Study On Laser Metal Forming Process Of Rosin Alcoholl Adhesion And Powder Coating

For the current laser additive manufacturing process,the simultaneous powder feeding method has a low utilization rate and is extremely wasteful.It needs to consider the environmental pollution of the powder and powder recovery,and the powder adhesion method is difficult to control the powder coating thickness.In the laser forming process,The adhesive layer is easily peeled off,and the gasification and decomposition of the binder easily cause problems such as contamination of the forming layer.Firstly,a kind of metal powder slurry powder laser forming process was developed.According to the problems such as complicated process and long process time,the improvement was optimized.The rosin alcohol bonded powder coating laser metal forming process was developed.The effects of various process parameters on the quality of rosin alcohol-bonded and deposited laser metal forming layers were studied by using a metal powder powder laser forming experimental platform.The microstructures of the rosin alcohol-bonded powder laser metal forming parts and the synchronous powder feeding laser molded parts were observed and analyzed using an Olympus microscope,a bulk microscope,and a scanning electron microscope(SEM),and the Vickers microhardness tester was used.Rockwell hardness tester and electro-hydraulic servo dynamic and static universal testing machine test the hardness and tensile strength of the test piece.Experimental results show:(1)In the process of rosin alcohol sticking and powder coating,under certain other conditions,the faster the stepping motor rotates,the more powder is delivered per unit time,and the thicker the powder is,the more the three-dimensional motion platform feeds.Faster,thinner powder thickness;the thickness of the metal powder preset layer can be controlled by the speed of the stepper motor and the feed speed of the three-dimensional motion platform;under certain conditions,the rosin alcohol nozzle mouth is vertical to the substrate.The farther away from the straight line,the faster the jetting speed of the rosin alcohol solution,the deeper the ditch is formed by the jet impact.When the vertical distance from the nozzle of the rosin alcohol nozzle is less than 6 mm,during the paving process,the rosin alcohol solution meets the powder and easily makes the powder.Rapidly build-up of compacted clogging of the powder outlet,the jet rate of rosin alcohol solution is too small,some metal powder layer can not be formed with the rosin alcohol solution has a certain bond strength of the metal powder preset layer,comprehensive considerations,rosin alcohol nozzle mouth from the base The vertical distance of the material is 7~8.5mm,and the spraying speed of rosin alcohol solution is 4.24~6.37mm/s.(2)Under certain other conditions,with the increase of the concentration of rosin alcohol solution,the bond strength also increases.During the laser metal forming process of rosin alcohol bonded powder coating,the metal powder preset layer near the melting point The less prone to cracking,when the concentration of rosin alcohol solution reaches 1.8%,there is no crack in the pre-metal powder layer near the melting channel,and the laser metal forming layer of rosin alcohol-bonded powder is of good quality;under the same conditions,the laser power The higher the density,the slower the scanning speed and the wider the width of the melting path;the smaller the scanning distance,the higher the bridging rate of the melting path.When the bonding rate is 50%,the quality of the laser forming layer is good;other process parameters are the same.In a certain range,with the increase of the powder coating thickness,the tensile strength of the molded part is significantly reduced;the gas protection energy can reduce the oxidation burn of the alloy powder during the metal forming process of rosin alcohol-bonded powder coating to a certain degree.Improve the quality of molded parts.(3)As the binder rosin in the rosin alcohol bonding powder laser metal forming process is a hydrocarbon,in the laser forming process,the transient reducing protective atmosphere formed by the rosin gasification combustion reduces the metal molten pool Oxidation damage of the alloy powder and good slagging of the rosin reduce the generation of defects such as blowholes and slags,and improve the quality of the molded parts,thereby making the formed pieces of rosin alcohol-bonded and powdered laser metal forming process.The mechanical properties are superior to those of the molded parts produced by the synchronous powder-feed laser forming technology.