• 대한용접접합학회:학술대회논문집
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• 대한용접접합학회 2003년도 추계학술발표대회 개요집
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• pp.159-161
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• 2003

Electrode movement signal has been widely used in resistance spot welding system This study is to compare accelerometer signal with gap sensor signal in servo gun system. This study propose that accelerometer output signal is a useful technique of quality monitoring in resistance welding processes.

• Journal of Welding and Joining
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• 제22권4호
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• pp.12-19
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• 2004

오늘날 IT산업의 괄목할 만한 성장으로 IT관련 휴대장비의 시장은 폭발적으로 증가하고 있다. 전통 제조업분야에서도 IT산업과 메카트로닉스의 발전 덕택에 경량화, 소형화된 전자소자나 전기소자 및 관련 센서, 액츄에이터를 활용할 수 있데 됨에 따라 기계 장비 및 장치가 점점 더 소형화되고 있다.(중략)

• Journal of Welding and Joining
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• 제27권1호
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• pp.102-107
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• 2009

Weldability of Mg alloy was investigated using servo-actuated DC resistance spot welder. Due to its uncommon electrical and mechanical properties, lots of voids and cracks were observed inside nugget with conventional weld schedule. Lobe curve was proposed to clarify proper electrode force and weld current, which guarantee reasonable weld strength and fatigue life. Macro structure of sectioned specimen was examined to count total number of void and crack. Post weld schedule is also proposed to reduce micro victors hardness value of weld zone.

• 전력전자학회논문지
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• 제15권3호
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• pp.218-225
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• 2010

본 논문은 인버터 AC 스폿용접시스템의 용접시간을 최소화하기 위한 방법에 관한 것이다. 기존의 SCR 회로방식을 이용한 스폿용접시스템의 경우 제어속도가 느리고 전류제어가 정밀하지 않다. 따라서 최근에는 인버터를 이용한 용접시스템이 점차 증가하고 있다. 2차전지의 전극과 같은 박판을 용접해야 하는 경우에는 용접시간이 수 [ms] 정도로 짧아야 한다. 수 [ms] 정도로 용접시간을 최소화하면서 수 천 [A]에 달하는 대전류를 흘리기 위해서 일반적으로 수십개의 스위칭 소자들을 병렬로 연결하여 사용하기도 한다. 본 논문에서는 단지 4개의 IGBT로 구성된 인버터와 60[Hz] 변압기만으로 수 [ms] 대의 용접이 가능한 비용절감형 용접시스템을 제안하고 특성을 분석하였다. 그리고 실험을 통하여 타당성과 효용성을 입증하였다.

• 대한용접접합학회:학술대회논문집
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• 대한용접접합학회 2002년도 Proceedings of the International Welding/Joining Conference-Korea
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• pp.187-192
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• 2002

Applicability of laser micro welding process to the fabrication of medical devices was investigated. Austenitic stainless steel wire (SUS304) was spot melted and crosswise welded, which is one of the most possible welding process for the fabrication of medical devices, by using a Nd-YAG laser. Effects of welding parameters on the microstructure, tensile strength and corrosion resistance were discussed. In the spot melting, melted metal width decreased with decreasing the input energy and pulse duration. Controlling the laser wave to reduce laser noise which occurred in the early stage of laser irradiation made reasonable welding condition wider in the welding condition of small pulse duration such as 2ms. The microstructure of the melted metal was a cellular dendrite structure and the cell size of the weld metal was about 0.5~3.5 ${\mu}{\textrm}{m}$. Tensile strength increased with the decrease of the melted metal width and reached to a maximum about 660MPa, which is comparable with that for the tempered base metal. Even by immersion test at 318K for 3600ks in quasi biological environment (0.9% NaCl), microstructure of the melted metal and tensile strength hardly changed from those for as melted material. In the crosswise welding, joints morphologies were classified into 3 types by the melting state of lower wire. Fracture load increased with input energy and melted area of lower wire, and reached to a maximum about 80N. However, when input energy was further increased and lower wire was fully melted, fracture load decreased due to the burn out of weld metal.

• Corrosion Science and Technology
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• 제9권6호
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• pp.331-337
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• 2010

This study compared the macro and micro electrochemical characteristics at the local area of welding metal on dissimilar welding parts for type 304 stainless steel (SS) and type 316L SS. The materials are used for double wall gas pipe of duel fuel engine for a ship. The various potentiodynamic experiments were performed several times in 10% ${H_2C_2O_2}{\cdot}{H_2O}$ solution using macro and micro methods, respectively. The micro electrochemical experiments conducted to resolve at local area on cross-section of dissimilar welding materials by micro-droplet cell device. The micro-droplet cell techniques can be used almost electrochemical experiments to resolve corrosion characteristics of the limited electrode area of the metallic surface between wetted spot of working electrode and tip of sharpened capillary tube. The results of macro electrochemical experiments show that resistance of active dissolution reaction at welding zone was high due to low current density by formation of passivation protection film at passive region. According to the micro electrochemical experiment, the corrosion current density of welding zone and bond zone were relatively high.

• International Journal of Korean Welding Society
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• 제5권1호
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• pp.53-59
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• 2005

Auto industry has employed resistance spot welding(RSW) to join steel sheets for structural rigidity of automobile body. Driven by the need to reduce weight and fuel consumption, car companies have been evaluating aluminum intensive vehicles(AIVs) as a way to reduce vehicle weight without downsizing. During the transition from all steel-construction vehicle body to aluminum intensive body, joining aluminum to steel sheets emerges as a serious contender in automobile body. This paper deals with application of transition material to RSW aluminum to steel. Placing transition material insert between the aluminum/steel interface was found very effective to overcome physical incompatibility between aluminum and steel. Use of transition insert allows for two separate weld nuggets to be formed in their respective aluminum/aluminum and steel/steel interfaces. This RSW processes was monitored with the aid of dynamic resistance sampling. Typical patterns in sampled dynamic resistance curves indicated formation of sound nugget. The growth of two separate nuggets was examined by micro-cross section test.

• 한국레이저가공학회지
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• 제3권2호
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• pp.45-51
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• 2000

In this paper, the possibilities and the limits of the laser seam welding were studied to utilize the advantageous properties of amorphous metal foils. For the conventional welding method, the high heat transfer makes the crystallized zone of the work material unavoidable. The laser is able to weld the amorphous metal without a crystallized zone, because heat transfer is limited within a very small restricted volume. The crystallized zone is restricted in the neighbor of welding spot and not in the melting area. This can be proved directly by the etching and indirectly by the tensile shear test, micro hardness test and bending test. The overlapping of welding bead could form the formation of wider and thicker amorphous zone.

• 대한용접접합학회:학술대회논문집
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• 대한용접접합학회 2004년도 추계학술발표대회 개요집
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• pp.46-48
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• 2004

• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 하계학술대회 논문집 F
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• pp.2578-2580
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• 1999

In this paper, an embedded micro processor based resistance spot welding controller is introduced which has been recently developed by Hyosung Co. Ltd. The performance of rapid and constant high current control is tested experimentally. This paper shows configurations of measuring system for high current and realtime RMS conversion techniques of sampled discrete data. A digital proportional control is adopted for this system and the result shows that this new product is working well at wide range of welding current and the performance is improved compared with some other commercially available controllers that are widely used in our industries. User friendly MMI system and a computer network system to monitor each welding processes are also presented.