Nanosecond laser texturing for high friction applications

TLDR

High‑friction laser‑textured surfaces can reduce tightening forces in large engines and secure precision fittings. A 1064‑nm nanosecond Nd:YAG fibre laser was used to texture various steels in a hexagonal pulse pattern with adjustable overlap and energy to produce high‑friction surfaces. Friction tests show that pulse energies around 0.8 mJ and overlaps above 50 % yield static friction coefficients >0.5, with increased surface hardness from metal‑oxide formation correlating with higher friction.

Abstract

A nanosecond pulsed Nd:YAG fibre laser with wavelength of 1064 nm was used to texture several different steels, including grade 304 stainless steel, grade 316 stainless steel, Cr–Mo–Al 'nitriding' steel and low alloy carbon steel, in order to generate surfaces with a high static friction coefficient. Such surfaces have applications, for example, in large engines to reduce the tightening forces required for a joint or to secure precision fittings easily. For the generation of high friction textures, a hexagonal arrangement of laser pulses was used with various pulse overlaps and pulse energies. Friction testing of the samples suggests that the pulse energy should be high (around 0.8 mJ) and the laser pulse overlap should be higher than 50% in order to achieve a static friction coefficient of more than 0.5. It was also noted that laser processing increases the surface hardness of samples which appears to correlate with the increase in friction. Energy-Dispersive X-ray spectroscopy (EDX) measurements indicate that this hardness is caused by the formation of hard metal-oxides at the material surface.