• Current Photovoltaic Research
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• 제4권2호
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• pp.59-63
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• 2016

A key point of a soldering process for photovoltaic (PV) modules is to increase an adhesive strength leading a low resistivity between ribbon and cell. In this study, we intended to optimize a heating condition for the soldering process and characterize the soldered joint via physical and chemical analysis methods. For the purpose, the heating conditions were adjusted by IR lamp power, heating time and hot plate temperature for preheating a cell. Since then the peel test for the ribbon and cell was conducted, consequently the peel strength data shows that there is some optimum soldering condition. In here, we observed that the peel strength was modified by increasing the heating condition. Such a soldering property is affected by a various factors of which the soldered joint, flux and bus bar of the cell are changed on the heating condition. Therefore, we tried to reveal causes determining the soldering property through analyzing the soldered interface.

• 대한치과기공학회지
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• 제30권1호
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• pp.49-55
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• 2008

In this study, to provide the fundamental data on stable connection method for successful implants prosthesis, We fabricated the solder joint of gold alloy bar specimens by gas flame soldering method and laser welding and soldering method. It compared and studied the tensile strength of two soldering method by universal testing machine. The results using universal testing machine were as follow : The mean of tensile strength of solder joint bar in gas flame soldering method specimens was 363.89 $\pm$17.62 MPa, and the mean strength of laser welding and soldering method was 125.91 $\pm$ 19.66 MPa, so gas flame soldering method was better than laser welding and soldering method and the finding better way to improve tensile strength is needed in laser welding method. On weak loading condition and the part which is needed an accuracy, laser welding method is more effective and on long-span prosthesis and frequent chewing loading part, laser welding technique is recommended first and applying additional gas flame soldering technique would be better for making much more successful prosthesis.

• International Journal of Clinical Preventive Dentistry
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• 제14권4호
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• pp.247-255
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• 2018

Objective: Osseointegration is essential process for successful implants and effects to implant in long term, therefore, passive fitness of good prosthesis is necessary. To make a good prosthesis, at first it should be done a sectioned casting and then joined method of sectioned casting body is recommended. Methods: In this study, to provide the fundamental data on stable connection method for successful implants, the author tested fitness of casting body, and compared difference between gas soldering technique and laser welding technique. Results: In fitness test of 2 abutment (test A, C), gas soldering group's fitness in the opposite part of connection was worse than laser welding group. In fitness test of 3 abutment (test B, D), gap distance was increased both in gas soldering technique and laser welding technique. Gap distance at the connecting part and the opposite part of the abutment in gas soldering technique was worse than laser welding technique and the more additional abutment, the worse gap distance in gas soldering technique. In fitness test of 3 abutment (test B, D), there's little variation in No. 2 abutment when connecting soldering process was done and there's little influence on already soldered connection part when the additional soldering connection was done. Conclusion: On weak loading condition and the part which is needed an accuracy, laser welding technique is more effective and on long-span prosthesis and frequent chewing loading part, laser welding technique is recommended first and applying additional gas soldering technique would be better for making much more successful prosthesis.

• Journal of Welding and Joining
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• 제22권1호
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• pp.65-70
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• 2004

A soldering process with longitudinal ultrasonic is conducted in this work using the Au bump and substrate. Localized heating of the solder is achieved and the stirring action due to the ultrasonic is found to influence the bond strength and microstructure of the eutectic solder The acceptable bonding condition is determined from the tensile strength. Since the multiple bonds can be formed simultaneously with localized heating, the proposed ultrasonic soldering method appears to be applicable to the high-density electronic package.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 하계학술대회 논문집 B
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• pp.1365-1367
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• 2003

In this paper, element technologies such as soldering. arrangement and lamination processes for photovoltaic module manufacture were examined and described as main processes. Especially solder paste and temperature condition in soldering process, loss factor in arrangement process and process conditions in lamination process are investigated to minimize the electrical loss. As a results, temperature condition in soldering process was found to be critical to contact resistance of electrode and life-time. Productivity of the process decreases dramatically by physical damage during arrangement process. Pressure level and press condition of upper chamber in lamination process were important parameters for the reliability. According to the test result of photovoltaic module, electrical properties dropped about $5{\sim}25%$ after 5 years.

