Product Code: ICAL08_2004

Influence of Assist Gas in Fibre Laser Cutting of Aluminum-Copper Alloy
Authors:
Antonio Riveiro, Universidade De Vigo; Vigo Spain
Felix Quintero, Universidade De Vigo; Vigo Spain
Antti Salminen, Lappeenranta University of Technology; Lappeenranta Finland
Fernando Lusquis, Universidade De Vigo; Vigo Spain
Juan Pou, Universidade de Vigo; Vigo Spain
Veli Kujanpaa, Lappeenranta University of Technology; Lappeenranta Finland
Presented at ICALEO 2008

Fibre laser cutting is an emerging field in laser materials processing. This new generation of high power solid state lasers offers a lot of advantages as compared to traditional lasers sources in the laser cutting field. The combination of high output power, high brightness, reduced focal spot, and low divergence of the laser beam in these sources is extremely interesting for cutting applications. Several works have shown that fibre laser cutting enables processing with higher production rates than in the processing assisted by means of CO2 laser, reaching similar levels of quality when thin sheets are cut. However the quality of the cuts is substantially worsened with the increase in thickness due to the difficulty in the extraction of the molten material by the assist gas jet. Moreover, the high brightness of these sources modifies the physical mechanisms which take part in the cutting process and an elevated recoil pressure makes cut quality worse. In this work, an attempt to improve cut quality in the fibre laser cutting process was accomplished. An off-axis supersonic nozzle in conjunction with a high power fibre laser was utilized in order to process an aeronautic aluminium-copper alloy such as the 2024-T3 alloy (3 mm in thickness). A systematic study on the influence of several parameters related to assist gas delivery system on the cut quality was carried out. Microstructural characterization, grain morphology, kerfs dimensions and surface finish of the performed cuts were studied.