Micromelting for Laser Micro Polishing of Meso/Micro Metallic Components

The relative surface accuracy (surface roughness/feature size) of meso/micro parts fabricated by emerging meso/micro manufacturing processes is generally worse than that of macro parts fabricated by conventional processes. Meso/micro parts have unique tribology issues and surface roughness strongly impacts their performance, hence there is a demand for effective polishing of their complex shapes. A laser micro polishing method based on rapid surface micromelting is described. To develop a fundamental understanding of the underlying processes, a nickel sample was fabricated using silicon-based microfabrication and electroplating techniques. Results demonstrating the effectiveness of laser polishing using a pulsed 1064 nm Nd:YAG laser are presented. These results show that brief (200–300 ns) laser pulses can significantly improve the sample surface roughness (Ra). Additionally, by examining surface profile data in the spatial frequency domain it is clear that using pulses (up to 300 ns), laser polishing can effectively remove surface roughness features greater than 200 mm⁻¹ in spatial frequency.