Research status of rapid investment casting

In the process of rapid investment casting, due to the different rapid prototyping process, the corresponding casting process scheme is different. Therefore, many scholars have carried out research on different rapid prototyping processes. Ferreira et al. Directly manufactured the casting core box by SLA and SLS rapid prototyping process, studied and compared the tensile modulus, tensile strength and other indicators of the core box with different processes, and determined the process route of preparing the core box. Marwah carried out multi jet modeling and melt deposition modeling for acrylate and acrylonitrile butadiene styrene based materials, aiming at the crack of ceramic shell in rapid investment casting process, and the influence of step effect and volume shrinkage of wax pattern prototype. The application of multi nozzle can greatly shorten the production time of specimens Olefins were decomposed at 500 ℃ and above 600 ℃ respectively. In view of the poor finish of FDM, Vivek et al. Found that the printed parts can meet the requirements of rapid investment mold after pretreatment, steam smoothing, chemical treatment and sandpaper polishing. Xu W L was fabricated by SLA technology, and the ceramic shell was prepared by gel casting technology. Alumina based ceramic mold with high temperature mechanical properties and dimensional stability was prepared by adding kyanite in alumina. Shi Yusheng and others used SLS sinter PS powder to prepare SLS prototype. Through the analysis of post-treatment of wax impregnation, the shell preparation process and demoulding process were studied, and finally the qualified ceramic shell was obtained. Shen Qiwen and others studied the process support software and scanning heating technology of super large SLS equipment, and analyzed the sintering characteristics of coated sand and PS materials. Xiong Xu [34] analyzed the dimensional accuracy of SLS prototype and wax mold melt loss in the rapid prototyping process of specimen, and studied the dimensional transfer law of specimen rapid prototyping. Liu Yaxiong et al. Prepared human bone tissue by light curing rapid prototyping, and reverse modeling of the casting after rapid casting, compared the model with the original model, and then determined the size shrinkage of different parts, and established the precision compensation mechanism of the part. Zhang Liangliang pointed out that in the process of ric technology, it is often necessary to optimize the structure of parts. A CAD / CAE / CACE integrated topology optimization method was proposed, and the topology design and analysis of ric lattice were carried out. Finally, the method was applied to the simulation analysis of investment casting of RIC parts. Wang Yongming used FDM rapid prototyping technology to prepare blade parts. Through the analysis of material expansion coefficient, a kind of internal collapse structure was designed, which made the wax mold collapse from the inside in the process of wax mold melting, thus solving the problem of shell bursting of this kind of parts. Wu Xiaoyong used ANSYS to simulate the PS selective laser sintering process, and analyzed and compared the process parameters of wax impregnation and resin impregnation, and obtained the best post-treatment process parameters.

To sum up, many scholars through the SLS A series of researches have been carried out on the preparation of forming materials, optimization of process parameters, control of dimensional accuracy, performance of forming parts, numerical simulation and so on. For rapid casting, different rapid prototyping processes and their corresponding investment casting methods have been studied. At the same time, the specific rapid casting processes under different rapid prototyping have been studied There is no report on the transmission law of medium size error and the size compensation of corresponding complex parts. In the face of the difference of precision of different molding equipment in molding parts, and the characteristics of complex and large-scale parts structure, in order to shorten the processing cycle of rapid casting parts. In the process of investment casting based on SLS for complex parts, it is necessary to study the transmission law of dimensional error and the compensation of dimensional error.