Strain Gauge Analysis of Laser Forming

JOURNAL OF LASER APPLICATIONS VOLUME 15, NUMBER 4, PAGES 225 - 232
NOVEMBER 2003

S. P. Edwardson, K. G. Watkins, G. Dearden, P. French, J. Magee*
Laser Group, Department of Engineering,
The University of Liverpool, Liverpool, L69 3GH, United Kingdom
(*Currently at: National Centre for Laser Applications, NUI Galway, Ireland)

Laser forming has become a viable process for the shaping of metallic components, as a means of rapid prototyping and of adjusting and aligning. The laser forming process is of significant value to industries that previously relied on expensive stamping dies and presses for prototype evaluations. This investigation aims to complement the considerable amount of work already completed on two-dimensional laser forming, offering an insight into the mechanical behaviour of a part during the process using a strain gauge analysis technique. The investigation was performed on Mild Steel CR4 sheet using a CO2 laser source. It includes empirical investigations to determine optimum processing parameters using the temperature gradient mechanism, thermocouple analysis to locate ideal strain gauge placement for temperature compensation and strain gauge analysis of the transverse localised strains at a number of locations on the surface of the sheet during single and multi-pass laser forming. The results of the investigation demonstrate the relative complexity of the process even during a simple straight-line bend and that a residual strain component remains in the sheet after processing.

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