Research On Powder Feeding System In Titanium Alloy Laser Rapid Repair And Process Experiment

Laser rapid repair technology is an advanced manufacturetechnology that based on laser cladding and laser rapid formingtechnology, with the unique advantages of controllable energy, nomold, near net forming and high degree of flexible, which offersa new way to the repairment of complex and expensive parts. It utilizemolten pool that is formed by the laser irradiation to combinecladding material and undone repair substrate, in the process,whether the powder feeding system can be accurate、uniform and smoothdeliver the powder granules into molten pool has great influence onrepair effect.Powder feeding system is mainly composed of coaxial powderfeeding nozzle and powder feeding device. The FLUENT software is usedto simulate powder flow field based on the gas-solid two-phase flowtheory, and the key parameters of powder feeding nozzle weredetermined based on the simulation results. To ensure the workingstability and continuity,a double-layer cooling structure and fourhole powder feeding channel mode was used for its near to molten pooland laser beam. Then synchronous powder feeding device was designed,which can achieve the precise powder through controlling the powder disc speed, and the shading protective device was added to ensurethe normal operation of auxiliary equipment.In order to verify the powder feeding system reliability andvalidity, the experiment about powder gathering、the efficiency ofusing powder and surface quality and repair forming were done. Powdergathering experiment validates the actual convergence effect ofpowder feeding nozzle; The powder using efficiency experimentexplores effect of different technological parameter on theutilization ratio of the powder, such as power, scanning direction,scanning speed and so on, which provide a basis to optimize processparameters. Surface quality experiment is an explorative experimentwhich connects powder feeding system with laser equipment andresearchs the impact of different technological parameter on surfacequality of repair parts. Repair and forming experiment is the actualrepair experiment based on the optimization of process parameters,which verifys the performance of powder feeding nozzle and powderfeeding device from the actual repair effect.