• Korean Journal of Computational Design and Engineering
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• v.18 no.5
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• pp.321-328
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• 2013

A method of designing a manufacturing shape of ship plate parts considering welding deformation is introduced. In this paper, the design shape of a bracket is deformed not by a thermoelastic method but by a pure geometric method. Deformation quantities are estimated based on data captured in the field and then a manufacturing design shape is obtained by deforming an original design shape by a geometric deformation method. The proposed method has been implemented and tested in the shipyard.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.159-159
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• 2000

최근 조선분야의 경우 생산원가의 절감, 품질의 고급화, 단순작업에 대한 근로기피 등의 이유로 로봇시스템 적용에 대한 필요성이 크게 대두되고 있다. 그러나 기존의 로봇 시스템의 교시방식이 교시-재생(Teaching-Playback)방식이어서 작업부재의 형상 및 치수가 매번 변경되는 중공업 분야에서는 적용이 불가능하였다. 본 연구에서는 조선용 아크용접 로봇을 위한 오프라인 프로그램밍(OLP: Off-Line Programming) 시스템을 개발하였다. 오프라인 프로그램밍 시스템의 경우 작업중인 로봇과는 상관없이 다음 부재에 대한 형상 데이터만을 이용하여 컴퓨터상에서 다음 작업프로그램을 미리 생성할 수 있으므로 기존의 온라인 교시-재생 방식의 교시시간의 과다라는 문제를 극복할 수 있다. 본 연구에서는 강교 판넬 및 조선 소조립용으로 개발 중인 아크용접용 로봇 시스템을 위한 오프라인 프로그래밍 시스템을 개발하였다. CAD 데이터나 OLP의 모델링 기능으로 작업부재를 형상한 후 미리 데이터베이스화 되어 있는 자료를 검색하여 부위별 작업매크로 확보를 위하여 실제 로봇 시스템을 이용한 작업테스트를 수행하였다. 개발된 오프라인 프로그래밍 시스템은 기능보완 후 당사 아크용접용 로봇시스템에 적용될 계획이다.

• Journal of the Society of Naval Architects of Korea
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• v.44 no.6
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• pp.590-597
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• 2007

The portion of thin plate is expected to increases as to the development of design and fabrication technology. The weld-induced deformation is more serious in thin plates than in thick plates because heat affect zone of thin plates is wider than that of thick plates, and in addition internal and external constraints much more influence upon weld-induced deformation of thin plates. This paper is aimed at applying the mechanical tensioning method to fillet weld of thin plates to reduce the weld-induced deformation. For this purpose, fillet welding tests have been carried out for several thin plate specimens with varying plate thickness and magnitude of tensile load. From the present study, it has been found that the tensioning method is effective on reduction of weld-induced deformation.

• Journal of Welding and Joining
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• v.1 no.1
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• pp.21-29
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• 1983

용접구조물에는 필연적으로 용접에 의해서 생기는 부정량이 존재한다. 용접에 의해서 건조되는 선체구조에 있어서도 misalignment를 비롯하여 과대한 gap, 팬널(panel)의 초기변형, 용접에 의한 수축과 같은 부정량이 존재하여 선속 불록의 정도와 선체 강도에 영향을 주게 된다. 그래서 일본에서는 건조되는 동선의 품질을 고도로 유지하면서 공수를 될 수 있는 한 줄이기 위하여 이론과 실속이 뒷받침된 신속도가 높은 품질표준을 설정하는 것이 필요하다고 판단하여 1964년에 '일본동선공작법표준, japan shipbuilding quality standard(JSQS)'를 제정하였다. 그 내용에는 소재, 현도, 내용 가공부재, 조립 블록, 선형확보, 다듬질, 변형량등 주로 공정순에 따라 각각 구 분을 정한 항목마다 표준범위와 허용 한계가 표시되어 있다. 지금부터 용접에 의한 부정량의 대표예로써, 용접에 의한 변형과 잔유응력, 이음에서의 gap과 misalignment에 대하여 말하고 아울러 부정량과 JSQS와의 관계에 대해서도 간단히 말하겠다.

• Journal of Welding and Joining
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• v.27 no.5
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• pp.74-80
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• 2009

The membrane of the LNG carriers consists of thin strips of INVAR(Fe-36%Ni) steel plates, and the junction between INVAR strips is fabricated by welding. Thousands of the raised edge joints, regularly spaced, are located around all the side of the tank corner near the transverse bulkhead, and TIG welding is manually made on the top of the raised edges. Since the thickness of all the laminated edge plies is extremely thin and the weld position is under a bad accessibility, highly skilled workers are required to perform welding relatively for a long welding time. An alternative scheme for the corner membrane fabrication is proposed in the study to improve the installation workability and thus productivity. The scheme replaces the welded edges with the preformed corrugation ones. A panel strip with regularly-spaced corrugations is installed at the corner instead of the individual flat strip of which edge is vertically raised to be welded with the adjacent strip. In the study, a series of the evaluation on the corrugated edge members was performed to assess the applicability to the real LNG carrier fabrication. Opening displacement at the raised edge was experimentally examined. Elastic stiffness regressed from the displacement was nearly same in both edge types. Edge displacement and local stresses were calculated under hydrostatic pressure and temperature change due to liquefied cargo. Fatigue test was performed on both corrugated and welded edge specimens consisting of two or five plies of invar strips. Fatigue strength of the corrugated specimens was not less than that of the welded specimens.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.40 no.10
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• pp.901-906
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• 2016

