Parametric study on laser marking of circular shape on stainless steel 304

Abstract

Laser marking is one of the operations performed by laser with an aim to identify products, components, etc., so that they can be easily traced with information. The multi diode pumped fibre laser with ytterbium doped as a lasing medium, was used to mark a circular shaped image. The paper aimed to study the influence of process parameters such as laser power, pulse frequency, scanning speed, duty cycle and transverse feed on responses such as mark intensity, circularity and surface roughness value (Ra, μm). The range of process parameters involved were transverse feed of 4-14 μm per laser stroke, laser power of 7.5-17.5 W, pulse frequency of 50-60 kHz, duty cycle of 20-40% and scanning speed of 5-25 mm/s. Experimental work was carried out without the supply of assist gas pressure and laser marking process was done by scanning the fibre laser for single pass. Experimental results revealed that for better value of mark intensity, circularity and surface roughness value (Ra) of circular shaped marked image, the process parameters such as laser power of 12.5 watt (W), pulse frequency of 50 kHz, duty cycle of 30% and scanning speed of 5 mm/s should be selected.