Research On Decomposed Injection Sculpturing Process Of Metal Parts

Decomposed Injection Sculpturing(DIS) is a novel technology by theintegration of traditional CNC machining and discrete/additive process, it hasthe accuracy of traditional machining process as well as the flexibility ofdiscrete/additive, whereas there are many issues such as the poor interfacialadhesion between segments. Mold Decomposed Injection Sculpturing is thecombination of gelcasting and DIS technology. The process has excellentfeatures, in which the problems occuring in interfacial layer can be ignored.The further study on mold DIS process focus on the following aspects: thematerial system, method of drying, debinding and sintering, instancevalidation.(1) Material system: The new material system is studied by using thegelatin as cementing agent, the sodium alginate as dispersing agent and the316L stainless steel powder as raw material. The characteristics of thecementing agent, the pH value of the solution, rheological property of theslurry and performance of the green body are under investigation. The slurrywith high solid content and low viscosity less than1000mPa·s is prepared atlast, and the bending strength of the green body has been further improved.(2) Method of drying: The drying method of vacuum freeze is comparedwith ordinary drying method in the following three aspects: formed quality,linear shrinkage and bending strength. The result is that: Through the dryingmethod of vacuum freeze, the phenomenon of obvious shrinkage and crackingis not appeared, the linear shrinkage is low, the green body is almost keptunchanged in shape and dimension, and its bending strength has been greatlyimproved. So advantages by using the drying method of vacuum freeze areverified.(3) Degreasing and sintering: The reasonable degreasing process isdeveloped by the analysis of DSC and TG. The impact of the sintered body performance on the sintering temperature, sintering time and heating rate isstudied by orthogonal experiment method, and the optimized combination ofthe processing parameters is determined through the range analysis, varianceanalysis and the consolidated balance analysis.(4) Instance validation: A compression turbine of the aircraft engine ischosen as the instance of thin-walled metal functional part, It is finishedthrough the combination of gelcasting and mold Decomposed InjectionSculpturing technologoes. The sample part exhibits good surface quality, nocracking, no warping in appearance, and good dynamic balance at the speed of8000r/min is achieved.Works have been done to further improve the mold Decomposed InjectionSculpturing in the aspects of the material system, drying method, debindingand sintering processes. The feasibility of this process is verfied through aprctical part sample produced by this technology at last.