계적 신뢰성에 미치는 리플로우 횟수의 영향)

  • Lee, Young-Chul;Kim, Kwang-Seok;Ahn, Ji-Hyuk;Yoon, Jeong-Won;Ko, Min-Kwan;Jung, Seung-Boo
    • Korean Journal of Metals and Materials
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    • v.48 no.11
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    • pp.1035-1040
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    • 2010
  • The research efforts on GaN-based light-emitting diodes (LEDs) keep increasing due to their significant impact on the illumination industry. Surface mount technology (SMT) is widely used to mount the LED packages for practical application. In surface mount soldering both the device body and leads are intentionally heated by a reflow process. We studied on the effects of multiple reflows on microstructural variation and joint strength of the solder joints between the LED package and the substrate. In this study, Pb-free Sn-3.0Ag-0.5Cu solder and a finished pad with organic solderability preservatives (OSP) were employed. A $Cu_6Sn_5$ intermetallic compound (IMC) layer was formed during the multiple reflows, and the thickness of the IMC layerincreased with an increasing number of reflows. The shear force decreased after three reflows. From the observation of the fracture surface after a shear test, partially brittle fractures were observed after five reflows.

A Study on Effect of Pad Design on Assembly and Adhesion Reliability of Surface Mount Technology (SMT) (표면실장기술(SMT)의 조립 및 접합 신뢰성에 대한 패드설계의 영향에 관한 연구)

  • Park, Dong-Woon;Yu, Myeong-Hyeon;Kim, Hak-sung
    • Journal of the Microelectronics and Packaging Society
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    • v.29 no.3
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    • pp.31-35
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    • 2022
  • Recently, with the 4th industrial revolution, the demand for high-density semiconductors for large-capacity data processing is increasing. Researchers are interested in researching the reliability of surface mount technology (SMT). In this study, the effect of PCB pad design on assembly and adhesion reliability of passive component was analyzed using design of experiment (DOE). The DOE method was established using the pad length, width, and distance between pads of the PCB as variables. The assembly defect rate of the passive element after the reflow process was derived according to the misplacement direction of the chip resistor. The shear force between the passive element and the PCB was measured using shear tests. In addition, the shape of the solder according to the pad design was analyzed through cross-sectional analysis.

Variability Analysis of Dynamic Characteristics in Rubber Engine Mounts Considering Temperature Variation (온도변화를 고려한 고무엔진마운트의 동특성 변동성 해석)

  • Hwang, In Seong;Ahn, Tae Soo;Lee, Dooho
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.23 no.6
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    • pp.553-562
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    • 2013
  • Vehicle vibrations arise from engine and road surface excitations. The engine mount system of a passenger car sustains the engine weight and insulates the excitation force from the engine system. The dynamic properties of viscoelastic material used for the vehicle engine mounts have large variation due to environmental factors such as environmental temperature and humidity etc. The present study aims to investigate the variability of dynamic characteristics in rubber engine mounts considering both environmental temperature change and material model errors/uncertainty. The engine mounts for a passenger car were modeled using finite element method. Then, the dynamic stiffness variability of the engine mounts were estimated using Monte Carlo simulation method. In order to estimate the variations in the storage and loss moduli of the viscoelastic materials, the material properties of the synthetic rubber were expressed as a fractional-derivative model. Next, in order to simulate the uncertainty propagation of the dynamic stiffness for the engine mounts due to the storage and loss moduli variations, the Monte Carlo simulation was used. The Monte Carlo simulation results showed large variation of the engine-mount stiffness along frequency axis.

Microstructural and Mechanical Characteristics of Al-Si-Cu Die Casting Alloy for Engine Mount Bracket (엔진 마운트 브라켓용 다이캐스팅 Al-Si-Cu 합금의 미세조직과 기계적 특성)

  • Chyun, In-Bum;Hong, Seung-Pyo;Kim, Chung-Seok
    • Journal of the Korean Society for Heat Treatment
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    • v.27 no.6
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    • pp.281-287
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    • 2014
  • Microstructural and mechanical characteristics of Al-6Si-2Cu alloy for engine mount bracket prepared by gravity casting (as-cast) and die-casting (as-diecast) process have been investigated. For the microstructural characterization, the inductively coupled plasma mass spectrometry (ICP-MS), optical microscope (OM), scanning electron microscope (SEM) and electron probe microanalysis (EPMA) analyses are conducted. For the intermetallic phases, the X-ray diffraction (XRD) and energy dispersive spectroscopy (EDS) are also conducted with quantitative and qualitative analysis. Micro Vickers hardness and static tensile test are achieved in order to measure mechanical properties of alloys. Secondary dendrite arm spacing (SDAS) of as-cast and as-diecast show 37um and 18um, respectively. A large amount of coarsen eutectic Si, $Al_2Cu$ intermetallic phase and Fe-rich phases are identified in the Al-6Si-2Cu alloy. Mechanical properties of gravity casting alloy are much higher than those of die-casting alloy. Especially, yield strength and elongation of gravity casting alloy show 2 times higher than die-casting alloy. After shot peening, shot peening refined the surface grains and Si particles of the alloys by plastic deformation. The surface hardness value shows that shot peening alloy has higher value than unpeening alloy.