• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2010년도 하계학술대회 논문집
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• pp.72-72
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• 2010

The PV module company use variable process step and type. Especially soldering process is important, because crystalline cell can be bow by beating temperature. Most PV module company use hot air soldering type in the tabbing & string process. Although hot air type is used widely but this type is bound to influence on cell damage. So recently new way is introducing like a high current way. In this paper, we compare with characteristics of each soldering type and then conform a method to minimize solar cell deformation. Actually solar cell deformation show many difference by fix position and cooling time after soldering step.

• 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.

• 전력전자학회:학술대회논문집
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• 전력전자학회 1998년도 Proceedings ICPE 98 1998 International Conference on Power Electronics
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• pp.97-100
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• 1998

In this paper, micro step driving method is used for the high performance motion control and low vibration and low noise in an X-Y axis soldering machine for factory automation. The improvement of the electrical and mechanical driving characteristic of a stepping motor is achieved by applying microstep driver.

• 대한치과보철학회지
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• 제8권1호
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• pp.15-19
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• 1968

To compare on the accuracy of bridge made by various soldering technics, four unit bridges were made on a blass original model. They were soldered to each other in the following three ways : In Group I, one central gap between two pieces of pre-soldered abutments and adjacent pontics were soldered at the final step. In Group II, the two gaps between one piece of pre-soldered pontics and two abutments were soldered at the final step. In Group III. the three gaps between two abutments and two ponitcs were soldered at the same time. Misfitting of those bridges were compared by measuring the spaces created between the retainer margins and the shoulders of preparated original model with a micrometer microscope. The author obtained following results : In the final step, the more number of the soldered gap increased, the more accuracy of the bridge decreased.

• 한국산학기술학회논문지
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• 제17권2호
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• pp.325-333
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• 2016

본 연구는 솔더링 시스템에서 세라믹 인두기의 온도 제어를 위한 제어기 설계 알고리즘을 제안하고, 제어 실험으로 그 유효성을 보였다. 솔더링 시스템의 세라믹 인두기 온도 응답 특성이 매우 느리며 제어 입력에 비선형인 특성을 갖고 있어 정밀한 모델링과 제어기 설계에 어렵다. 본 연구에서는 전제부 변수가 제어 입력이고 결론부가 전달함수인 퍼지 규칙들로 구성된 TSK 퍼지 모델로 세라믹 인두기 온도 특성을 표현하였다. 퍼지 모델 결론부의 전달함수는 계단 입력 응답으로부터 구한다. 세라믹 인두기 온도 응답 특성이 매우 느리므로 완전한 계단 입력 응답을 구하기가 어렵다. 불완전한 계단 입력 응답으로 전달함수를 구하는 방법으로 유전적 알고리즘(GA)을 사용하는 것을 제안하며, 예제들로 제안한 그 유효성을 보였다. 또한 TSK 퍼지 모델로부터 퍼지 제어기를 설계하는 방법도 제안하며 그 유효성을 예제 시뮬레이션으로 확인하였다. 제안한 방법들을 세라믹 인두기 온도 제어에 적용하여 실험 하였다. 퍼지 모델의 규칙은 7개로 구성되었으며 퍼지 제어기의 결론부는 PI 제어기로 하였다. 제안한 퍼지 제어기의 실험 결과는 선형 제어기보다 우수하였으며 퍼지 PID 제어기를 사용한 기존 연구 결과에 못지않았다.

• 마이크로전자및패키징학회지
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• 제25권3호
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• pp.13-19
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• 2018

본 연구에서는 태양광 접속함 모듈 적용을 위한 유연 솔더(Sn-Pb) 및 무연 솔더(Sn-3.0Ag-0.5Cu 및 Sn-1.0Ag-0.7Cu-1.6Bi-0.2In)의 특성을 비교 평가하였다. 접속함 내에는 전압 및 전류 검출용 모듈, 고내압용 다이오드가 실장된 정류모듈 등 다양한 모듈이 내장되어있다. 본 연구에서는 솔더링특성, 인쇄성, 솔더형상 검사, X-ray를 이용한 솔더 내 void 검사 및 접합강도를 측정하였고, 무연 솔더 합금의 공정최적화는 step 1과 step 2로 구분하여 검토를 실시하였다. Step 1은 유연 솔더와 무연 솔더 페이스트 인쇄 검사 시험을 1차와 2차로 나누어 실험을 진행하였고 printability는 void 함량 및 접합강도의 상관관계로 검토하였다. 전체적으로 유연 솔더의 특성은 무연 솔더에 비하여 상대적으로 우수하였다. Step 2는 리플로우 공정의 최고점 온도 변화에 따른 접합부 특성 변화를 관찰하였다. 리플로우 최고 온도가 증가할수록 접합부 내의 void 함량이 2~4% 정도 감소하였고, 접합강도는 약 0.5 kgf 범위내에서 큰 차이 없이 나타났다. 기판 표면처리종류에 있어서는 ENIG 표면처리가 OSP 및 Pb-free 솔더 표면처리보다 우수한 접합강도를 나타내었다. 1종류의 무연솔더와 OSP 표면처리로 접합된 태양광 접속함 모듈의 500 싸이클 열충격 신뢰성시험 전후에 전기적 특성변화는 0.3% 내의 범위에서 안정적으로 작동함을 확인하였다.

