Rapid tooling by laser cladding

Abstract

A laser cladding process has been developed for building up three dimensional (3D) metallic objects for use as tooling and engineering components. The process can reduce the lead-time and cost of fabricating metal parts, especially those made of super-alloys, and offers new opportunities for metallurgical and mechanical design of components.The cladding system consists of a CO2 laser interfaced to a CNC XYZ stage and a powder feeding unit with a specially designed co-axial feeding nozzle. Clad tracks were overlapped horizontally and vertically at selected areas to form 3D objects. To achieve good mechanical properties for tooling applications, we investigated laser 3D cladding of nickel- and copper-based alloys. Unlike selective laser sintering, pure metal powders were used to obviate the de-binding and infiltration secondary processes. To generate a near net shape metal part with good surface finish and feature details, a fine laser beam of about 240 μm in diameter at a maximum beam power of 200 watts was used for the cladding process. A variety of metallic objects were produced with good dimensional accuracy, full mechanical strength, and a surface finish of 17 μm (Ra).A laser cladding process has been developed for building up three dimensional (3D) metallic objects for use as tooling and engineering components. The process can reduce the lead-time and cost of fabricating metal parts, especially those made of super-alloys, and offers new opportunities for metallurgical and mechanical design of components.The cladding system consists of a CO2 laser interfaced to a CNC XYZ stage and a powder feeding unit with a specially designed co-axial feeding nozzle. Clad tracks were overlapped horizontally and vertically at selected areas to form 3D objects. To achieve good mechanical properties for tooling applications, we investigated laser 3D cladding of nickel- and copper-based alloys. Unlike selective laser sintering, pure metal powders were used to obviate the de-binding and infiltration secondary processes. To generate a near net shape metal part with good surface finish and feature details, a fine laser beam of about 240 μm in diameter at a maximum beam power of 200 watts wa...