Local Shielding Gas Supply in Remote Laser Beam Welding

The use of shielding gases in laser beam welding is of particular interest for materials interacting with ambient oxygen, e.g., copper, titanium or high-alloy steels. These materials are often processed by remote laser beam welding where short welds (e.g., up to 40 mm seam length) are commonly used. Such setups prevent gas nozzles from being carried along on the optics due to the scanner application and a small area needs to be served locally with inert gas. The article provides systematic investigations into the interaction of laser beam processes and parameters of inert gas supply based on a modular flat jet nozzle. Based on the characterization of the developed nozzle by means of high-speed Schlieren imaging and constant temperature anemometry, investigations with heat conduction welding and deep penetration welding were performed. Bead-on-plate welds were carried out on stainless steel AISI 304 for this purpose using a disc laser and a remote welding system. Argon was used as shielding gas. The interaction between Reynolds number, geometrical parameters and welding/flow direction was considered. The findings were proved by transferring the results to a complex weld seam geometry (C-shape).

Trajectory Extrapolation for Manual Robot Remote Welding

This article describes an algorithm for the online extrapolation of hand-motion during remote welding. The aim is to overcome the spatial limitations of the human welder’s arms in order to cover a larger workspace with a continuous weld seam and to substantially relieve the welder from strain and fatigue. Depending on the sampled hand-motion data, an extrapolation of the given motion patterns is achieved by decomposing the input signals in a linear direction and a periodic motion component. An approach to efficiently determine the periodicity using a sampled autocorrelation function and the subsequent application of parameter identification using a spline function are presented in this paper. The proposed approach is able to resemble all practically relevant motion patterns and has been validated successfully on a remote welding system with limited input space and audio-visual feedback by an experienced welder.

The Advances and Perspectives in Using Medical Informatics for Steering Surgical Robots in Welding and Training of Welders Applying Long-Distance Communication Links

This paper discusses various challenges in remote welding with a surgical robot equipped with a digital camera used to observe the welding zone, in particular the difficulty in detecting the boundaries of the weld pool. The difference in the processing of the real image by the human brain is discussed in comparison with the image in the form of a film from a digital camera. In addition to the need of performing the second derivative of the image in real-time, three models of human recognition of an image were discussed, one of which was already studied by researchers from Cambridge, UK. The concept of melting the base material by bending the weld pool with the pressure of non-ionized arc gases and the American implementation of the measurement of the third dimension of the weld pool and determining the weld penetration by electronics of the welding machine are discussed. Desired movement trajectories of the electrode tip based on the physics of the welding arc and welding technology are presented along with difficulties in teaching the movements to welding trainees. Basics of the neural model of the brain with the vector model of artificial intelligence are also presented.