High-Precision Adjustment of Welding Depth during Laser Micro Welding of Copper Using Superpositioned Spatial and Temporal Power Modulation

Abstract

For joining metallic materials for battery applications such as copper and stainless steel, laser beam micro welding with beam sources in the near-infrared range has become established in recent years. In laser beam micro welding, spatial power modulation describes the superposition of the linear feed motion with an oscillating motion. This modulation method serves to widen the cross-section of the weld seam as well as to increase the process stability. Temporal power modulation refers to the controlled modulation of the laser power over time during the welding process. In this paper, the superposition of both temporal and spatial power modulation methods is presented, which enables a variable control of the weld penetration depth. Three weld geometries transverse to the feed direction are part of this investigation: the compensation of the weld penetration depth due to the asymmetric path movement during spatial power modulation only, a W-shaped weld profile, and a V-shaped. The weld geometries are investigated by the bed on plate weld tests with CuSn6. Furthermore, the use of combined power modulation for welding tests in butt joint configuration between CuSn6 and stainless steel 1.4301 with different material properties is investigated. The study shows the possibility of precise control of the welding depth by this methodology. Depending on the material combination, the desired regions with maximum and minimum welding depth can be achieved by the control of local and temporal power modulation on the material surface.

Controlling the weld penetration depth of laser beam micro welding by using an iterative learning approach

“…The difference to T Process results from T OffsetStart = 30 ms and T OffsetEnd = 35 ms. Due to the complex course of the data for the processes with spatial power modulation, the presented range is limited to the time interval between 110 ms and 190 ms. Here, a verification is made whether the use of the iterative learning control makes it possible to compensate for effect of the non-uniformity of the weld penetration depth when using spatial power modulation [13].…”

Quasi-Continuous Wave Pulsed Laser Welding of Copper Lap Joints Using Spatial Beam Oscillation

“…Good quality joints without any crack formation were observed due to low-stress generation during laser beam welding. Hummel et al [26] used spatial and temporal power modulation to control the weld penetration in laser beam welding of copper. They concluded that the position of minimum and maximum laser power is critical for the adjustment of weld seam geometry.…”