Material Processing using Laser Induced Droplet Vaporization

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There is an increasing demand for high performance materials many of which are incompatible with conventional manufacturing processes due to their sensitivity with heat and abrasion (e.g. carbon fibre reinforced polymer (CFRP), polymers, thin films, semiconductor wafers). Surface preparation of these advanced materials is usually essential to exploiting their enhanced properties in engineering applications. This project concerns the development of a new, low temperature material processing technique using impulsive shock waves of liquid vapour as a generic manufacturing tool, called material processing by laser induced droplet vaporisation (LIDV). LIDV uses a pulsed laser to vaporise a stream of droplets to produce a succession of impacting shock waves at the surface of the component of interest. By exploiting the precision of modern droplet generation technologies with the power and control of a laser source, well-regulated impulsive forces can be achieved at a level sufficient to remove surface contaminants and/or to modify the surface mechanical properties (roughness and hardness). The project will undertake proof-of-principle experiments to establish the benefits of LIDV as a means to clean and modify the surface of CFRP. CFRP presents a particular problem since a multi-stage surface preparation process is required as all traces of surface contaminants and chemical agents that are exhumed during production must be removed before final assembly. It is expected that the LIDV process could provide more accurate and efficient surface modification of high performance materials than at present and that it will also open the door for exciting breakthroughs in peening, thin films transfer, hardening and alloying.