Research Of Single-road Cladding Process Based In Inside-beam Powder Feeding And Nozzle Optimization

Laser cladding rapid prototyping technology has become one of the importantresearch directions of advanced manufacturing technology. It is becoming more and moremature after years of development. And coaxial inside-beam powder feeding laser claddingforming technology owns a place in the field of laser cladding rapid prototypingtechnology with its unique energy input and powder delivery method. In this research field,the most basic and the most important research is controlling the morphology of claddingmelt channels. Based on coaxial inside-beam powder feeding, this paper has the researchon the morphology control of claddding melt channels from three aspects which areoptimization of the coaxial inside-beam powder feeding nozzle, establishment ofsingle-channel cladding process model and analysis of the influence of process parameterson the cladding layers’s interface morphology.During the study, this paper analyzed the effect of the nozzle structure on theaggregation of the shield gas by ANSYS Workbench12.0. Results can be showed asfollows. The aggregation of the shield gas becomes better with the enlargement of theshield gas’s velocity. The aggregation is the best when the angle of the shield gas’s annularoutlet is ten degrees. The aggregation is better when the ratio of the outlet’s inner and outerdiameters is1to2or1to3. The aggregation is better when the powder feeding pipe doesnot extend or protrudes1mm.This paper collected and analyzed the data of the cladding layers’s width and heightby Response Surface Methodology (RSM) and Minitab5.0. Then the process models ofthe laser cladding process parameters to the cladding layer’s morphology were established.This paper analyzed the influence of process parameters on the interface morphologyof the cladding layers. Results can be showed as follows. The gas-solid and solid-solidinterfaces of the cladding layers become smoother and flatter with the decrease of the laserpower. The gas-solid interface becomes higher and the solid-solid interface becomes deeper with the decrease of the scanning speed. The gas-solid interface becomes flatter andthe solid-solid interface does not change with the decrease of the powder feeding speed.The gas-solid interface becomes wider and the solid-solid interface becomes wider andshallower with the enlargement of the defocus amount. In addition, the peak of the laserpower transfer to the edge which leads to the solid-solid interface middle shallow and sidesdeep. The interface morphology of layers was controlled by changing process parameters.