• 제목/요약/키워드: weld seam

검색결과 144건 처리시간 0.021초

혼합가스 GMA 용접에서 아크신호를 이용한 용접선추적에 관한 연구 (A study on seam tracking with an arc signal in GMA welding process with mixed gas)

  • 허장욱;김재웅;이승영
    • Journal of Welding and Joining
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    • 제8권1호
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    • pp.23-30
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    • 1990
  • The robotic welding has been adapted positively in many welding shops forthe purpose of improving the welding efficiency and liberating operators from the severe working atmosphere. But for a large-size structure with thick plates like ship-building and every kind of plants manufacturing, the application of the arc welding robots is not established yet. The reason is assumed that the conventional arc welding robots are not adaptive for multi-pass welding of thick plates whose grooves are not so accurate. As one solution to this problem, a guidance system which uses the welding arc itself as a sensor is largely used. In this study the velocity controller which changes the tip to workpiece distance for regulating the weld proposed. The proportional and integral gain of velocity controller were determined by using the computer simulation of the control system, and the simulation results compared with the experimental ones. It was revealed that the developed control system using the arc sensor principle has a good capability of tracking the weld joint, although some more studies will be needed to refine the model of arc current.

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모서리 부위 연속 용접을 위한 아크 용접 로봇 시스템의 궤적 개발 (Trajectory Development of Robotic Arc Welding System for Continuous Welding of Corner Area)

  • 장교근;유범상
    • Journal of Welding and Joining
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    • 제14권6호
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    • pp.68-80
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    • 1996
  • When a workpiece is to be arc welded around the outside corner, continuous welding without welding seam in the neighborhood of comer still remains a very difficult technique. Skilled welders weld comers by delicate“hand-eye coordination”while turning the workpiece manually, However, there is not a very clear solution to this problem in robotized arc welding process. In order to solve this problem, the coordination of a robot and a positioner with one or two axes is necessary. This paper presents a method of continuous welding around the corner of workpiece using the coordinated motion of a robot and a positioner. The positioner is either revolute jointed or prismatic jointed. In this paper, a clothoid curve is chosen for welding trajectory. The clothoid curve is excellent in connecting straight and curved weld-lines with good continuity and accommodates various welding conditions. By using this welding trajectory, the deceleration, which leads to widening of the melt and the heat affected zone, at comer area is reduced with strategic rotation of robot torch in coordination with a positioner providing smooth transition of welding torch orientation. Two types of special clothoid curves are developed for different weld slope conditions. These clothoid curves are applied to the case of linear and rotary Positioners at arc welding robot work-cell.

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Flux Cored Arc용접용 아크센서의 개발 및 이를 이용한 용접선 추적에 관한 연구 (A Study on the Development of Arc Sensor for Flux Cored Arc Welding Process and its Application for Seam Tracking)

  • 김수영;이승영;나석주
    • Journal of Welding and Joining
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    • 제10권4호
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    • pp.190-198
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    • 1992
  • Among the variety of welding processes available, the flux cored arc welding is one of the most frequently used process, because of its wide range of application and high productivity. The weld joint tracking is indispensable to improve the flexibility of the arc welding robot application for the flux cored arc welding (FCAW) process. In this study, an arc sensor which utilizes the electrical signal obtained from the welding arc itself was developed for weld joint tracking in FCAW. Because a model of the welding arc in flux cored arc welding was required to develop the arc sensor, a mathematical model was proposed by analysing the welding arc behaviour, and also an experimental model by using the factorial experiment and least square method. For overcoming the fluctuation in the welding current signal during tracking the weld joint, it was fitted to a curve which is inversely proportional to a trace of tip-to-workpiece distance by using the quadratic curve-fitting method.

