Study On Temperature Field Of Different Heat Source Models In Selective Laser Melting

Selective laser melting(SLM)is a new type of additive manufacturing technology.Its forming parts have good microstructure and properties,high dimensional accuracy and high surface quality,and little limited by the shape of the forming parts.In recent years,it has developed rapidly.Accurate simulation of temperature field in SLM forming process,it is the premise of optimizing the forming process parameters,and improving the forming efficiency and the performance of the forming parts.For a long time,different researchers choose different heat source models to study the temperature field of SLM forming,but the calculation results of different heat sources are quite different.In order to clarify the influence of different heat source models on the calculation results of temperature field,four kinds of common heat source models are used:Gaussian surface heat source model,Gaussian cylinder heat source model,Gaussian index-abate heat source model,Double ellipsoid heat source model.The temperature field of selective laser melting 18ni300 was calculated.And ANSYS APDL finite element analysis software is used.The calculation results of each heat source model were compared.The reason of the gap between the size of the molten pool calculated by the heat source model under different process parameters is analyzed.Finally,the reliability of the calculation results of each heat source model is compared through experiments.The results show that,the maximum temperature calculated by different heat source models decrease exponentially with the increase of scanning speed,and increases linearly with the increase of laser power.Because the energy distribution of different heat source models is different,the maximum temperatures calculated by different heat source models are quite different under the same conditions,the maximum temperature of molten pool calculated by Gaussian surface heat source model is higher than that calculated by other heat source models,the heat affected area is the smallest,but the temperature gradient is the largest.And the heat affected area calculated by Gaussian surface heat source model is greatly affected by the scanning speed,with the increase of scanning speed,the heat affected area becomes longer and narrower.About the molten pool size,with the increase of scanning speed,the width and depth of molten pool calculated by different heat source models decrease exponentially,and increases linearly with the increase of laser power.When the depth of molten pool is less than the powder thickness,the change of molten pool is small.At the same linear energy density,the molten pool increases with the increase of laser power and scanning speed.The width and depth of molten pool calculated by Gaussian cylinder heat source are larger than those calculated by Gaussian index-abate heat source and Double ellipsoid heat source.There are intersection points between the molten pool calculated by Gaussian surface heat source and calculated by volume heat source.And the scanning speed corresponding to the intersection point increases with the increase of laser power.The main reason for the difference of molten pool results calculated by different heat source models is that the different heat source models consider and ignore different factors.The experimental results show that,the changing trends of molten pool with scanning speed or laser power calculated by different heat sources is consistent with that of experimental molten pool.Due to the different factors considered and ignored by different heat source models,there are different degrees of differences between the molten pool calculated by different heat sources and the experimental results.But the results of molten pool calculated by Double ellipsoid heat source are in good agreement with the experimental results.