Research On Surface Forming Accuracy Control Of Laser Deposition Manufacturing

The surface forming accuracy of laser deposition manufacturing is related to many factors,not only related to the main process parameters,but also affected by the heat distribution of the parts during the forming process.In addition,the phenomenon of the concave and the edge collapse on the surface of the parts will occur in the forming process,which will affect the surface forming accuracy of the parts.Reasonable selection of process parameters is the basis to ensure the surface forming accuracy.Studying the heat distribution law and the mechanism of surface the concave and the edge collapse can establish the theoretical basis for optimizing the forming process,and then can play the role of surface forming accuracy control.In this regard,the following research work has been done in this paper:Firstly,the PSO algorithm combined with BP neural network is used to establish the prediction model of the morphology of the deposited layer by laser deposition manufacturing.The multi-channel single-layer experiment is completed,and the collected data is trained and verified by network.The verification results show that the prediction model has higher prediction accuracy and can facilitate the screening of process parameters.Then,the finite element model of the T-beam is established.The temperature field simulation is carried out on the T-beams formed by different scanning strategies.The laser deposition experiment is completed.The temperature field model is verified by the infrared camera,and the CCD camera is used.Combined with the special image processing software,the width of the molten pool at the part level was collected,and the influence of different scanning strategies on the heat distribution and surface forming quality of the T-beam was analyzed.The analysis results show that the heterogeneous scanning,variable pitch scanning and layered cooling scanning strategies can improve the heat distribution at the part level and improve the surface forming quality of the parts.Finally,the combination of theoretical analysis and experiment is used to study the phenomenon of the concave and the edge collapse on the surface of rectangular block,and the solution is given.The research results show that with the increase of the number of layers in the process of laser deposition manufacturing,the actual defocusing amount of the workpiece will become larger,and the phenomenon of concave and sag on the surface of the workpiece will be aggravated,which seriously affects the surface forming precision.