• Journal of Welding and Joining
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• 제27권2호
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• pp.57-62
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• 2009

This research was carried out to improve the productivity in the subassembly process of shipbuilding through optimal work planning for the shortest work time. The work time consist of welding time, moving time of gantry, teaching time of robot and robot motion time. The shortest work time is accomplished by even distribution of work and the shortest welding sequence. Even distribution of work was done by appling the simple algorithm. The shortest work sequence was determined by using GA. The optimal work planning decreased the total work time of the subassembly process by 4.1%. The result showed the effectiveness of the suggested simple algorithm for even distribution of work and GA for the shortest welding sequence.

• Journal of Welding and Joining
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• 제25권4호
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• pp.79-85
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• 2007

The industrial disaster caused by a work-related disease like a Musculoskeletal Disorders(MSDs) becomes a big social problem and increases rapidly. This leads to the degradation of the labor desire and the productivity. Welding work belongs to the work with a high intensity. This paper aims to analyze the welding work in the various positions from a view-point of the burden of the human musculoskeletal system and to propose the desired position with lower burden. For this purpose the real welding work was observed in the shipyard and analyzed using the RULA method, a powerful ergonomics tool. The 3-dimensional simulation model fur this work was also developed. In this model, ergonomics human model and welding work environment were built. This model was verified through the comparison to the real work. This paper showed that the improvement of welding position by changing the location of a stool and using some auxiliary tool can reduce the work intensity remarkably and lead to the decrease of MSDs.

• 한국생산제조학회지
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• 제6권2호
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• pp.92-101
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• 1997

The purpose of this welding process of the exclusive welding-machine using welding torch-rotation type is to develop a mechanism which can solve the problem of twisting of welding wires and cables. The technique was developed by revising the torch position and smooth controlling of both the normal and reverse rotation. Some of the advantages of using the torch-rotation type apply to the work-rotation technique are the practical uses of increased work space and link work with the factory automation system. Do apply the welding process, I designed and made a special unit so called torch part in order to solve the problems of kinematical. And I made a control panel which can manipulate the progress of the entire process at the work shop. Even if it will be applied to another kind of axle casing's welding work, this process can be utilized if other sizes of the fixed pin and work part is produced and changed. The development of this exclusive welding-machine could reduce the manpower of skilled welding labor and increase productivity and better quality product in comparison to the handmade product.

• 한국환경보건학회지
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• 제33권6호
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• pp.506-512
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• 2007

This study was conducted to describe the exposure levels of welding fumes by the type of manufacturers, work process, welding type and the size of manufacturers, and to find out the trend of chronological changes of airborne welding fume levels. The subjects of this study were 509 manufacturers, consisting of 11 types of manufacturers, 3 work processes, 7 welding types, in Busan from January, 1997 to December, 2005. Airborne concentration of welding fume was determined by manual of National Institute for Occupational Safety and Health (NIOSH), and the data were analyzed by using SPSS 10.0 for Windows program. The mean concentration of airborne welding fume in all manufacturers was $1.29\;mg/m^3$ (Range: $0.01{\sim}3.00\;mg/m^3)$. The level of welding fume was the highest, as $1.96\;mg/m^3$, for manufactures of motor vehicles, trailers and semi-trailers, which was lower than $5.0\;mg/m^3$ of 8 hr-TWA in Korean permissible exposure limit for welding fume. There was a significant difference in the mean levels of welding fumes by work process, showing the highest in welding workshop ($1.39\;mg/m^3$), followed by pipeline welding workshop ($1.26\;mg/m^3$) and engineering workshop ($1.20\;mg/m^3$). Among welding types, the mean level of welding fume was the highest in the type of $CO_2$ & arc welding, as $1.46\;mg/m^3$, followed by $CO_2$ welding ($1.40\;mg/m^3$), shielded metal arc welding ($1.31\;mg/m^3$), spot welding ($1.27\;mg/m^3$), and so on. The highest mean level of welding fume was $1.58\;mg/m^3$ in work process of pipe line welding workshop for the manufacturers of basic iron and steel, and $2.27\;mg/m^3$ in the type of arc welding for the manufactures building ship and boats. By the size of manufacturers, the mean concentration of welding fume for manufactures in small scale with less than 50 workers was the highest as $1.45\;mg/m^3$ (Range: $0.07{\sim}3.00\;mg/m^3)$. The mean level of welding fume was the highest as $1.39\;mg/m^3$ both in 1997 and in 2005, showing a trend of fluctuating periodically within a range of $1.10{\sim}1.39\;mg/m^3$. The above results suggested that more effective control program for work environment producing welding fumes should be developed and applied since there were significant variations in welding fume levels by the type of manufacturers, work processes, welding types, the size of manufactures, and by year.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1996년도 추계학술대회 논문집
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• pp.810-814
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• 1996

