• 제목/요약/키워드: DC Resistance Welding

검색결과 27건 처리시간 0.018초

유전알고리즘을 이용한 인버터 DC 저항점용접에서의 정전류퍼지제어기 최적화 (Optimization of Fuzzy Controller for Constant Current of Inverter DC Resistance Spot Welding Using Genetic Algorithm)

  • 유지영;윤상만;이세헌
    • Journal of Welding and Joining
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    • 제28권5호
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    • pp.99-105
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    • 2010
  • Inverter DC resistance spot welding process has been very widely used for joining such as automotive body sheet metal. Because the lobe area of DC welding is larger than AC welding and DC welding has low electrode wear. So the use of Inverter DC resistance spot welding process has been further increased. And the application of high tensile steel is growing for light weight vehicle. To improve the weldability of high strength steel, the development of Inverter DC resistance spot welding system is more conducted. However, Inverter DC resistance spot welding system has a few problems. Current waveform is unstable and the expulsion has been occurred by characteristics of steel. In this study, inverter DC resistance spot welding system was made. And Fuzzy control algorithm was applied for constant current. The genetic algorithm was applied to optimize the fuzzy scaling factors, in order to optimize the fuzzy control.

DP60강의 인버터 DC 저항 용접의 용접 특성 및 기계적 성질에 관한 연구 (The Study on Inverter DC Resistance Spot Welding Character & Mechanical Property of DP60 Steels)

  • 김인주
    • 한국산학기술학회:학술대회논문집
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    • 한국산학기술학회 2011년도 추계학술논문집 2부
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    • pp.604-606
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    • 2011
  • Purpose This study analyzes resistance spot weldability of DP60 steels. Methodology To compare the resistance spot weldability of DP60 steels, tensile strength test and macro-section test were conducted for the resistance spot welds. Acceptable welding conditions were determined as a function of the resistance spot welding process parameters such as electrode force, welding time, and welding current. The lower limit of the welding lobe was the minimum shear tension strength for 590MPa-grade steel while the upper limit was determined whether or not expulsion was detected. Findings Welding force is 200kgf more appropriate in terms of 300kgf the larger the width of the welding zone. Acceptable welding current condition and welding lobe were changed depending on welding force. Research limitations This study is forced on inverter DC resistance spot weldability of 590Mpa-grade steels for automotive application. Practical implications This study confirms the weldability of DP60 steel by comparing resistance spot weldability depending on welding force. Originality This study analysed resistance spot weldability depending on welding force. wedability of DP60 steel were determined by welding lobes.

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DC 인버터 저항 스폿 용접에서 후전류 효과에 관한 연구 (A Study of Post-current Effect in DC Inverter Resistance Spot Welding)

  • 이희준;이세헌
    • 한국생산제조학회지
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    • 제18권6호
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    • pp.598-603
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    • 2009
  • Resistance spot welding has been investigated to apply for manufacturing car bodies because of its high productivity. So quality of resistance spot weld is one of the major concerns for both automobile and aerospace industry. Current design trends in automotive manufacture have shifted emphasis to alternative lightweight materials in order to aid in producing vehicles with higher fuel efficiency and lower down the vehicle emission level for environmental control. There is increasing emphasis to provide lighter cars. Therefore there is an effort to use high strength steels such as HSLA, dual phase, in car body. However there is used in restricted because of difficulty in producing consistently high quality resistance spot welds. In this study, resistance spot welding schedules were developed to achieve acceptable welds with improved static mechanical properties. Improved resistance spot welding schedules were developed using post heating current to reduce the cooling rate, or in-process tempering to reduce the hardness of the weld produced. The effects of resistance spot welding process parameter on hardening fracture mode and static mechanical properties of the joints were determined.

