• Journal of Welding and Joining
• /
• v.20 no.1
• /
• pp.18-22
• /
• 2002

• Proceedings of the KWS Conference
• /
• 2006.10a
• /
• pp.101-103
• /
• 2006

DSME has developed Sub-assembly Welding Robot System(SWRS) in order to increase the productivity of arc welding and to improve hazard and unclean environments in shipbuilding. DSME's SWRS includes a number of equipments such as four overhanging 6-axis articulated robot manipulators(10kg pay-load), gantry system, vision system detecting the workpiece automatically, and OLP system using the CAD data and a central control system integrating an anti-collision module. The SWRS was installed in CAS(Component Assembly Shop) of DSME's OKPO shipyard in August 2006, and now SWRS is running well in site.

• Journal of the Society of Naval Architects of Korea
• /
• v.44 no.5
• /
• pp.504-508
• /
• 2007

In the case of thin plate blocks, buckling deformation due to longitudinal shrinkage is the most important weld-induced deformation. This paper is concerned with developing the formula to predict the longitudinal shrinkage due to welding, in which mechanical tension effect in welding direction is accounted for. For this purpose, bead on plate welding test has been carried out for the 27 thin plate specimens with varying welding conditions and magnitude of tensile load. Empirical formula of predicting the longitudinal shrinkage has been derived based on the results of welding test, in which effect of mechanical tension is included. The derived formula can be usefully used in predicting the level of tensile load to reduce the longitudinal shrinkage.

• 제어로봇시스템학회:학술대회논문집
• /
• 2005.06a
• /
• pp.626-630
• /
• 2005

This paper presents a novel Intelligent-Welding-Carriage (IWC) for automation of curved block in shipbuilding. The curved block is usually used in both front and back side of the ship. In curved block root gap is big, $1{\sim}7$ [mm] and inclination, $0{\sim}30$ [deg]. Since available conventional carriage type is limited to use below root gap of 3 [mm], only manual welding is employed in curved block. To adopt an IWC in curved block, it requires control of the welding conditions, i.e., voltage, current and travel speed, with respect to root gap and inclination to achieve good welding quality. In this paper, an IWC is developed for automization of welding operation to accommodate gap and inclination. Kinematics model and dynamics using Lagrangian formulation of the manipulator is introduced. IWC utilizes a database to perform accurate welding. The database is programmed based on numerous experimental test results with respect to gap, inclination, material, travel speed, weaving condition, voltage, and current. Finally, experimental result using PID control is addressed for verify the trajectory tracking accuracy of end-effector.

• Special Issue of the Society of Naval Architects of Korea
• /
• 2005.06a
• /
• pp.171-176
• /
• 2005

This paper presents a novel Intelligent-Welding-Carriage (IWC) for automation of curved block in shipbuilding. The curved block is usually used in both front and back side of the ship. In curved block root gap is big, 1-7 (mm) and inclination, 0-30 (deg). Since available conventional carriage type is limited to use below root gap of 3 (mm), only manual welding is employed in curved block. To adopt an IWC in curved block, it requires control of the welding conditions, i.e., voltage. current, weaving speed, dwell time and travel speed, with respect to root gap and inclination to achieve good welding qualify. In this paper, an IWC is developed for automization of welding operation to accommodate gap and inclination. Kinematics model and dynamics using Lagrangian formulation of the manipulator is introduced. IWC utilizes a database to perform accurate welding. The database is programmed based on numerous experimental test results with respect to gap, inclination, material, travel speed, weaving condition, voltage, and current. Finally, experimental result using PID control is addressed for verifying the trajectory tracking accuracy of end-effector.

• Journal of the Korean Society of Clothing and Textiles
• /
• v.37 no.2
• /
• pp.235-245
• /
• 2013

Physiological responses and subjective sensations were evaluated for wearing protective welding clothing in consideration of the work environment for the shipbuilding industry. Experimental clothing was made of oxidant carbon nonwoven fabric (SW2) and oxidant carbon/p-aramid blended fabric (SW4). The values of all items in physiological responses were higher upon wearing oxidant carbon experimental clothing versus wearing oxidant carbon/p-aramid experimental clothing (p<.001). The results of the wearing evaluation in the welding work on-site showed that existing leather protective clothing had a very low satisfaction of permeability, weight sensation and wearing sensation. For the wearing sensation of experimental clothing with SW2, permeability and durability were poor and the pressure and weight sensation satisfaction was very high. In case of SW4, the satisfaction was very high in functional movement, pressure, weight sensation and management aspects; subsequently, the overall wearing satisfaction was very good.

