Laser welding in the automotive industry

As a result of the increasing electrification of mobile drives, the use of modern copper and aluminum materials is steadily gaining in importance. Due to their high electrical conductivity, they are excellently suited for the transmission of electricity. Conventional joining processes such as gas-shielded metal arc welding (GMAW) or tungsten inert gas welding (TIG) are more and more reaching their limits in view of the advancing miniaturization of components and parts as well as increasing quality requirements for joined joints.

Laser beam welding, characterized by the concentrated energy input into the component, offers a superior process for the production of similar (e.g. copper-copper) and dissimilar (e.g. aluminum-copper) welded joints. By means of high-performance laser beam sources, high power densities can be realized, resulting in joints with excellent weld seam quality even on highly reflective and coated material surfaces.

The advantages of laser beam welding

Material

• Joining of highly reflective and coated materials
• Joining of thin foils from a few micrometers thickness to thick sheets

Process

• Cost-effective joining processes that can be fully automated
• Heat input control via process parameters to reduce intermetallic phases
• Avoidance of process spatter during welding
• Use of image recognition software for continuous welding process optimization

Component properties

• Low thermal stress on the component during the welding process
• Metallic joints with high electrical conductivity, e.g. low transition resistances, optimal contacting
• Production of components with long service life and optimum joint geometry while preserving important material properties, e.g. mechanical stability under vibration and acceleration

Application examples

• Batteries: Cell housings, cell connectors, current collectors, contact and bus bar connections
• Electric motors: Hairpins, shunts, cables, copper strands, cable connectors
• Peripherals: electrical contacts, power electronics

Modern lightweight construction, based on an intelligent mix of materials with high strength (e.g. aluminum, steel, non-ferrous metals, fiber composites), places high demands on joining technology. Material-adapted laser beam welding processes and high-performance laser beam sources with wavelengths from 450 to 1,080 nanometers enable lightweight structures with very good weld seam properties. This ensures the best possible compromise between safety and weight. In order to meet the goal of high-strength, corrosion-resistant welded joints, we rely on filler materials, thermal seam pre-treatments and post-treatments as well as state-of-the-art scanner optics for 2D and 3D oscillation processes. 

Advantages of laser beam welding

Material

• Durable, highly loadable and cost-effective joints for industrial use
• Joining of high-strength, difficult-to-weld aluminum and high-alloy steel materials, e.g. 16MnCr5, 65NiCrMo3, sintered and cast materials
• Joining of thin sheets (tenths to a few millimeters thick) up to wall thicknesses of 4 to 8 millimeters
• Use of transition joints, e.g. roll plated strips of different alloys  
  

Process

• Highly efficient (short cycle time, low unit costs) and fully automated joining processes
• Heat input control via process parameters to reduce intermetallic phases
• No filler materials necessary for steel materials with high carbon equivalent
• Avoidance of process spatter during welding
• Seam detection and process monitoring by inline and offline sensors, e.g. optical image recognition, plasma detection, acoustics, and ultrasound

Component properties

• Tight joints for transferring static, cyclic and dynamic crash loads
• Components with long service life and optimum T-joint geometry, e.g. mechanical stability during vibration and acceleration

Application examples

• Drive shafts, transmission shafts, gears, differentials, engine components, tools
• Structural components, housings, sheet metal connections (patchwork and tailored blanks)