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DP 590 GA 강재의 압흔형상과 동저항을 이용한 인버터 DC 용접기의 통계적 품질평가 (A Statistical Quality Evaluation Using Indentation Geometry and Dynamic Resistance Of Inverter DC Resistance Spot Welding)

  • 안주선;김재성;이보영;은종목;김동철
    • 대한용접접합학회:학술대회논문집
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    • 대한용접접합학회 2009년 추계학술발표대회
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    • pp.68-68
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    • 2009
  • 최근에 자동차 차체 경량화를 목적으로 개발된 고장력강의 용접품질 향상을 위해 인버터 DC 점용접기가 많이 사용되어지고 있다. 본 연구에서는 국내에서 개발된 인버터 DC 용접기를 사용하여 자동차용 590MPa 고장력 냉연강판(CR, SPFC 590RA)과 아연 도금 강판 (GA- EZFFC 590RA)의 용접품질을 평가하였다. 용접에 사용된 기본 조건은 인장 전단 시험을 통하여 결정하였으며, 동저항, 압흔 자국과 너겟 지름, 인장강도와의 관계를 통계적 방법으로 분석하였으며, 이를 활용하여 고장력 강판의 동저항과 압흔 자국에 따라 너겟 지름과 용접강도를 예측하는 비파괴적 용접 품질 평가 방법을 제시하였다.

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전기아연 도금 TRIP강판의 저항 점용접 시 연속타점 수명에 미치는 단상 AC와 인버터 DC의 비교 연구 (A Comparative Study of Single-Phase AC and Inverter DC on Electrode Life for Resistance Spot Welded Electrogalvanized Steel Sheets)

  • 손종우;박영도;강문진;김동철
    • 대한금속재료학회지
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    • 제47권12호
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    • pp.834-841
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    • 2009
  • A study on the welding of electrogalvanized TRIP (Transformation-Induced Plasticity) steels was done to compare the life of the electrode and the alloying phenomena on the electrode tip surface using singlephase AC and inverter-DC resistance welding processes. A longer life of the electrode (>200 welds) was achieved using the inverter-DC welding process. The tensile shear strength was higher in the electrode life test when welded with the inverter DC welding machine it maintained a higher value even when the welding nugget diameter was smaller than specified. When spot-welding was conducted using the single-phase AC welding process, a higher wear rate of the electrode was observed compared to that with the inverter-DC process. An alloying layer used to determine the rate of electrode growth showed differences in the metallurgical features of the surface alloying and Zn penetration depending on whether the single-phase AC process or the inverter-DC welding process was used. Moreover, changes in the dynamic resistance during the electrode life test were correlated with the electrode wear (or growth) rate.

인버터 DC 저항점용접 공정에서 CRS 알고리즘을 이용한 정전류 퍼지 제어시스템 설계에 관한 연구 (Study of the Constant Current Fuzzy Control System Design using CRS Algorithm during Inverter DC Resistance Spot Welding Process)

  • 박형진;박평원;유지영;김동철;강문진;이세헌
    • Journal of Welding and Joining
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    • 제28권6호
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    • pp.76-83
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    • 2010
  • The purpose of this study is to propose a method to decide near-optimal settings of the constant current fuzzy control parameters using a controlled random search. This method tries to find the near-optimal settings of the constant current fuzzy control parameters through experiments. It has an advantage of being able to carry out searches in the search domain which includes some irregular points. The method suggested in this study was used to determine the fuzzy control parameters by which the desired welding current were formed during inverter DC resistance spot welding. The output variable was the ITAE (integral of time multiplied by the absolute error). This output variable was determined according to the input variables, which are the GE, GDE, and GDU. This study described how to obtained near-optimal welding current condition over a wide search space conducting a relatively small number of experiments.