• Journal of Welding and Joining
• /
• v.20 no.3
• /
• pp.67-73
• /
• 2002

In an attempt to evaluate the feasibility of friction stir welding(FSW) for joining carbon steels, microstructures and mechanical properties of friction stir welded carbon steels with different grain structures were investigated. In comparison of O-type stir zone(SZ) appeared in various aluminium alloys, configuration of SZ in friction stir welded carbon steels displayed U-type. Plastically deformed pearlite band structure was identified to surround the SZ, indicating the existence of so-called thermo-mechanically affected zone(TMAZ). However, the TMAZ of carbon steels was much narrower than that of Al alloys. The microstructures of both stir zone and TMAZ revealed bainite matrix in a conventional carbon steel for shipbuilding, while, in the same region, ferrite matrix microstructures were formed in a low carbon fine grained steel. The conventional carbon steel showed superior stirring workability to that of the fine grained carbon steel. The yield and tensile strength of the friction stir welded joints were comparable to those of the base metals, and the elongation in welded joints demonstrated excellent ductility. Absorbed energy in SZ of the fine grained carbon steel was ten times higher than that obtained from conventional submerged arc weld metal of the same steel. Based on these results, the application FSW to carbon steels was found to be feasible.

• Proceedings of the Korea Society for Simulation Conference
• /
• 2003.11a
• /
• pp.185-192
• /
• 2003

Digital Manufacturing-based production could be very effective in shipbuilding in order to save costs and time, to increase safety for workers, and to prevent bottleneck processes in advance. Digital shipbuilding system, a simulation-based production tool, is being developed to achieve such aspects in Korea. To simulate material flow in a subassembly line at a shipyard, the product, process and resources was modeled for the subassembly process which consisted of several sub-processes such as tack welding, piece alignment, tack welding, and robot welding processes. The analysis and modeling were carried out by using the UML(Unified Modeling Language), an object-oriented modeling method as well as IDEF(Integration DEFinition), a functional modeling tool. Initially, the characteristics of the shop resources were analyzed using the shipyard data, and the layout of the subassembly line was designed with the resources. The production process modeling of the subassembly lines was performed using the discrete event simulation method. Using the constructed resource and process model, the productivity and efficiency of the line were investigated. The number of workers and the variations In the resource performance such as that of a new welding robot were examined to simulate the changes in productivity. The bottleneck process floated according to the performance of the new resources. The proposed model was viewed three-dimensionally in a digital environment so that interferences among objects and space allocations for the resources could be easily investigated

• Journal of the Ergonomics Society of Korea
• /
• v.31 no.1
• /
• pp.177-183
• /
• 2012

Objectives: The objectives of this study are to discuss the importance of job stress and to introduce a model of job stress at the shipbuilding industry considering the characteristics of the shipbuilding works. Background: Shipbuilding works consist of grinding, painting, interior works, welding, and assembling and using heavy equipment in narrow space or work at outside or at high and dangerous places. The working environments aggravate the stress to the workers. Methods: Studies of job stress in industries including shipbuilding industries were reviewed and the characteristics of jobs of shipbuilding were analyzed to find causes of job stress. Results: A model was constructed based upon these findings and reviews. Conclusions: Job stress of shipbuilding workers are very high and thus job and working conditions need to be improved to attenuate the level of job stress of shipbuilding workers. Applications: This model can be used to identify the highly stressed workers and sources of stress.

• Proceedings of the KWS Conference
• /
• 2000.10a
• /
• pp.31-33
• /
• 2000

Welding processing is used in the various industrial fields such as shipbuilding, car, airplane and steel structure, etc.. But the welding process has a bad working condition and lack of skillful worker. The welding depended on man power causes low productivity and difficulty in keeping continuous and stable quality control. This paper shows the development results of welding mobile robot with the several functions such as continuous/intermittent welding, initial welding speed control, acceleration control, crater and deceleration speed control in welding end. The robot is developed based on microprocess which is intel 80c196kc.