• Journal of Welding and Joining
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• 제16권5호
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• pp.100-107
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• 1998

This paper describes fluxless soldering of reflow soldering process using solder foil instead of solder pastes. There is an increasing demand for the reliable solder connection in the recent high density microelectronic components technologies. And also, it is problem fracture of an Ozone layer due to freon as which is used to removal of remained flux on the substrate. This paper discussed joining phenomena, boudability and joining processes of microelectronics devices, such as between outer lead of VLSI package and copper pad on a substrate without flux. The shear strength of joints is 8 to 13 N using Sn/Pb (63/37 wt.%) solder foil with optimum joining conditions, meanwhile, in case of using Sn/In (52/48 wt.%) solder foil, it is possible to bond with low heating temperature of 550 K, and accomplish to high bonding strength of 25N in condition heating temperature of 650K. Finally, this paper experimentally shows fluxless soldering using solder foil, and accomplishes key technology of microsoldering processes.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2000년도 춘계학술대회논문집 - 한국공작기계학회
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• pp.153-158
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• 2000

This paper addresses an intelligent robot control system using an off-line programming to teach a precise assembly task of electronic components in a flexible way. The investigated task consists of three job: heat caulking test, soldering on a circuit board, and checking of soldering defects on the back cover of a camera. This study investigates the remodelling of the most complicated cell in terms of the accuracy and fault rate among the twelve cells in a camera back-cover assembly line. We have attempted to enhance back-cover assembly line. We have attempted to enhance soldering quality, to add task flexibility, to reduce failure rate, and to increase product reliability. This study modifies the cell structure, and improves the soldering condition. The developed all system implements the real-time control of assembly with vision data, and realized an easier task teaching on off-line programming.

• 마이크로전자및패키징학회지
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• 제7권3호
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• pp.55-61
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• 2000

직경 0.3 mm의 Sn-37Pb 및 Sn-3.5Ag-0.7Cu 솔더볼을 솔더링 온도와 기판의 이송속도 (conveyer speed)를 변화시켜 가며 리플로 솔더링 하였다. 리플로 솔더링 온도범위는 Sn-37Pb의 경우 220~$240^{\circ}C$, Sn-3.5Ag-0.7Cu의 경우는 230~ $260^{\circ}C$로 하였다. 실험결과, 전단강도 측면에서 최적 솔더링 조건을 Sn-37Pb의 경우 솔더링 온도 및 컨베이어 속도가 각각 $230^{\circ}C$, 0.7~0.8 m/min이고, Sn-3.5Ag-0.7Cu의 경우 각각 $250^{\circ}C$, 0.6 m/min으로 나타났다. 또한 최고 전단강도 값은 Sn-37Pb의 경우는 555 gf 이고 Sn-3.5Ag-0.7Cu의 경우는 617gf이다. 접합계면의 분석결과 Cu6Sn5층의 두께는 Sn-37Pb의 경우는 1.13~1.45 $\mu\textrm{m}$이고 Sn-3.5Ag-0.7Cu의 경우는 2.5~4.3 $\mu\textrm{m}$이다.

• 전력전자학회:학술대회논문집
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• 전력전자학회 1997년도 전력전자학술대회 논문집
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• pp.318-321
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• 1997

This paper is about improving characteristic of plant by using micro-step driver method in 5 phase step motor for satisfying the condition of low oscillation and high accuracy in soldering machine. We choose open loop control method for minimizing hardware system and use one chip microprocessor, power MOSFET nd some device to realize accurate micro-step driver system.

• 대한치과보철학회지
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• 제37권6호
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• pp.730-740
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• 1999

The purpose of this study was to investigate setting and thermal expansion of dental soldering investments. In order to compare expansion rates and to investigate the effect of water/powder ratio on expansion, setting and thermal expansion of low dental soldering investments were measured under three different water/powder ratio conditions. standard, 20% decreased and 20% increased. Setting expansion of investments was measured by use of dialgauge method. Each measurement was started two minutes later from the beginning of spatulation and recorded every one minute for one hour. Thermal expansion of cylindrical test specimens, 10mm diameter, 50mm length, was recorded in a thermodilatometer at heating rate of $10^{\circ}C$ per minute from $25^{\circ}C\;to\;700^{\circ}C$. The results of this study were obtained as follows: 1. Setting expansion rates under the standard water/powder ratio condition were 0.198% in Speed-E, 0.090% in Deguvest, 0.080% in CM and Hi-temp. Setting expansion of Speed-E was significantly different from those of CM, Deguvest and Hi-temp, and setting expansion of Deguvest was significantly different from those of CM and Hi-temp(p<.05). 2. Under the decreased water/powder ratio condition, there was significant increase in setting expansion of 4 dental soldering investments (p<.05). 3. There were no significant differences in setting expansions of investments except Hi-temp between standard and increased water/powder ratio condition(p<.05). 4. Thermal expansion rates under the standard water/powder ratio condition were 1.923% in Deguvest, 1.629% in Speed-E, 1.619% in Hi-temp and 1.580% in CM. No significant differences in thermal expansions under the standard water/powder ratio condition existed only between Speed-I and Hi-temp(p<.05) 5. Under the decreased water/powder ratio condition, there was significant increase in thermal expansion of CM and Deguvest but decrease in thermal expansion of Speed-E (p<.05). 6. Under the increased water/powder ratio condition, there was significant decrease in thermal expansion of CM, Deguvest and Speed-I but decrease in thermal expansion of Hi-temp(p<.05).