The Laser Cladding Of Variable Cross-section Thin-walled Part Based On Coaxial Inside-Beam Powder Feeding

At present, the powder feeding way of LCRM are lateral powder feeding and coaxialpowder feeding outside the laser beam. Under the first kind of way, laser beam and powdercouples badly, and the accumulated parts have rough surfaces. Under the other kind of way,the structure is relatively complex and hard to control. And the common disadvantage ofthe two ways is the low utilization of metal powder. Soochow university laser specialprocessing lab put forward a new laser cladding manufacturing process with coaxialinside-beam powder feeding. It can make the laser beam and the powder couple well andimprove the utilization rate of powder. And it has a relatively uniform molten pool energydistribution. It also can make the cladding layer more flat. This article focuses onresearching and analyzing the energy distribution and changes of the temperature field inthe new technology; Analyzing the laser cladding forming process under the existingtechnical conditions. And in this paper, the temperature field of the circular cross-section tooval cross-section gradually changes thin-walled part and it’s forming technology will beresearched.Through the analysis of light and powder coupling theory, this paper has designed aregulatory mechanism for the powder feeding nozzle adjustment base on coaxialinside-beam powder feeding laser head. It can be used to adjust the powder feeding nozzlebefore the experiment and during experiments. Experimental results show that theimproved laser head can ensure good light and powder coupling; it can improve thepowder utilization and be useful for the variable cross-section thin-walled parts lasercladding forming.This paper systematically studied the effects of laser power, powder feeding rate andscanning speed to single cladding layer’s surface, height, width and the aspect ratio. Thispaper has established a regression equation between the aspect ratio and the aboveinfluence factors, and it passed the test of significance. All of these provide an importantreference for the laser cladding forming of variable cross-section thin-walled part based on coaxial inside-beam powder feeding.The energy distribution under annular laser irradiation was analyzed. This article usedthe software of ANSYS to create a finite element model of the single-channel claddingunder the same conditions. The temperature contour maps of different location points showthat the temperature distribution under the annular laser irradiation is more uniform thanthe traditional laser irradiation. And it shows that the annular laser cladding has moreadvantages in the aspect of forming.In the PMAC control system platform, the laser cladding forming process of variablecross-section thin-walled part has been compiled. Base on the single laser claddingexperiments, the laser cladding forming initial parameters and test plans of variablecross-section thin-walled part are confirmed. The finite element model of laser claddingforming variable cross-section thin-walled part is established. The thermal cycle of thenode are studied during the variable cross-section thin-walled part forming process. Thevariable cross-section thin-walled part is formed successfully through storey height controlof CCD and laser power change real time as the simulation results of ANSYS. Bysubsequent heat treatment of the formed part and analyzing its surface morphology,dimensional accuracy, microstructure, micro-hardness and wear-coefficient, it can beconcluded that the formed part has smooth surface, no powder paste outside the surface,the size is basically the same to the design value, the microstructure is small and density,metallurgical combination is formed between part and substrate.