25-09-2014, 03:08 PM
Laser beam machining (LBM), state of
the art and new opportunities
1407935503-LaserBeamMachining2.pdf (Size: 658.13 KB / Downloads: 164)
Abstract
An overview is given of the state of the art of laser beam machining in general with special emphasis on applications of short and
ultrashort lasers. In laser welding the trend is to apply optical sensors for process control. Laser surface treatment is mostly used to apply
corrosion and wear resistant layers, but also for repair of engine and machine parts. In micro-machining, shorter pulses reduce heat-affected
damage of the material and opens new ways for nanometer accuracy. Even 40 years after the development of the laser there is a lot of
effort in developing new and better performing lasers. The driving force is higher accuracy at reasonable cost, which is realised by compact
systems delivering short laser pulses of high beam quality. Another trend is the shift towards shorter wavelengths, which are better absorbed
by the material and which allows smaller feature sizes to be produced. Examples of new products, which became possible by this technique,
are given. The trends in miniaturisation as predicted by Moore and Taniguchi are expected to continue over the next decade too thanks to
short and ultrashort laser machining techniques.
Laser cladding and alloying
Lasercladden is used to improve the surface quality by
applying a hard or a corrosion resistant layer on a product of
cheap or better to machine material. The common technique
is to create a shallow melt pool by a defocussed laserbeam
and supply metal powder in that pool using an inert gas flow.
Examples are shown in Fig. 5, left the cladding of a roller
wheel for sheet metal forming, centre cross section of the
wheel and right a diesel engine crankshaft.