Product Code: ICA11_902

A Comparative Study of 3D Laser Surface Modification and the Humping Phenomenon
Authors:
Caroline Earl, The University of Cambridge, TWI Ltd.; Cambridge Great Britain
Paul Hilton, TWI Ltd.; Cambridge Great Britain
Jon Blackburn, TWI Ltd.; Cambridge Great Britain
Bill O'Neill, The University of Cambridge; Cambridge Great Britain
Presented at ICALEO 2011

Surfi-Sculpt® is a three dimensional surface modification technique that enables functional features to be formed from a substrate material by repeated swipes of a highly focused power beam. Similar characteristics to the humping weld instability phenomenon have been observed in the Surfi-Sculpt® process and it has been proposed that the processes may be related; however, in Surfi-Sculpt® the heat input is distributed over a longer duration and at critical time intervals when compared to conventional high speed welding. This work identifies how the Surfi-Sculpt® technique can be compared with previously published work on humping parameters and theories. Surfi-Sculpt experiments were carried out between 400 to 700mms-1 within the range of published weld humping speeds of 20 to 1500mms-1. A single mode fibre laser operating between 200-250W was used in this work and the beam was manipulated by an optical scanning system. High speed imaging with dual 500W laser illumination was used to compare the two processes and gain a greater understanding of the parameter to feature shape relationships and the theory involved in the material movement.