정밀저항시리즈 점용접에서 너깃의 대칭성에 미치는 공정변수의 영향 (The Effect of Process Parameter on the Symmetry of Nugget in Micro-resistance Series Spot Welding)

  • 조상명;김송미
    • Journal of Welding and Joining
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    • 제19권6호
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    • pp.622-629
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    • 2001
  • The aim of this experiment is to establish the method that obtains symmetrically two nuggets in microresistance series spot welding. The sheets of austenite stainless steel STS304 applied to various electronic parts were experimented by the inverter welding power source of polarity controllable type and by the twin head for left and right electrode force to be controlled separately. The experimental results were obtained as follows : 1) When series spot welding was carried out by DC 1 pulse as welding current with same electrode force at left and right, the asymmetry of nuggets was resulted from the larger nugget of the (-) pole because of the Peltier effect. The dynamic resistance of weld spot at left and right was appeared differently according to the growth of nuggets. 2) When AC 1 cycle by welding power source of polarity controllable type was applied, the nuggets were almost symmetrically formed. 3) In a twin head, if the electrode force of (-) pole was larger than that of (+) pole, the diameters of two nuggets became to same. It was confirmed that the dynamic resistance of (-) pole was decreased to the same level as it of (+) pole. 4) Although the forces of left and right electrode were same, and only DC 1 pulse was applied, symmetric nuggets were obtained if the conductivity of (+) pole was lower than it of (-) pole.

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원통 실린더의 기밀을 위한 서보가압식 DC 프로젝션용접 (Servo-actuate DC Projection Welding of Cylinder for Vacuum Airtightness)

  • 정선녀;장희석
    • 대한용접접합학회:학술대회논문집
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    • 대한용접접합학회 2010년도 춘계학술발표대회 초록집
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    • pp.48-48
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    • 2010
  • 소형 공조장치용 냉매 압축기 부품인 기계식 제어 밸브는 에어컨 컴프레서의 핵심부품이고 년간 수백만 개가 국내에 수입된다. 이를 국산화 하기 위하여 진공로 속에서의 브레이징 공정이 수반되는 외국제품의 제조공정을 탈피하여 진공 속에서 DC 프로젝션 용접을 수행하는 기법을 개발하였다. 실린더 형상의 캡과 케이스를 맞대고 그 사이에 박판을 삽입한 상태에서 butt welding 방식으로 진행되는 본 공정에서는, 생산성이 높고 서보가압 장치를 사용하여 soft touch 를 구현하므로 프로젝션이 손상되지 않은 상태에서 통전이 시작되고 2 단 가압 및 프로파일 가압이 가능하므로 링(ring)형상의 너깃이 축대칭으로 안정적으로 형성되기 때문에 실린더 내부의 밀봉성능이 우수함을 확인하였다. 진공로 속에서 본 가압장치를 설치하여 간편한 방법으로 실린더 내부의 진공상태를 유지할 수 있기 때문에 진공로 속에서의 브레이징 공정이 적용되는 외국제품보다 생산성이 월등함을 알 수 있다. 본 연구에서 개발된 링 프로젝션(ring projection) 용접기법은 초소형 및 소형 실린더 형상의 부품 내부를 진공으로 유지해야 하는 산업현장에서 당장 적용될 수 있는 혁신적인 용접공정이라 판단된다.

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Mg합금판재의 서보가압식 DC점용접에 관한 연구(1) (A Study on Servo DC Resistance Spot Welding of Mg Alloy Sheet(1))

  • 정선녀;장희석;이목영
    • 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.

자동차 새시용 DP60강 인버터 DC 저항 점용접의 용접성 평가 (Evaluation of Weldability on the Resistance Spot Welding of DP60 Steels for Automotive Chassis)

  • 김인주;오익현
    • 한국기계기술학회지
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    • 제13권4호
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    • pp.143-148
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    • 2011
  • This study analyzes the resistance spot weldability of DP60 steels. To analyze the resistance spot weldability of DP60 steels, tensile strength test and macro-section test were conducted for the resistance spot welds. Acceptable welding conditions were determined as a function of the resistance spot welding process parameters such as electrode force, welding time, and welding current. The lower limit of the welding lobe was the minimum shear tension strength for 590MPa-grade steel while the upper limit was determined whether or not expulsion was detected.