Laser Cladding

Laser cladding is a modern technology whose uses include, for example, the creation of protective coatings to reduce wear and corrosion on engine parts and tools. The process is now also often used for the purpose of Additive Manufacturing to fabricate whole parts layer-by-layer. The aircraft and automotive industries are examples of industries in which it is much employed. This account considers the theory of a number of aspects of the process in detail. The first to be studied is the interaction of the laser beam directly with the powder that is being deposited; the effects of gravity, beam shadowing, and particle heating are investigated. This is followed by a discussion of themechanisms by which the particles adhere to the surface of the work piece and are absorbed into it. In order to understand the process, a study of the melt pool and the associated temperature distribution is necessary; it is then possible to infer the final bead geometry. An inevitable consequence of a thermal process such as laser cladding is the induced thermal stress and resulting distortion of the work piece. The fundamentals are discussed, a numerical model presented and in addition a simple heuristic model is given. The use of induction-assisted laser cladding as a means of preventing the formation of cracks is discussed.