Development of powder delivery nozzles for laser gas-powder cladding

Abstract

Along with processing parameters, material properties of the workpiece and the powder, the quality of focusing of gas-powder stream is the key parameter that can influence the productivity, quality and costs of laser gas-powder cladding, rapid prototyping by selective laser sintering and surface modifications. Unfortunately, there is almost no information on the methodology for the design of gas-powder streams delivery and simple methods for the control and measurement of gas-powder stream characteristics.Development of the methodology for the design gas-powder streams delivery nozzles that are used in laser gas-powder cladding and simple methods for the control of gas-powder stream characteristics.Numerical methods of vector optics, gas dynamics and image analysis were used.Original systems for the implementation of laser gas-powder cladding with increased productivity and low rate of powder waste were designed, manufactured and verified experimentally.It was established that the use of multi-channel nozzles for the delivery of gas-powder stream into laser beam processing zone increase the productivity of technological processes of laser cladding (especially for the cases when workpiece is not positioned perpendicularly to the laser beam) if compared with traditional coaxial and one-channel nozzle. Another benefit of multi-channel nozzles is that it is possible to introduce simultaneously two or more different powder mixtures into the processing zone.