Seam geometry manipulation by oscillation amplitude adjustment in the LDNA process

The Laser assisted double wire with non-transferred arc surfacing process (LDNA) is based on an electric arc to melt the filling wires and a laser beam to shape the melt pool. This work investigates the welding seam characteristics for different oscillation amplitudes with differing laser output power. Therefore, three laser powers between 1,000 W and 2,000 W in combination with a power of 4,800 W brought by the arc are investigated regarding the resulting seam geometry and the dilution ratio. A linear oscillation pattern is used with a constant oscillation frequency of 10 Hz. The investigations are conducted using AISI 316L welding wires of 1.2 mm in diameter and sandblasted AISI 1024 plates of 20 mm thickness. Cross-sections are analyzed to investigate the occurrence of cracks and pores as well as to determine the dilution ratio with the base material. The welding seam geometry is measured with a laser scanning microscope Keyence VK-X1100. The topology of adjacent welding seams is examined showing an increase of the welding seam width with an increase of the oscillation amplitude and the laser output power. Thus, a higher maximal seam width can be applied by adjusting the laser power.