Development of Multichannel Gas-powder Feeding System Coaxial with Laser Beam

摘要

Laser cladding is considered nowadays as a key technology of additive manufacturing in production engineering. Properties of gas-powder mixture (gas type, feeding rate, etc.), relative positioning of workpiece, laser beam focal spot and tilting angle of gas-powder stream symmetry axis significantly influence the results of laser processing. Development of an efficient system for the delivery of gas-powder mixture into the processing zone is crucial for the increase in the performance of laser-based additive manufacturing. Multi-channel nozzles for gas-powder mixture delivery into the processing zone is one of the most promising tools to achieve this goal. Different powder types could be introduced into the processing zone simultaneously and the required powder distribution and concentration could be reached. Results of numerical simulation of gas-powder stream behavior were used to design the original configurations of multi-channel nozzles that were manufactured and tested experimentally. Optimal technological parameters for the use of multi-channel nozzles in laser cladding were established. The observation of multichannel gas-powder stream formation at different working conditions has demonstrated good correspondence between the results of trial cladding and those predicted numerically. Cladded layers had a high level of uniformity since it was possible to control the powder distribution and concentration within the laser processing zone.