Papers by Keyword: Remote Welding

Abstract: In the present work the mechanical behaviour of laser beam welded AZ31B alloy was studied, by changing systematically the spot size of the used fibre laser system between 200 µm and 1000 µm at different power levels between 2 kW and 8 kW. Maximum welding velocities with respect to imperfections were determined. The characterization of the obtained welds - in terms of Vickers hardness, UTS, A_f and weld width, resp. weld area - was correlated with the micro-texture in dependence of the different Focus Spot Diameters and Laser Beam Power levels as well as the resulting cooling rates. Highest UTS of 94% of the base material was achieved with 200 µm Focus Spot Diameter and Laser Beam Power of 4 kW at welding velocity of 100 mm/s. By increasing the Focus Spot Diameter to 600 µm, the tensile strength was reduced to 86 % of the actual strength of the base material.

Abstract: This paper studies the dynamic modeling of weld seam by using the laser vision sensor in virtual environment (VE). By introducing virtual guide (VG), lowering operative difficulty and showing high security can be obtained. Template matching is used to recognize remote weld seam, and the uniform contour of V is defined to represent the features of remote seam. Cubic spline interpolation is employed to construct the continuous model of the seam.

Abstract: Welding seam tracking precision is a key factor influencing welding quality for master-slave robot remote welding system. However, it does not satisfy the welding requirement due to significant noises. To eliminate the influence of noises upon the seam tracking precision and improve the seam tracking precision, a master-slave robot remote welding system was built and Kalman filtering (KF) was applied to the seam tracking process. The experimental results show that the KF eliminated the influence of noises upon the seam tracking precision and improved the seam tracking precision.

Abstract: The welding seam identifying(WSI) is one of remote welding precondition. The welding seam is usually identified by vision sensor. The investigation on WSI based on force sensing is less reported. Because the interaction mechanism of friction is not clear in 6 dimension(6D) force of WSI, the influence of friction on the WSI feed and direction is studied. The experimental results show that the friction will decrease the WSI feed in XSY plane and increase in Z direction, but they is in range permitted by WSI. The friction makes WSI feed direction point to the middle of welding seam track, and do not influence WSI. Above technologies, The WSI of S groove is achieved. The average deviation of WSI is less than ±0.5mm when there is friction in 6D force of WSI. It can meet the precision of WSI in remote welding.

Abstract: Aluminum alloys are extensively used in the automotive industry in response to increasing requirements for weight reduction in car body architecture. Laser welding of Al alloys has many advantages such as low heat input, narrow heat affected zone, minimal thermal distortion and flexibility. Recently, the development of high brightness lasers - thin disk lasers and fiber lasers enable long focal distance welding so that laser remote welding with scanning mirrors can be used in laser welding of Al alloys. In this study, laser remote welding was implemented to a heat shield part of an automobile by utilizing a 4kW disk laser and a 2-axis scanner. By replacing conventional resistance spot welding, the weld flange length could be reduced from 15mm to 8mm and a cycle time for each welding point could also be reduced from 3.5s to 0.6s.

Abstract: This paper presents a generic design and implementation of a telerobotic system application for the remote welding of unstructured and hazardous environment. The objective is to establish a remote welding telerobotic system that is flexibility to carry out welding seam tracing and welding remotely. According to the difference of welding task and environment, this paper presents human machine cooperative control strategies that integrate sensor and model-based computer assistance. The human operator decision and control commands participate into every control level of the teleoperation system. The specific control modes have been presented to integrate into human machine interface (HMI).