통합 검색 | Korea Science

정선국;조형석
- Journal of Welding and Joining
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- 제15권3호
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- pp.109-117
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- 1997
The temperature gradient in weldment changes the transit time and distorts the direction of the ultrasound beam to the higher temperature regions due to the lower sound speed in the hotter regions of the weldment. This paper describes a ray-tracing method for calculating the effects of temperature gradients on ultrasonic propagation in fillet arc weldig. In the method, weldment is conceptually devided into a number of layers and the refraction and sound speed at each layer is calculated using the temperature which calculated from analytical solution. Calculating the time and location of echoes arrived from various interfaces around a molten weld pool determines the optimum location of ultrasonic transducers and the correct position of flaws.
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김은미;장호수;박동삼
- 한국생산제조학회지
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- 제19권6호
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- pp.790-796
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- 2010
This paper designed the horn of half-wave needed for Ultrasonic meta) welding. The horn has to be designed and manufactured accurately, because measurements such as the shape, length, mass and etc. have effects on the resonant frequency and the vibration mode. Designed horn of half-wave has the feature of 40,000Hz of nature frequency, and maximizes vibration range in the Tip by resonance in the frequency of ultrasonic wave machine. In this study, we calculated and analyzed the natural frequency to find the optimal design of the horn that amplified the amplitude about double by the modal analysis and harmonic analysis using ANSYS. And we did FFT analysis of the manufactured horn.
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김정호;이지혜;유중돈;최두선
- Journal of Welding and Joining
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- 제21권5호
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- pp.534-539
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- 2003
An efficient soldering process using the longitudinal ultrasonic vibration is introduced in this work for electronic packaging. The effects of the process parameters such as the ultrasonic frequency, amplitude, dimension of the metal bump and solder are analyzed through a viscoelastic lumped model. The viscoelastic properties of the eutectic solder were measured for calculation and evaluation of heat generation capability of the solder. Experiments were conducted to verify the possibility of the proposed ultrasonic soldering method by inserting the Cu and Au bumps into the solder block. Localized heating due to ultrasonic vibration melts the solder near the metal bump, which demonstrates the applicability of the ultrasonic soldering method to the high-density electronic packaging.
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이철구
- Journal of Welding and Joining
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- 제9권1호
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- pp.48-57
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- 1991
Welding of dissimilar materials is an area of growing importance in the automotive, aerospace, electronics medical and other domestic appliance industries. This study investigated the ultrasonic welding of dissimilar polymers. Two amorphous and two semicrystalline polymers were used, utilizing all possible welding combinations. For each combination of dissimilar materials, the weldabilitys of the joint was evaluated as a function of weld time, amplitude of vibration and pressure. The joint was also examined microscopically to analyze the melting and flow of the materials. It was generally around found that welding of amorphus polymers resulted in very poor joints. Welding of the amorphous polymers together and welding of the semicrystalline polymers together produced good joints.
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김창현;유홍연;홍성훈;김재열
- 한국공작기계학회논문집
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- 제16권6호
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- pp.37-42
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- 2007
The purpose of this research is stability estimation of plant structure through classification and recognition about welding flaw in SWP(Spiral Welding Pipe). And, In this research, we used nondestructive test based on ultrasonic test as inspection method, and made up 2-axes inspection robot in order to control of ultrasonic probe on the SWP surface, and programmed to image processing and probabilistic neural network(PNN) classifying code by MATLAB programming. Through this process, we proved efficiency on the system of SWP stability Estimation.
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