Investigation of striation formation in thin stainless steel tube during pulsed Nd : YAG laser cutting process by numerical simulation

The formation of a striation pattern in a thin stainless steel tube was inv estigated by numerical simulation during a pulsed Nd:YAG laser cutting proc ess. The simulated results were compared with the experimental results, whi ch were performed under the same conditions for simulation. The simulated r esults showed good agreement with the experimental results. Although the fo rmation of the striation pattern was influenced by various laser parameters , the laser power density had become the most important factor in the forma tion of striation patterns, since the laser power density is the most influ ential in the heating of metal, and the striation formation is caused by th e ejection of molten metal and evaporation during laser cutting process. Al though a high power density resulted in clear regular striation patterns, r elatively low power density caused the formation of a hot spot, which hinde red the formation of regular striation patterns and caused less striation. The numerical simulation calculations can be used to predict the shape of s triation patterns and to offer a way to provide a smooth cut wall.