Study On Mechanism And Optimization Control Of Molten Deposition Molding

Fused Deposition Modeling(FDM)is one of the more widely used technologies in 3D printing additive manufacturing.Because of its simple equipment structure,many kinds of materials,and low manufacturing cost,its application fields are becoming more and more extensive.However,due to the limitations of technology and equipment,compared with traditional processing and manufacturing technology,the accuracy of FDM molding parts is generally not high,and the molding accuracy is also a key factor restricting its rapid development and application.This paper studies the problem of poor molding quality caused by the unbalanced temperature between layers in the FDM-3D molding process,and proposes an optimal solution.Based on the theory of heat conduction,the 3D transient mathematical model of fused deposition materials in the 3D molding process was established by using the principles of thermo-solid coupling,thermo-mechanical coupling and liquid-solid coupling.The FDM molding was realized on the ANSYS platform by using the life-death element technology and indirect coupling analysis.The visual simulation of the process analyzes the temperature field and stress-strain field in the material forming process,and obtains the temperature gradient distribution and the stress-strain variation law.The conclusion is verified by printing experiments.Aiming at the problem that the uneven temperature distribution between layers in the fused deposition molding process affects the molding accuracy,a layer variation model of the melting process is established.On the basis of theoretical calculations and simulation experiments,a 3D printing with an interlayer preheating structure is completed.The design of the device uses laser to preheat and control the temperature of the pre-printed interlayer area,which optimizes the interlayer temperature distribution during the printing process,improves the bonding strength of materials,and then improves the quality of the printed parts.In order to solve the problem that it is difficult to optimize the mutual coupling of process parameters in the FDM molding process,the influence of the three main parameters of printing temperature,layer thickness and scanning speed on the accuracy in the molding process was simulated and analyzed,and the coupling law between the influencing parameters was obtained.The global optimization of the control parameters is accomplished using the RSM-GA method.The test experiment of the improved device and the optimal parameter combination was completed.The results show that the designed preheating structure and parameter optimization method can effectively improve the precision and mechanical properties of the formed parts.