The purpose of this study is to improve productivity by implementing one-pass full penetration welding using laser-arc hybrid welding for AH36. On increasing the thickness of the plate, a higher power of laser and arc was required to obtain full penetration. However, increasing the power of heat source caused undercut defects at both ends of the bead. This undercut was prevented by controlling the parameters of welding voltage and pulse correction. Hardness measurement and tensile test were conducted to apprehend the mechanical properties of weld. Also, by carrying out the microstructure observation for laser and arc regions, microstructural properties were understood.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.517-517
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• 2000

Welding automation is one of the most important manufacturing issues in shipbuilding in order to lower the cost, increase the quality, and avoid the labor problems. Generally the on-line teaching is utilized on the robot that is used in the welding automation system, but it requires much effort and long time to program. Especially, if the system is composed of more than two cooperating robots, it demands much more skill to program the robots' motion. Thus, a convenient programming tool is required for efficient utilization of welding automation system. In this study, a convenient programming tool is developed for welding automation in which gantry-robot system is used. The system is composed of a gantry transporter and two robots mounted on the gantry to cover the wide work range in the ship building application. As a programming tool, an off-line programming software based on PC is developed. By using this software, field operator does not need to concern about coding of task programs for three control units, one is for gantry and two are for robots. The task programs are automatically generated by assembling the program modules in database according to geometrical information of workpiece and welding condition, which become the only concern of field operator, The feasibility of the generated programs can be verified via a motion simulator previously to on-line running.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.8
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• pp.4717-4722
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• 2014

In shipyards, a large number of dog-pieces are used to align welding joints and prevent welding deformation in the block assembly stage. The huge working man-hours consumed in the working process of dog-pieces impedes the productivity growth of shipyards. In this study, an analysis method based on the experimental results was proposed to simulate the welding deformation of butt joints with a dog-piece setting. The simulation of welding deformation of a hull block joint was performed using the proposed analysis method. Finally, the proposed analysis method can be used to establish guidelines for the proper use of dog- pieces in the block assembly stage.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.26 no.4
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• pp.556-561
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• 2022

In this paper, we present a block media communication (BMC) system which employs powerline communication to the equipments used in the welding process for ship-assembly and uses metal block as a communication medium. Inductive couplers are installed on digital feeder and pin jig. Information signal is added to the current generated by the welding gun, and applied to the block. When the welding operation starts, information generated in the field is transmitted to the monitoring server in real-time. The field test on the BMC system confirms that the transmitted data are correctly received at the server. Since the proposed system can be built without any changes to the existing welding process, it is helpful to increase competitiveness of the shipbuilding industry through smart factory of shipyards. It is also possible to quickly respond to emergency situations that may occur to workers in an electromagnetic wave shielding environment or a closed space, the effect of preventing industrial accidents will be great.

• Proceedings of the KWS Conference
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• 2010.05a
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• pp.51-51
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• 2010

Recently just as in the automobile industry, shipbuilders also try to reduce material consumption and weight in order to keep operating costs as low as possible and improve the speed of production. Naturally industry is ever searching for welding techniques offering higher power, higher productivity and a better quality. Therefore it is important to have a details research based on the various welding process applied to steel and other materials, and to have the ability both to counsel interested companies and to evaluate the feasibility of implementation of this process. Submerged-arc welding (SAW) process is usually used about 20% of shipbuilding. Similar to gas metal arc welding(GMAW), SAW involves formation of an arc between a continuously-fed bare wire electrode and the work-piece. The process uses a flux to generate protective gases and slag, and to add alloying elements to the weld pool and a shielding gas is not required. Prior to welding, a thin layer of flux powder is placed on the work-piece surface. The arc moves along the joint line and as it does so, excess flux is recycled via a hopper. Remaining fused slag layers can be easily removed after welding. As the arc is completely covered by the flux layer, heat loss is extremely low. This produces a thermal efficiency as high as 60% (compared with 25% for manual metal arc). SAW process offers many advantages compared to conventional CO2 welding process. The main advantages of SAW are higher welding speed, facility of workers, less deformation and better than bead shape & strength of welded joint because there is no visible arc light, welding is spatter-free, fully-mechanized or automatic process, high travel speed, and depth of penetration and chemical composition of the deposited weld metal. However it is difficult to application of thin plate according to high heat input. So this paper has been focused on application of the field according to SAW process for thin plate in ship-structures. For this purpose, It has been decided to optimized welding condition by experiments, relationship between welding parameters and bead shapes, mechanical test such as tensile and bending. Also finite element(FE) based numerical comparison of thermal history and welding residual stress in A-grade 3.2 thickness steel of SAW been made in this study. From the result of this study, It makes substantial saving of time and manufacturing cost and raises the quality of product.