Study On Manufacturing Process Of The Shell Applied To Near Net Shape Casting Method Of Layered

Layered casting near net shape manufacturing technology is a new type of discrete accumulation forming ideas on RP technology. This method is through the online production of layered shell to support and bind the metal liquid. The layered casting is completed by plasma deposition and it can be used to manufacture high performance complex structure of metal mold directly. Layered casting near net shape manufacturing technology can be used to manufacture precision, complex, and thin-wall nonferrous metal parts to overcome the plasma deposition modeling in large inclined angle parts of liquid metal flowing problem.The curing mechanism of Phosphate binder had introduced in this paper. The factors was studied on influencing shell slurry curing time, mobility, strength, gas evolution and the control parameters. It was studied on the shell manufacturing technology based on rapid prototyping technology. The layered shell is an important part of the technology, and the paper is based on the shell and the shell technology of the layered casting process is studied.The main results are:(1) The performance requirements of the shell was analysed,the refractory and bin der were optimized.The stirring process parameters of shell slurry were studied simultan eously.(2) The influence of the shell quality made by different forming parameters was studied in detail, the result shows that the shell quality goes worse with the increase of curing temperature, the density of adhesive, and goes better with the increase of ratio of liquid to powder, refractory material granularity. The addition of citric acid has a certain improving effect on shell quality, but excessive amount would be counterproductive. The best parameters: The curing temperature is 200℃ ~300 ℃, the density of binder is 1.50g/cm3, the ratio of liquid to powder is 0.44, refractory material particle size is 325 mesh, citric acid is added 2%.(3) When the multilayer shell was deposited, the lateral wall was flowing,which two of them were over packing, when the deposition width is 10 mm and thickness is 3mm, it is possible that this phenomenon can be alleviated. At the same time, when the slurry was deposited, the cantilever measurement factor is that the maximum of the hanging wall inclination angle is 30, and the wall offset is 1.7mm.