Design Of Fluidized Bed Based Powder Feeder For Laser Remanufacturing And Feeding Process Reseach

Laser remanufacturing as a new repair process technology has been revealing a certain superiority in modern equipment manufacturing industry. To ensure the quality of remanufacturing, having stable and accurate feeding rate is essential for remanufacturing process. In order to satisfy small feeding rate and high precision of laser remanufacturing, a powder feeder based on the principle of fluidized bed was designed in this paper. Then created the model of this powder feeder and simulated it. At last, to control this feeder effectively, a closed loop control system was designed.According to the preliminary structure design of the powder feeder, this paper used Fluent (a kind of numerical simulation software) to analyze the unsteady state flow of powders. The results show the state of motion and the density distribution of powders that under different fluidizing gas flow. And the powders are all in a fluidization state, which is an ideal state for transmission. So with these results and improvements, the feasibility of the feeder was verified.Experiments employed75～109μm nickel-base alloy, conducted in dry indoor environment. The feeder was tested respectively under different structure size of powder feeder, different control method of pneumatic circuit, and different flow rate of fluidizing gas flow. According to the tests’results, the structure of feeding device and pneumatic circuit were improved. Then based on this improvement, the paper took the orthogonal experiment, and used artificial neural network to analyze the data. Researches show that with appropriate small inner dimensions, the minimum feeding rate of the feeding device can be1.7g/min; fluidizing gas flow influences the feeding rate significantly, it will increase when fluidizing gas flow becomes large, and they have a certain linear relationship; the top outlet gas flow has less influence on the feeding rate; and the powder conveying gas flow has minimal impact on the feeding rate. The feeding rate range of the optimized feeder is from2.5g/min to44g/min.Programmable logic controller (PLC), weight sensor and electrical proportional valve constitute the main components of the closed-loop control system. In order to achieve the control of feeding rate, PLC equipped with PID algorithm was applied. Meanwhile, signals which monitored by the weight sensor were converted, and with these converted signals the electric proportional valve can be controlled effectively.