Studies On Application Of 3D Printing Technologies In Investment Precision Casting Samples

Investment casting has the advantages of high dimensional precision and high surface finish,however,it has some limitations such as too many manufacturing processes and long process cycle.Especially during the new product development,the design drawings of the samples need to be revised repeatedly before they can be put into production that is the reason why it needs a long manufacturing cycle.In order to shorten the manufacturing cycle,considering that it is difficult to shorten the process time of shell making,the research team thinks that 3D printing technology is an effective method to replace the traditional wax pattern manufacturing process.Abroad the research in this field has accumulated many years of experience and gradually spread to commercial applications.Domestic research in this field is relatively later than foreign research,then in active production to promote.However,the lack of theoretical foundation limits the application of this technology in enterprises,so it is necessary to obtain more experience and innovation from the level of basic research,and then to promote its application in enterprise production.Based on the investment precision casting technology and the rapid manufacturing capability of 3D printing technology,this paper selected the fused deposition modeling(FDM)technology and the stereo lithography apparatus(SLA)technology through comparison and analysis.The method of manufacturing wax pattern in traditional investment precision casting was studied and improved.A new manufacturing method of wax pattern was put forward,and the manufacturing verification of Exhaust Gas Recirculation(EGR)joint and ring drawing die was completed.In this paper,the traditional investment precision casting technology was analyzed,and the 3D printing rapid prototyping technology was introduced.The method to shorten the production cycle of the investment precision casting by use of the existing 3D printing technology was mainly studied.This paper discussed the experimental scheme of 3D printing technology used in wax mould and mould manufacture: FDM technology was used to print wax pattern directly,and SLA technology was used to print core cavity part of mould to make wax pattern.This paper also analyzed how to select printing materials,printing equipment and printing methods to ensure the surface quality and dimensional accuracy of the printing model.In the experiment,chose EGR joint wax mould and printing ring die as examples,the manufacturing experiment was carried out in the production practice,and the precision of the final castings was tested.The results showed that the casting precision can reach the precision of sodium silicate casting.In the process of design and manufacture,a series of problems were explored,including the coating property and adhesive property of the printing wax pattern,how to successfully removed the wax pattern from the mold shell without breaking the mold shell.How to design the inlay structure of the printing die to ensure its matching precision,and how to solve the influence of the low heat transfer coefficient of the printing die,and so on.The rapid manufacturing wax pattern studied in this paper has great practical significance to shorten the investment casting cycle.The research of SLA molding technology based on FDM provides a good method for die manufacturing.It has the innovative design of applying 3D printing technology to the investment casting process and improves the production efficiency.This paper has successfully designed and manufactured the EGR joint parts and the ring drawing die which can be used in production,which provides reference for the development of the new technology of wax pattern production in the future.