Principle And Application of Laser Oscillation Welding

 Application background Laser oscillating welding technology was born out of the urgent need for welding quality and efficiency in modern manufacturing. Traditional welding technology has deficiencies in precision, strength and complex structure, which has prompted the rapid application of laser welding in various fields. However, it still has defects such as pores and cracks, and has limitations in welding dissimilar materials and complex-shaped parts. It is difficult to meet the stringent requirements of high-end fields such as aerospace and automobile manufacturing, affecting product quality, safety, production efficiency, etc., and increasing the manufacturing cost of enterprises. Against this background, laser oscillating welding technology came into being.

What is laser oscillating welding? Laser oscillating welding is also called laser scanning welding. The control system can be used to regulate the oscillation mode, frequency and amplitude to achieve the oscillation of the laser and the planning of the path.

                 Schematic diagram of laser oscillation welding device

Laser oscillation welding molten pool:

① Similar to ordinary laser welding, when laser oscillation welding starts, the laser energy is absorbed by the surface of the base material, causing the surface temperature of the material to rise rapidly. Due to the high energy density of the laser, the surface temperature of the material can reach the melting point in a very short time.

② As the material melts, the liquid metal begins to gather under the combined action of surface tension and gravity. During the laser oscillation process, the laser beam continuously scans an area on the surface of the base material, causing the metal in this area to continue to melt, and the amount of liquid metal continues to increase, thus gradually forming a molten pool.

Laser oscillating welding pool

 Gap width and fusion depth In traditional laser welding, the laser beam energy is highly concentrated, and the molten pool formed is relatively narrow. In order to avoid welding defects, strict requirements on the gap are required, and high-precision processing and assembly are required, which increases costs and production cycles. Usually the gap is controlled to be less than 10% of the plate thickness.

Maximum gap between conventional laser welding and swing laser welding

Welding defect control and thermal stress relief: Laser beam oscillation redistributes the heat of the molten pool, reducing the temperature gradient and thermal stress concentration. By swinging the beam, the probability of crack initiation is reduced, extending the fatigue life of the welded structure.

Grain structure optimization: When the molten pool solidifies, the oscillation promotes grain refinement and uniform growth in the heat-affected zone, forming more equiaxed crystals. Grain refinement enhances the crack resistance of the weld, while more grain boundaries hinder crack propagation and reduce crack sensitivity.

Solidification mode of laser welding a) Conventional b) Oscillating

Applications

 Application of laser oscillating welding a) Heat exchanger exterior b) Heat exchanger cross section c) Pipe angle joint  d) Battery copper components (no pores or cracks) e) Stainless steel and copper welding (dissimilar welding)