• Proceedings of the KWS Conference
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• 2002.10a
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• pp.181-186
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• 2002

Laser welding application for car body manufacturing has many advantages in the stiffness and the lightness of vehicle, the productivity of assembly line, and the degree of freedom in design. This presentation will express the innovation of car body manufacturing including parameter optimization, process modeling, and system integration. In this application the investment for systems was cut down dramatically by real time switching over the laser path between two welding stations. Points of technical discussion are as follows: optimization of parameters such as laser power, robot speed and trajectory, compact and useful design of jig & fixture to assure welding quality for 3 sheet-layer zinc-coated steel, system integration between 4kW Nd:YAG laser device and the other systems, on-line real time welding quality monitoring system, perfect safety standards for high power laser, minimization of consumption costs such as arc lamp, protective glass for optic, etc. Laser welding has found a place on Hyundai's production plant in conjunction with the startup of mass production of new sports car, and this production system is the result of a collaboration of its engineers. Outer side sheets are joined to inner side sheets by 122 stitch welds totally. And the length is about 2.4meter.

• Transactions of the Korean Society of Automotive Engineers
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• v.24 no.6
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• pp.709-715
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• 2016

This paper presents a comparison of an experimental study on spot and plug welding of an automotive body panel. Spot welding is a common joining technology used in automotive body panel assembly. In automotive body repair, however, plug welding is widely used due to its technical simplicity and cost benefit. Some researchers have focused on the use of spot welding in the manufacturing process, but there has been very little research done with respect to the engineering analysis of the plug welding process. In this study, two kinds of specimens are considered to compare the difference of failure strength between spot weld and plug weld: normal tension and shear tension. The experimental results show, in both normal tension and shear tension, that spot welding has higher failure strength than plug welding. In addition, plug welding is more vulnerable to shear tension than normal tension. This study can be applied to further studies on practical optimization for maintenance and repair of automotive body panels.

• Korean Management Science Review
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• v.17 no.1
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• pp.135-144
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• 2000

This paper describes a scheduling problem of the panel block assembly shop in a shipbuilding industry. Because the shipbuilding is a labor intensive industry the most important consideration in a panel block assembly shop is the workload balancing. which balances man-hour weight and welding length and so on. It should be determined assembly schedule and workstation considering a daily load balancing and a workstation load balancing simultaneously. To solve the problem we develop a hybrid genetic algorithm. Hybrid genetic algorithm proposed in this paper consists of two phases. The first phase uses the heuristic method to find a initial feasible solution which provides a useful information about optimal solution. The second phase proposes the genetic algorithm to derive the optimal solution with the initial population consisting of feasible solutions based on the initial solution. Finally we carried out computational experiments for this load balancing problem which indicate that developed method is effective for finding good solutions.

• Transactions of the Korean Society of Automotive Engineers
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• v.21 no.3
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• pp.50-57
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• 2013

The high temperature thermal attacks in welding can affect the residual stress of a frame for automotive assembly accompanying frame deformation. Also the residual stress can induce the negative effect on durability performance of the automobile. In order to analyze the frame deformation, the simplified test frame which had the similar shape (form) of the real automotive frame was fabricated. The contactless optical 3D scanner was used for the shape difference measurement of the frame between before and after the welding. The FE-model of the test frame was composed and the deformation and residual stress simulation were performed. The simulated results were compared with the measured results for the reference of the frame design following as the variation of welding sequency. The deformation shape of the frame by simulation was in good agreement with that by the experimental measurement. In addition, the optimized welding sequency with reduced deformation after welding could be achieved through these analyses.

• Journal of the Society of Naval Architects of Korea
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• v.54 no.1
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• pp.57-62
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• 2017

These days, shipbuilding companies are making an effort to adopt the IT technology in order to improve the production efficiency. One such effort is to utilize a planning and scheduling system to predict the production cost in advance. In this system, assessing the welding material quantity is an important factor. Unfortunately, obtaining the welding material quantity in the early design stage is extremely difficult because the detailed production information, which is essential in deriving the cost associated with welding, is normally available at a later stage. This paper aims at developing a computerized program that produces an index to estimate the welding material quantity in the early design stage. By using only three-dimensional geometric information, the program analyzes the production process and estimates the welding material quantity at any design or production stage when no production information is available. The results can be used for the planning and scheduling system.

• Journal of Welding and Joining
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• v.31 no.4
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• pp.1-6
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• 2013

Nowadays, the weight lightening of automotive is required as conserving the environment has become a major worldwide issue. To solve this issue, various researches for the use of light materials(Alalloy, Mgalloy)and ultra high strength steel as substitutes of the current structural material have been carried out. Application of laser stitch welding to the assembly of automotive produces improvement in strength, lightening of body, higher fuel efficiency, lower production cost as well as reduction in assemble line due to its fast welding speed, superior accessible and weld quality. This process overcomes the shortcomings of the current resistance spot welding such as high electricity consumption, electrode replacement, and economical, technical limitation in design and production method of automotives.

• Proceedings of the KWS Conference
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• 2006.05a
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• pp.92-93
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• 2006

In recent time there are vigorous requirement for the use of thick steel plate in various industrial fields including shipbuilding industry. Application of TMCP steel plates, especially, is increase progressively. As a welding process for thick steel plate assembly high heat input welding method is used. However, HAZ softening of TMCP steel plates has a possibility to reduce the strength of welded joint. In this study, therefore, tensile strength of TMCP welds had softened HAZ was examined using numerical calculation and experiment.

• Proceedings of the KSME Conference
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• 2003.11a
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• pp.1757-1762
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• 2003

For coping with various ship types easily, welding automation using CAD/CAM is demanded and and developed. In this paper we propose a dedicated CAM system which generates MACRO files to control robot manipulators. The paper contains CAD interface, virtual simulation, macro generation and job schedulling. At first, it defines and extracts weldline from CAD data, and generates proper MACRO programs. And it obtains optimum job schedules. This system removes the manual work, and consequently reduces the overall lead time. And it reduces costs and time for developing robot welding programs. This can be expanded to virtual factory simulation technology. Moreover, it is possible to apply this system for automation of Cutting and Painting

• Proceedings of the KWS Conference
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• 2007.11a
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• pp.20-22
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• 2007

Welding-induced buckling distortion at the free edge of thin-plated panels has been studied. Welding distortion at free edges causes the additional man hours to straighten for the easy adjusting works of the following assembly stage. Therefore, it is necessary to develop a free-edge distortion control method. It is the purpose in the study to evaluate the effectiveness of buckling distortion prevention of the current design practice and design modification.

• Journal of Industrial Technology
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• v.27 no.A
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• pp.69-76
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• 2007

The body of an excavator, one sort of the construction equipment, consists of mainframe part, track frame part, boom part and arm part. The all parts are manufactured in the body welding operation. The scheduling in the body welding operation of a construction equipment manufacturing is to take all the various constraints into consideration. The offset time, due date, daily capacity of operations, daily jig's capacity, precedence relation, outsourcing, alternative resource and all of the shop floor environment should be considered. An APS(Advanced Planning & Scheduling) system is a proper and efficient system in such circumstance. In this paper, we present an APS system, the optimal scheduling system for the construction equipment manufacturing specifically for the body welding operation, using ILOG Solver/Scheduler. ILOG Solver/Scheduler is a general purposed commercial software which supports to find a feasible or optimal solution using object oriented technique and constraints satisfaction programming, given constraints and objectives.