Surface cleaning technologies for the removal of crosslinked epoxide resin

This study provides details of the use of laser ablation and sodium hydride cleaning processes for the removal of crosslinked epoxide and other residues from resin transfer moulding (RTM) tool substrates, as used in the aerospace industry. The requirement for removal of such contamination is so that the mould can be re-used, following the subsequent application of an external release agent. These tools are, typically, fabricated from steel, nickel or CFRP composite materials; this paper focuses on the use of nickel substrates. The requirement to clean large surface areas quickly to satisfy commercial restraints, compromises the degree of absolute cleanliness that can be obtained. However, in applications where cleaning time is not a constraint, laser cleaning can be a very gentle and efficient process; typically Nd:YAG lasers find application in this area. In contrast, high-power lasers are desirable for industrial scale applications where large areas need to be cleaned quickly. In this instance pulsed CO2 lasers can be used. The use of sodium hydride was also found to be highly successful in removing crosslinked organic contamination providing that suitable hard rinse and drying operations were also carried out.