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스캐너를 이용한 AZ31 극박판재와 AZ91D 다이캐스팅 프레임의 고속레이저용접 (Fast laser welding with scanner on the joint between AZ31 thin sheet and die-casted AZ91D frame for smart phone application)

  • 이목영;서민홍
    • 한국레이저가공학회지
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    • 제18권1호
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    • pp.1-6
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    • 2015
  • High welding speed and narrow weld seam are favorable for welding of magnesium alloy. Magnesium alloy is recommended for the smart frame because it has several advantages such as low density, high thermal conductivity, EMI shielding capability and good cast ability. This study is for the assembly welding of the magnesium smart frame with high productivity, good performance and low cost. The window for battery on AZ91D frame produced by die-casting was prepared by CNC machining. Corresponding AZ31 blank of 0.2mm thickness was prepared by die-blanking cut. All system set was fixed at the stationary bed but the laser beam was manipulated by scanner up-to 1,000mm/s speed. The weld joint between AZ31 sheet and AZ91D frame was welded by fiber laser on 850~1,000W output power. The joint showed penetration enough but some humping bead. The distortion by the weld heat was almost free because of the quick dissipation of the heat by small beam size and fast welding. Consequently, the thinner magnesium foil was assembled successfully to the magnesium frame of mobile phone.

고속 다전극 자동 용접 시스템 (Automatic Multi-torch Welding System with High Speed)

  • 문형순;고성훈;김용백
    • Journal of Welding and Joining
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    • 제25권2호
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    • pp.49-54
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    • 2007
  • Since the wall thickness can be up to 6" or greater, welds must be made in many layers, each layer containing several passes. However, the welding time for the conventional welding processes such as SAW(Submerged Arc Welding) and FCAW(Flux Cored Arc Welding) can be required many hours. The aim of this paper is to develop a high speed welding system with multi-torch and laser vision sensor for increasing the production speed on the line and to remove the need for the operator so that the system can run automatically for the complete multi-torch multi-layer weld. It was shown that the developed laser vision sensor and analysis of arc blow for multi-torch were effective for multi-pass seam tracking and stable arc. A new automated multi-torch welding systems for thick wall applications has been proved in several production lines.

수중용 선체외판 길함 검사용 장치 개발 (An Underwater Inspection System to Detect Hull Defects of a Ship)

  • 김영진;조영준;이강원;손웅희
    • 한국해양공학회:학술대회논문집
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    • 한국해양공학회 2006년 창립20주년기념 정기학술대회 및 국제워크샵
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    • pp.281-284
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    • 2006
  • After building a ship in a shipyard, there are so many repeated inspection of welding seam defects and painting status before delivering to the ship's owner. An inspection on the bottom part of a ship in commercial service should be done in every two years for the purpose of safety and for the prevention of ship speed deterioration. conventional welding seam inspection systems are rely on the visual inspection by human or the ultrasonic inspection for the selective part of a ship. This paper suggests a remote controlled inspection system for the examination of large ships or steel structures. The proposed system moves in contact with the ship under inspection and have a CCD camera to provide visual-guidance information to a remotely located human worker. Additionally this system utilizes a weld line tracking algorithm for an optimal position control. We verified the effectiveness of the inspection system by experimental data.

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시각센서를 이용한 벨로우즈 외부 모서리 레이저 용접 시스템의 개발에 관한 연구 (A Study on Development of Laser Welding System for Bellows Outside Ege Using Vision Sensor)

  • 이승기;유중돈;나석주
    • Journal of Welding and Joining
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    • 제17권3호
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    • pp.71-78
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    • 1999
  • The welded metal bellows is commonly manufactured by welding pairs of washer-shaped discs of thin sheet metal stamped from strip stock in thickness from 0.025 to 0.254 mm. The discs, or diaphragms, are formed with mating circumferential corrugations. In this study, the diaphragms were welded by using a CW Nd: YAG laser to form metal bellows. The bellows was fixed on a jig and compressed axially, while Cu-rings were installed between belows edges for intimate contact of edges. The difference between the inner diameter of bellows and jig shaft causes an eccentricity, while the tolerance between motor shaft and jig shaft causes a wobble type motion. A vision sensor which is based on the optical triangulation was used for seam tracking. An image processing algorithm which can distinguish the image by bellows edge from that by Cu-ring was developed. The geometric relationship which describes the eccentricity and wobble type motion was modeled. The seam tracking using the image processing algorithm and the geometric modeling was performed successfully.

