Papers by Author: Jeong Suh

Abstract: On this paper, a study of robot based remote laser welding technology for manufacturing light car body was conducted. Laser welding and industrial robotic systems were used with robot-based laser welding systems. The laser system used in this study was 1.6kW fiber laser, while the robot system was Industrial robot (payload : 130kg). The robot-based laser welding system was equipped with a laser scanner system for remote laser welding. Laser patterning on the fly needs to control some parameters to accomplish the desired shape and good quality of the welded pattern. The scan path and the mark speed as two control parameters of the laser scanner are numerically computed from pattern shape and robot motion. However, time-delay in operation of the laser scanner and the robot makes unexpected geometric error between the desired pattern and the welded pattern. The pattern sequence and the robot path is optimized to reduce total processing time. The proposed method is tested with various patterns and robot paths, and the welded patterns are validated by measuring their geometries and positions. Finally, the experimental results show that our method is suitable for laser patterning on the fly. The welding joints of steel plate and steel plate coated with zinc were butt and lapped joints. The quality testing of the laser welding was conducted by observing the shape of the beads on the plate and the cross-section of the welded parts, analyzing the results of mechanical tensile test. The remote laser welding system with laser scanner system is used to increase the processing speed and to improve the efficiency of processes. This paper proposes the robot-based remote laser welding system as a means of resolving the limited welding speed and accuracy of conventional laser welding systems.

Abstract: This paper describes the development of a reconfigurable 3D profile measurement system for welding robot. The system consists of a PC based vision camera and a stripe-type laser diode. The total system is assembled into a compact module which can be attached to the endeffector of welding robots. Especially, the developed system is designed to operate at different working distances. For this purpose, the reconfigurable mechanism which adjusts the focal length and the relative position between the camera and the laser diode is devised. These two configurations are automatically changing, according to the current working distance. Most parts of image processing such as camera calibration, correction of distortion, and line extraction are implemented and running on the PC. After measuring the welding profile, the 3D shape of the parent metal is obtained and some useful features for robot manipulation are calculated.

Abstract: Pulsed UV laser beams, which are widely used in the processing of polymers, offer many advantages in the field of polymer production, primarily because their photon energy is higher than the binding energy of the polymer. In particular, the fabrication of polymers with an excimer laser process is faster and more convenient than with other processes. Nevertheless, some problems occur in the precision microprocessing of polymers, including the formation and deposition of surface debris, which is produced from the breakdown of either polymer chains or radical bonds. In the present work, a process for eliminating carbonized surface debris contamination generated by the laser ablation of a polymer was developed. The proposed approach for removing surface debris utilizes an erasable ink pasted on the polymer. The surface debris ejected from the polymer is then combined with the ink layer on the polymer. Finally, both the surface debris and the ink layer can be removed using adhesive tape.