Laser Beams for Surface Engineering

Laser beams can alter the surface properties of materials with great precision, primarily because of the inherent flexibility of delivery of the laser light. Originally, much of the work on surface engineering was performed with CO₂ lasers, but today the more efficient diode, fibre and disc lasers are also employed. The latter lasers also have the added advantage that their beams can be delivered via optical fibres. Surface engineering applications for laser include:-

Transformation or sheet hardening, in which the surface is not melted	Selectively laser hardened rotating bearing surface on manually operated clamp
Glazing, homogenisation, refining and polishing, where the surface is melted	Cam shaft
Melting with the addition of material, eg powder or wire feed, as in cladding	Laser cladding on the edge of a blade used in a wood pulping machine
Laser direct metal deposition (DMD) for component repair	Laser direct metal deposition of metallic powder
Modification of the surface of material by selective and controlled movement of melted material, using Surfi-Sculpt®	Laser induced Surfi-Sculpt on a titanium substrate

Equipment capabilities

Several lasers suitable for surface engineering, including Nd:YAG, fibre, CO², and diode are available at TWI. Very precise Cartesian gantry 3D manipulation of the focused laser beam is available with the CO² laser, while the other laser beams are manipulated using articulated arm robots. For transformation hardening, lasers are particularly useful for the selective hardening of particular features as a component that might require for example enhanced wear properties.

Applications

Lasers offer many benefits for surface engineering, including localised treatment, low thermal distortion, control of treatment depth and the ability to address complex shapes. Typical applications of laser surfacing include:

For more information please contact: lasers@twi.co.uk