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Laser forming is fast emerging as a viable means for the shaping of metallic components, as a means of rapid prototyping and of adjusting and aligning. Relevant industry sectors include aerospace, automotive, and microelectronics. In contrast with conventional forming techniques this method requires no mechanical contact and hence offers many of the advantages of process flexibility associated with other laser manufacturing techniques such as laser cutting and marking. This article reviews the mechanisms involved and the main models proposed in laser forming and presents an overview of the main applications currently developed. An assessment is made of the potential for future development of this new technology.

In the current work ablation of metal targets in air with femtosecond laser pulses is studied. The laser pulses used for the study were 775 nm in wavelength, 150 fs in pulse duration and the repetition rate was 100 Hz. Ablation thresholds have been measured for a number of metals including stainless steel (0.1600 J/cm 2 ), niobium (0.1460 J/cm 2 ), titanium (0.1021 J/cm 2 ) and copper (0.3529 J/cm 2 ). The ablation depth per pulse was measured for laser pulse fluences ranging from the ablation threshold (of most metals) ~ 0.1 J/cm 2 up to 10 J/cm 2 . It has been shown previously that there are two different ablation regimes. 1 In both cases the ablation depth per pulse depends logarithmically on the laser fluence. Whilst operating in the first ablation regime the ablation rate is low and is dependant on the optical penetration depth, . -1 . While in the second ablation regime the ablation rate is greater and is characterized by the "electron heat diffusion length" or the "effective heat penetration depth", l. In the present study good qualitative agreement in the ablation curve trends was observed with the data of other authors, e.g. Nolte et al (1997). 1

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