TWI Frequently asked questions
The use of lasers for welding has some distinct advantages over other welding techniques. Many of these advantages are related to the fact that with laser welding a 'keyhole' can be created. This keyhole allows heat input not just at the top surface, but through the thickness of the material(s). The main resultant advantages are detailed below:
Speed
Laser welding is a very fast technique. Dependent on the material, for thin sections, speeds of many metres a minute can easily be achieved. They are, therefore, extremely suited to working in high productivity automated cells. For thicker sections, productivity gains can be made as the laser keyhole process can weld in a single pass what would require multiple passes with conventional techniques. The optical fibre delivered beam from Nd:YAG lasers particularly can easily be remotely manipulated by multi-axis robotic delivery.
Deep, narrow welds
Laser welding allows welds to be made with a high aspect ratio (depth to width). Laser welding, therefore, is feasible for joint configurations that are unsuitable for many other (conduction limited) welding techniques, such as stake welds. For example, this could allow smaller flanges to be used compared to parts made with resistance spot welding.
Low distortion
Lasers produce a highly concentrated heat source, capable of creating a keyhole. Consequently, laser welding transmits less heat into the material and samples distort less than those welded with most other techniques. Another advantage resulting from the low heat input is narrow heat affected zones giving less thermal damage to the parent material.
Suitable for a range materials and thicknesses
With lasers, many different materials can be welded, both metallic and non-metallic. Furthermore, the thickness of the material can be anything from under a millimetre to around 30mm for most steel types.
Non-Continuous welding
With lasers, spot or stitch welds can be made as easily as continuous welds.
Versatile tool
Apart from welding, with a few adjustments, a laser source can be used for many other materials processing applications, for example cutting, surfacing, heat treatment and marking, and also for more complex techniques such as rapid prototyping.
