Analysis And Suppression Of Top Bumps On Inner Surface Of Tubular Aluminum Alloy Parts During Selective Laser Melting (SLM

The research objective of this paper is a motor shell that enterprise undertaked in the aviation field.Since there are many cooling water channels inside the motor shell,it was required to have better cooling performance.During the additive manufacturing process,the placement of this cooling channel cannot be changed,and the support cannot be added,resulting in overhanging surface processing.Many convex particle defects will be generated on the top of the inner surface of the cooling channel,which will affect the cooling channel heat dissipation performance.And in the SLM processing of other parts,there may also be many cooling water channels.These cooling water channels will also produce convex particle defects after processing,which will greatly affect the performance of the parts.The convex particle defects at the top of the inner surface are analyzed and suppressed.The main research work in this paper is as follows:(1)Referring to domestic and foreign scholars to study the causes and treatment methods of convex particle defects in overhang structures,the macroscopic causes of convex particle defects on the inner surface of SLM overhang structures are analyzed,and the overhang surface convex particles are analyzed from the microscopic analysis of alloy powder sintering behavior and molten pool behavior.mechanism of particle production.(2)To comprehensively improve the forming quality of the cooling channel,analyze the defects that will occur when the parts are formed with overhanging structural features,and provide guidance for the subsequent optimization of the overall performance of the cooling channel.At the same time,a preliminary optimization of the convex particle defects on the top of the inner surface of the cooling channel is proposed for SLM forming.method.(3)Observed the distribution of convex particle defects on the top of the inner surface of the cooling water channel,and perform partition processing on the top convex particle defects on the inner surface of the cooling water channel.At the same time,the first experiment was designed according to the preliminary optimization method of convex particle defects on the top of the inner surface of the cooling channel formed by SLM,which mainly analyzed the effects of variable and non-variable overhang angles,6different scanning strategies,and the number of laser profile remelting on the molding quality of the inner surface of the cooling channel.Influence,and for the first time,the influence of 6 process variables(overall laser power,overall scanning speed,contour remelting laser power,contour remelting scanning speed,top laser power,and top scanning speed)on the comprehensive molding quality of cooling water channel is analyzed by range analysis magnitude and impact trend.(4)According to the results and analysis of the first experiment,in the second experiment,the scanning strategy,the number of contour remelting,and the range of six process variables were improved.At the same time,univariate analysis was carried out for6 process variables,and the trend of the comprehensive molding quality of cooling water channel changing with these variables was analyzed under the condition of other variables being fixed.(5)To meet the requirements of the factory and find the optimal process for the experimental cooling water channel,a GA-ELM-GA algorithm is proposed to optimize the cooling water channel forming process globally.Provide a reference for follow-up staff optimization.