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AUTOMATIC MULTITORCH WELDING SYSTEM WITH HIGH SPEED

  • Moon, H.S;Kim, J.S.;Jung, M.Y.;Kweon, H.J.;Kim, H.S.;Youn, J.G.
    • 대한용접접합학회:학술대회논문집
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    • 대한용접접합학회 2002년도 Proceedings of the International Welding/Joining Conference-Korea
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    • pp.320-323
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    • 2002
  • This paper presents a new generation of system for pressure vessel and shipbuilding. Typical pressure vessel and ship building weld joint preparations are either traditional V, butt, fillet grooves or have narrow or semi narrow gap profiles. The fillet and U groove are prevalently used in heavy industries and shipbuilding to melt and join the parts. Since the wall thickness can be up to 6" or greater, welds must be made in many layers, each layer containing several passes. However, the welding time for the conventional processes such as SAW(Submerged Arc Welding) and FCAW(Flux Cored Arc Welding) can be many hours. Although SAW and FCAW are normally a mechanized process, pressure vessel and ship structures welding up to now have usually been controlled by a full time operator. The operator has typically been responsible for positioning each individual weld run, for setting weld process parameters, for maintaining flux and wire levels, for removing slag and so on. The aim of the system is to develop a high speed welding system with multitorch for increasing the production speed on the line and to remove the need for the operator so that the system can run automatically for the complete multi-torch multi-layer weld. To achieve this, a laser vision sensor, a rotating torch and an image processing algorithm have been made. Also, the multitorch welding system can be applicable for the fine grained steel because of the high welding speed and lower heat input compare to a conventional welding process.

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용접선 추적용 전자기센서의 제어시스템 개발 (Development of a Dual Electromagnetic Sensor-Based Weld Line Seam Tracking System)

  • 조방현;민기업;아미트;김동호;김수호;권순창
    • 대한용접접합학회:학술대회논문집
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    • 대한용접접합학회 2005년도 추계학술발표대회 개요집
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    • pp.144-146
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    • 2005
  • Dual electromagnetic sensor is used for sensing the weld line. The sensor consists of excitation and two sensing coil wound over the ferro-magnetic core. By using the dual sensor, the effect of noise is minimized. It is based on the generation of eddy currents in the welding plate by passing current through the excitation coil. The sensor can be used to track the butt joints having no gap between them, where a vision based sensor fails to track. Sensor sensitivity depends on the number of coil turns, frequency of excitation, distance of a sensor from the work piece, diameter of core, etc. The whole system consists of a sensor, a signal processing board, a motion controller and a personnel computer (PC). The raw sensor signal is processed using the signal processing board. It consists of amplification, rectification, filtering, averaging, offset adjustment, etc. Based on sensor data, the motion controller adjusts the position of a welding torch.

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펄스 레이저를 이용한 벨로우즈 용접특성에 관한연구 (Welding characteristics of Metal bellows using a pulsed Nd:YAG laser)

  • 김정오;이제훈;서정;이승우
    • 한국레이저가공학회지
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    • 제15권1호
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    • pp.10-14
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    • 2012
  • Pulse laser welding was performed on C22 metal bellows. The results can be summarized as follows: Laser welded metal bellows had less thermal distortion, narrow HAZ, high aspect ratio in comparison with other welding processes like TIG, Plasma welding. Laser welded bellows has higher tensile strengths than that C22 base metal. The value of hardness in laser weld metal was measured 100-120 Hv, it was decreased compared to the base metal. It is reasoned that due to the annealed by heat input during the laser welding.

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