Research On Dimensional Error Of Rapid Investment Casting

Rapid Investment Casting technology is a widely used manufacturing technology that combines Rapid Prototyping with traditional casting,and realizes the transition from rapid prototyping to rapid casting.For the high-precision casting and manufacturing of complex structural parts in aviation,aerospace,navigation and engine manufacturing industries,it overcomes the shortcomings of long development time of traditional casting molds and large capital investment in the early stage.However,because the rapid investment casting technology needs to go through parts printing,parts post-processing and alloy solidification and other steps,the transfer of dimensional errors in the forming process has a greater impact on the accuracy of castings.Therefore,this article uses the selective laser sintering(Selective Laser Sintering,SLS)method to make the mold and the casting,The research focused on the transfer rule of dimensional error between SLS prototype relative to CAD model,wax model relative to SLS prototype and casting relative wax model.The main research contents are as follows:Firstly,Analyze the source of dimensional error and the transmission path of dimensional error in the process of rapid investment casting,and the effect of the temperature and number of wax immersion on the dimensional error and surface quality of the SLS prototype in the wax post-treatment process.Simultaneously analyze the effect of different wax temperatures of primary dipping wax on the size error of SLS prototype,and the effect of the thickness of secondary wax coating wax layer on the surface quality of SLS prototype to determine the optimal wax dipping process parameters.Secondly,Use reverse engineering technology to perform point cloud data detection on wax models of typical complex parts,scan and compare using Geiomagic Control software to obtain the results of wax mold size comparison of typical complex parts,and calculate the theoretical size errors of wax models to achieve There is a verification of the dimensional error transfer law.Finally,by determining the error compensation method,combined with the dimensional error transfer rule and the machining allowance,the SLS prototype of typical complex parts is made.Finally,The SLS prototype of complex parts after the dimensional error verification is qualified to post-dip wax treatment,besides the casting system was designed.the ProCAST software was used to perform casting simulation and simulation to verify the rationality of the casting system and the casting process,through the combination of casting system,shell preparation,alloy casting,shelling treatment,cutting gate riser and other processes obtained corresponding castings,analyzed the defects of the castings,and improved the casting system,and finally completed the rapid investment casting of qualified complex parts,and verified the casting size error compensation.It is proposed that it has a certain reference value to production practice.