251 Study of Metal Forming Using Shock Wave Generated by Femtosecond Laser Irradiation

Thin-sheet-metal bending by laser peen forming with femtosecond laser

“…E was 150 J constant in air, and was 100 J constant in water. Comparatively close  had been obtained by these irradiation conditions in preparatory experiments performed by Sagisaka (2008).…”

“…Edwards et al (2007) have adopted an absorptive coating. Sagisaka (2008) has confirmed that water film sometimes increases the bending efficiency with femtosecond laser also. However, shorter pulse laser is easy to induce shock waves.…”

“…The authors aimed to develop an accurate thin-sheet-metal bending method and apply it to micro parts production such as magnetic head suspension of hard disk drive. Sagisaka (2008), one of the authors, has proposed thin-sheetmetal bending by laser peen forming with femtosecond laser and has investigated its fundamental forming properties. However, this method requires a long processing time.…”

Mold-free fs laser shock micro forming and its plastic deformation mechanism

“…We also quantitatively evaluated the peak pressure of a fs laserinduced shock wave when it was used for confined ablation (where a transparent confining layer is used to confine the expansion of the ablated plasma) and we found that, even with a very low laser fluence, the peak pressure could reach several tens of GPa [15], which is much higher than the dynamic yield strengths of most metals. So, fs laser-induced shock waves have been used in processing materials and fabricating parts [10,[15][16][17][18][19][20]. Compared to a ns laser, a fs laser has unique advantages when performing micromachining and micro manufacturing, including higher precision and the lack of a heat-affected zone [21,22].…”

“…Compared to a ns laser, a fs laser has unique advantages when performing micromachining and micro manufacturing, including higher precision and the lack of a heat-affected zone [21,22]. Besides, due to the ultrashort loading time, the total shock effect induced by a fs laser is not large enough to blow away microparts or burst thin metal targets [19,20]. All these properties make fs lasers very suitable for microforming.…”