Research On Laser Cladding Rapid Manufacturing With Coaxial Inside-Beam Wire Feeding

Laser cladding rapid manufacturing (LCRM) is a novel manufacturing techniqueused to fabricate fully dense components. Feeding powder laser cladding process isquite mature in the field, but which powder utilization rate is low compared with thefeeding wire laser cladding process(outside laser coaxial-powder feeding utilization:20%-30%, internal laser coaxial-powder feeding utilization:50%-80%, laser wirefeeding utilization:100%). Aiming at the disadvantages of lateral wire feeding, anew inside-laser coaxial wire feeding process is adopted that can ensure a goodaxiality between wire and laser beam through transmitting wire along the centerlineof the laser beam.Base on the process of LCRM with coaxial inside-beam wire feeding, a morefacilitate adjustment device has been designed, which realizes the coaxial coupling ofthe wire and the laser beam by adjustting the annular focus lens to move the focus’level position and improves the safety of operation.The novel device was applied in the comparison experiments of laser claddingwith with different process parameters. The influences on the surface quality ofcrucial process parameters were investigated, such as laser power, scanning speed,wire delivery rate, defocusing amount and so on. Experimental results show that theprecondition of forming continuous cladding is to choose a suitable negative defocusdistance and the influence of wire delivery rate on cladding layer section’s width andheight is remarkable and the interaction of each process parameter influences thecladding layer section’s size. The optimum process parameters are selected throughorthogonal test and directional scanning experiment proves laser cladding withcoaxial inside-beam wire feeding can effectively eliminate the problem of scanningdirection.Mathematical modal is built for the relationship between process parameters andcladding layer section’s width and height with regression equation and statistical testswere carried out to verify the model. Through analyzing factors main effect, it isshown that laser power is positive relation with cladding layer section’s aspect ratio and the effect of wire delivery tate on cladding layer section’s aspect ratio. Themathematical model conclusion is consistent with the experimental analyses whichproves theoretical analyses correct.Based on the optimal process, a fine multy-layer hollow rotary parts was formedby keeping the defocus distance unchanged and adjusting the laser power in time.There are no subsidence damage and crack on the whole cladding layer. The widthand the thickness were uniform and the microstructure was uniformly distributed.The hardness of the laser cladding was uniformly distributed and larger than thesubstrate.