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The significance of deposition point standoff variations in multiple-layer coaxial laser cladding (coaxial cladding standoff effects)

Research output: Contribution to Journal/MagazineJournal articlepeer-review

<mark>Journal publication date</mark>05/2004
<mark>Journal</mark>International Journal of Machine Tools and Manufacture
Issue number6
Number of pages12
Pages (from-to)573-584
Publication StatusPublished
<mark>Original language</mark>English


Direct laser deposition (DLD) is an additive manufacturing process that builds up a part layer-by-layer by fusing metal powder to a solid substrate. A coaxial laser and powder delivery head is commonly used, and here a critical process variable is the standoff distance between the nozzle and the material deposition point. This contribution investigates the role of this variable and the effect that it has on the final part geometry. The experimental results show that good layer consistency can, in fact, be obtained with no movement of the substrate between layers for more than 20 layers, or 10 mm under tested conditions, and that poorer results are obtained by regular movement of the substrate by a badly chosen constant amount. A theoretical analysis of the situation establishes a method to estimate melt pool size using an analytically calculated temperature near the heat source. Based on this, simple heat and mass flow models are established to allow some of the results to be explained. (C) 2004 Elsevier Ltd. All rights reserved.