The purpose of this exclusive welding-machine process using the welding Torch-rotation form is to develop a mechanism which can solve the problem of twisted welding wires and cables. The technique was developed by revising the torch position and smooth controlling of both the formal and reverse rotation. Some of the advantages of using the Torch-rotation form over the Work-rotation technique are the practical uses of increased work space and link work with the automation system of the plant. Using this welding machine process, It is possible to design a specific tool in order to solve the implemental problem. And I produced a control plate which can manipulate the progress of the entire process at the work place. Even if another kind of axle casing's welding work is used this process can be utilized if the fixed tip and work is produced and changed. The development if this exclusive welding-machine could reduce the manpower of skilled welding labor and after considerable analysis, this machine was found to increase productivity and better quality product in comparison to the handmade product.

• Journal of Welding and Joining
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• 제24권5호
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• pp.62-66
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• 2006

Panel line is an important process occupying the largest work amount in shipbuilding. In this research product simulation has been carried out to establish the optimal production scheduling. For this purpose a web-based panel line simulator was developed using an object modeling technology and C# language. The balance of work-load and increase in the productivity by the improvement of production facilities and process are the key factors for a good scheduling. In this study SPRT(Shortest Remaining Process Time) rule was applied for the work-load balancing and a good result achieved. To increase the productivity in the stiffener welding stage which is a bottleneck; process, more welding heads and higher welding speed were tested using the developed simulator. The simulation results showed that either more welding head or higher welding speed decreased the total work time. Use of both, however, deteriorated the productivity because of the bottleneck in the following stage. This result points out that the improvement of production facilities and/or process should be evaluated with their influences on the leading and following processing stage.

• 패션비즈니스
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• 제15권2호
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• pp.145-159
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• 2011

The study aimed to analyze the status quo of manufacturing work environment and the work clothes' clothing comfort and wearer mobility of welding and grinding work processes in the machine and shipbuilding industries in South Korea. A questionnaire survey was conducted for the study, which consisted of questions about work clothes' clothing comfort and wearer mobility according to body parts. The findings derived from the research were: the high impact levels of work environment factors on welding and grinding work processes were noise, metal fragment, superheat, toxic gas, UV ray factors. Subject workers' assessment of work clothes' clothing pressures were in the levels between 3 (i.e. moderate) and 4 (i.e. comfortable) in a range of 5-point scale. The impact levels of wearer mobility factor were high on the work processes of welding and grinding in machine and grinding in shipbuilding. While welding process in shipbuilding showed a 'moderate' wearer mobility level and this was because its work postures were uncomfortable yet the rate of the motion change was low. The consideration to develop the work clothes specialized for certain work processes should include the materials' protecting performance from the hazardous work environment factors; and work clothes' designs that provides workers with maximized clothing comfort and wearer mobility for bending or tilting postures of upper, lower and lateral body parts defined in the study.

• Transactions on Control, Automation and Systems Engineering
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• 제3권2호
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• pp.124-132
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• 2001

Autonomous of welding process in shipyard is ultimately necessary., since welding site is spatially enclosed by floors and girders, and therefore welding operators are exposed to hostile working conditions. To solve this problem, a welding robot that can navigate autonomously within the enclosure needs to be developed. To achieve the welding ra나, the robotic welding systems needs a sensor system for the recognition of the working environments and the weld seam tracking, and a specially designed environment recognition strategy. In this paper, a three-dimensional laser vision system is developed based on the optical triangulation technology in order to provide robots with work environmental map. At the same time a strategy for environment recognition for welding mobile robot is proposed in order to recognize the work environment efficiently. The design of the sensor system, the algorithm for sensing the structured environment, and the recognition strategy and tactics for sensing the work environment are described and dis-cussed in detail.

• Journal of Welding and Joining
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• 제28권2호
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• pp.27-31
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• 2010

Generally, angle pieces at the corners of cargo tank of membrane type LNG carrier ship are manually welded, due to their various shapes and positions. In this study, a GTA welding robot system was developed in order to improve productivity, which consists of a 7-axis manipulator, a system controller, a GTA welding power source, and peripheral devices. The welding system is characterized by capabilities of welding corrugated work pieces as well as 90/135 degree linear work pieces, and controlling the entire weld cycle automatically. The developed system was field tested on actual work pieces and its performance was proven to be successful.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2003년도 춘계학술대회 논문집
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• pp.185-190
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• 2003

At the present, a stud bolt welding was achieved by the manual method. The manual method caused many problems of work evasion. In order to work out these problems, an automatic welding system is designed for a stud bolt welding system. The system is composed of articulated type welding robot, stud gun, stud feeder, stud controller and various jig.