TWI Industrial Member Report Summary 666/1999
I A Jones and P A Hilton
Background
The carbon dioxide gas laser has dominated commercial laser materials processing applications for some time. The convenience of its high power capability is limited by the fact that the laser beam has to be brought to the workpiece through air, via a series of mirrors. For large scale applications or complex geometries, this often means large, heavy duty, highly accurate, moving mirror guidance systems. In addition, the high reflectivity of some metals to the carbon dioxide laser wavelength limits available weld penetration or cutting speeds.
The possibility of using the power available from a gas laser and combining this with the flexible and advantageous beam delivery offered by optical fibres is commercially interesting. With any significant transmission, passing the carbon dioxide laser's 10.6µm light through an optical fibre is currently not viable. The possibility of using the 5µm wavelength of the carbon monoxide gas laser to propagate down an optical fibre was seen to be more realistic, and these topics have been addressed in a recently completed EUREKA project. In addition to the benefit of high power fibre delivered laser power, the carbon monoxide laser was also thought to be able to provide materials processing benefits, due to its lower wavelength.
Objectives
The objectives of the work undertaken using a fast axial flow carbon monoxide laser were to:
- Assess the welding performance of the 5µm CO laser wavelength on C-Mn and aluminium alloy.
- Assess the cutting performance of the 5µm CO laser wavelength on C-Mn steel, stainless steel and aluminium alloy.
- Comment on the industrial applicability of high power CO lasers.