DESIGN CHARACTERISTICS AND DEVELOPMENT OF A NOZZLE FOR COAXIAL LASER CLADDING

Laser cladding by blowing powder into a laser generated melt pool is f inding greater use in industry particularly with the growing interest in direct build and repair techniques currently being investigated. Th e process is traditionally done with a side blown powder feed. This ha s the limitation of not being omnidirectional. To overcome this, a coa xial powder feed system has been developed. This article describes a p articular system by both mathematical models and experiment. The syste m has so far achieved a catchment efficiency of up to 40% with a 1 kW CO2 laser beam. The parameters controlling this important commercial p arameter are described. They include the flow structure of the powder in the beam. The control of this structure is discussed with reference to this particular coaxial flow system. (C) 1998 Laser Institute of A merica. [S1042-346X(98)00402-1].