• The Journal of Advanced Prosthodontics
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• 제6권1호
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• pp.39-45
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• 2014

PURPOSE. The aim of the present study was to evaluate the accuracy of three techniques for correction of cast implant bars. MATERIALS AND METHODS. Thirty cast implant bars were fabricated on a metal master model. All cast implant bars were sectioned at 5 mm from the left gold cylinder using a disk of 0.3 mm thickness, and then each group of ten specimens was corrected by gas-air torch soldering, laser welding, and additional casting technique. Three dimensional evaluation including horizontal, vertical, and twisting measurements was based on measurement and comparison of (1) gap distances of the right abutment replica-gold cylinder interface at buccal, distal, lingual side, (2) changes of bar length, and (3) axis angle changes of the right gold cylinders at the step of the post-correction measurements on the three groups with a contact and non-contact coordinate measuring machine. One-way analysis of variance (ANOVA) and paired t-test were performed at the significance level of 5%. RESULTS. Gap distances of the cast implant bars after correction procedure showed no statistically significant difference among groups. Changes in bar length between pre-casting and post-correction measurement were statistically significance among groups. Axis angle changes of the right gold cylinders were not statistically significance among groups. CONCLUSION. There was no statistical significance among three techniques in horizontal, vertical and axial errors. But, gas-air torch soldering technique showed the most consistent and accurate trend in the correction of implant bar error. However, Laser welding technique, showed a large mean and standard deviation in vertical and twisting measurement and might be technique-sensitive method.

• 한국초전도ㆍ저온공학회논문지
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• 제25권4호
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• pp.28-31
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• 2023

This study presents a comprehensive procedure for the low cycle fatigue test of ultrasonically welded (UW) coated conductor (CC) lap-joints. The entire process is examined in detail, from the robust fabrication of the UW REBCO CC joints to the reliability testing under a low number of repeated cycle fatigue conditions. A continuous I_c measurement system enables real-time monitoring of I_c variations throughout the fatigue tests. The study aims to provide a step-by-step procedure that involves joint fabrication, electromechanical property (EMP) tests under uniaxial tension for stress level determination, and subsequent low-cycle fatigue tests. The joints are fabricated using a hybrid method that combines UW with adding In-Sn soldering, achieving a flux-free hybrid welding approach (UW-HW flux-free). The selected conditions for the low cycle fatigue tests include a stress ratio of R=0.1 and a frequency of 0.02 Hz. The results reveal some insights into the fatigue behavior, irreversible changes, and cumulative damage in the CC joints.

• Applied Microscopy
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• 제45권2호
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• pp.89-94
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• 2015

This article briefly reviews the results of recently reported research on high-temperature Pb-free solder alloys and the research trend for characterization of the interfacial reaction layer. To improve the product reliability of high-temperature Pb-free solder alloys, thorough research is necessary not only to enhance the alloy properties but also to characterize and understand the interfacial reaction occurring during and after the bonding process. Transmission electron microscopy analysis is expected to play an important role in the development of high-temperature solders by providing accurate and reliable data with a high spatial resolution and facilitating understanding of the interfacial reaction at the solder joint.

• 한국태양에너지학회:학술대회논문집
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• 한국태양에너지학회 2009년도 추계학술발표대회 논문집
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• pp.246-250
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• 2009

String & tabbing step in the crystalline PV module manufacturing process for the temperature directly affects solar cells. In fact, in the manufacture of PV modules tend to be temperature factor and the corresponding changes n the output shows the same characteristics. In this journal, it will be considered about thermal characteristics, especially changes of characteristic in high temperature of the solar cell through experiment that we measure electric output characteristics of solar cells after those are applied with high temperature changes for two seconds. And we can think about the possibility of efficiency improvements over looks in PV module manufacturing processes.