A comparative investigation of the efficacy of CO₂ and high-power diode lasers for the forming of EN3 mild steel sheets

Abstract

A comparative investigation of the e V ectiveness of a high-power diode laser (HPDL) and a CO 2 laser for the forming of thin-section EN3 mild steel sheet has been conducted. The buckling mechanism was identi®ed as the laser forming mechanism responsible for induced bending. For both lasers it was found that the induced bending angles increased with an increasing number of irradiations and high laser powers, while decreasing as the traverse speed was increased. Also, it was apparent from the experimental results that the laser bending angle was only linearly proportional to the number of irradiations when the latter was small due to local material thickening along the bend edge with a high number of irradiations. Owing to the mild steel's greater beam absorption at the HPDL wavelength, larger bending angles were induced when using the HPDL. However, under certain conditions the performance of the CO 2 laser in terms of induced bending angle was seen to approach that of the HPDL. Nevertheless, similar results between the two lasers were only achieved with increasing irradiations; thus it was concluded that the e ¤ cacy of the HPDL was higher than that of the CO 2 laser insofar as it was more e ¤ cient. From graphical results and the employment of an analytical procedure, the laser line energy range in which accurate control of the HPDL bending of the mild steel sheets could be exercised e ¤ ciently was found to be 53 J/mm < P=v < 78 J/mm, while for the CO 2 laser the range was 61 J/mm < P=v < 85 J/mm.

Making Light Work of Metal Bending: Laser Forming in Rapid Prototyping

“…The early reports focused on using high power (>1 kW) lasers [40,60,61,70,71,[98][99][100][101][102][103], as the intent was to bend large sheets as part of the ship building process [35]. The laser forming of thinner substrates enables the use of lower power (<100 W) lasers, such as those found in commercial metal marking laser systems [57,63,67,76,85,88,93,104].…”

Review about laser coating of aluminium alloys

“…Li [18] menciona la ventaja del lá-ser de diodo frente al de CO 2 y Nd:YAG, en la soldadura de materiales, debido a que la longitud de onda más corta implica una mejor absorción del haz. Lawrence [19] concluye en su investigación comparativa entre láser de CO 2 y el HPDL, que la eficacia del láser de diodo es mayor que la del láser de CO 2 . Iwatani et al [20] realizan recubrimientos de aleaciones de aluminio, utilizando tecnología láser de diodo y observan que con menor aportación de energía que la utilizada con láser de CO 2 se obtienen cordones de recubrimiento estables.…”

“…Existen estudios, como el de Lawrence [19] que, en su investigación comparativa entre láser de CO 2 y lá-ser de diodo, concluye que la eficacia del láser de diodo es mayor que la del láser de CO 2 . La eficiencia de la conversión de la energía eléctrica en óptica, alcanza valores máximos, del 50 %, en los láseres de diodo de alta potencia, aunque la eficiencia teórica de un láser de diodo es del 90 %.…”

Effects of Scanning Schemes on Laser Tube Bending

“…The application of direct diode lasers into laser forming of plates has also been investigated. Lawrence [5] conducted a comparative investigation of the efficiency of CO 2 laser and diode laser in the forming of mild steel sheets. Lopez, et al [6] applied a diode laser in the forming of stainless steel, AlMg3 and St 14 sheets and investigated the correlation between bending angle and parameters such as path feed rate, number of irradiations, sheet materials and sheet thickness.…”