Optimization of powder catchment efficiency for industrial laser cladding processes

Abstract

Laser clad overlays provide enhanced corrosion resistance and wear performance to components across a wide range of industries. Powder fed laser processes provide flexibility in material selection, however have traditionally yielded lower material usage efficiency (60–80%) compared to wire fed processes. A general model was developed to predict powder catchment efficiency based on the overlap between the molten pool and powder cloud distribution. Mathematical techniques of asymptotic analysis and blending were used to obtain closed-form expressions relating tabulated material properties and the key process inputs with the critical melt pool dimensions of leading length (xf) and maximum width (y m). An improved experimental technique was implemented to measure the powder cloud distribution, a key process input which previously was not well understood. For baseline cladding conditions, melt pool dimensions were smaller than the powder cloud leading to catchment inefficiency. A custom laser optics module was designed to enable adjustment of the relative position of the melt pool and powder cloud independently from other process parameter changes. Combining optimized parameters with a shift of 1mm, catchment efficiency >90% has been achieved and sustained in production cladding operations. This work is part of a broader program at Apollo-Clad, using simple, accurate, and fast analytical modelling techniques to generate engineering design rules for laser-based processes.