2010 is the 50th anniversary of the laser and this issue of Research Spotlight looks at the use of lasers in manufacturing, highlighting some of the current developments in cutting, welding, drilling, and other machining applications.
Laser Hybrid Welding
Laser welding has been utilised for joining for a number of years thanks to its high power density and small heat affected zone. It is a very precise process however, requiring good joint preparation and alignment and cannot be performed manually. By combining these properties with a more traditional arc-welding process such as gas metal arc (GMA) "laser hybrid welding" greater positioning flexibility can be allowed as the arc welding process supplies molten metal to fill the joint and the effect of the laser increases the welding speed possible. In theory, any laser source can be used with any arc source, including MIG/MAG, TIG or plasma and many combinations are available.
Laser Direct Metal Deposition
At TWI in the UK, there are a number of laser DMD systems which permit materials such as Waspalloy, Titanium and metallic glasses to be deposited onto suitable substrates as a direct manufacturing process or as a repair technique. Typical applications include the repair of turbine blade tips and mould tools, as well as the production of specialist components such as medical implants. By varying the material composition as it is deposited, functionally graded components are also possible
Laser Surface Treatment
Again at TWI, research is underway into the ways in which lasers can be utilised to modify the surface of a component or material. This modification can be through hardening, glazing, melting with the addition of a powder or wire feed or even a highly specialised surface sculpting process to produce physical surface modification. Typical applications include hardening valve seats and bearing surfaces and tribological modification.
Swinburne University are also active in the use of lasers for surface treatment and deposition.
Laser-Assisted Punching
The application of a laser to assist in the punching process reduces the force required to complete the operation and also improves the quality of the punched component. This process modification also permits punching to be used on non-traditional materials such as Titanium. Fraunhofer IPT in Aachen also report that warping and noise levels are also reduced.
Lasers in Composites
Lasers are now being utilised to speed up the laying of carbon fibre composite tapes in aerospace and other applications. The addition of the laser promotes curing of the resin component of the prepreg tape and eliminates the need for a post-forming curing cycle.
Laser Assisted Riveting
Work underway between CAST CRC and Henrob is looking to expand the use of self-piercing riveting systems for use with low ductility materials, primarily Magnesium. This material, either as a Mg-Mg sheet metal joint, or in combination with Aluminium, is of great interest in the automotive industry. Conventional self-piercing riveting operations combined with Magnesium's poor ductility at room temperature cause cracking of the Magnesium on the rear side. Laser preheating of the magnesium material improves the joint quality significantly and this points the way to a new market for this Australian developed technology.
Laser Assisted Milling
When milling Titanium materials, heat build-up at the tool tip accelerates tool wear and results in a poor surface finish. One potential solution for this is currently being trialled by CAST CRC in conjunction with industry partners. LMCut uses a laser beam directed in front of the cutting tool, allowing the material to be cut with greater ease. Initial trials show a reduction in cutting forces and increased tool life. Since their inception 50 years ago, laser have been used as the primary tool in processes such as cutting and surface treatment, but new hybrid solutions continue to be explored which combine traditional processes with the advantages of lasers to increase speed, reduce waste, increase quality and even to improve the applicability of a particular process into non-traditional materials.
If you would like any further information on any of the applications described here, or would like to discuss the application of lasers please contact Dr Sara Eastwood on 3364 0764 or sara.eastwood@qmisolutions.com.au.