Study On The Device And Formability Of Layered Extrusion Molding Ceramic Core

With the rapid development of the aerospace industry,the demand for complex interior structures,high quality and high precision aloy castings is increasing.The ceramic core used to form the cavity of the casting becomes very complicated,and the preparation is difficult and the cycle is long.Therefore,the rapid prototyping of complex ceramic cores has become a hot research topic.However,there are shortcomings in the existing processes and equipment,such as high cost,high raw material performance requirements and poor quality of parts,and there is currently no equipment for the rapid prototyping of ceramic cores and low cost materials.Therefore,this paper has carried out the research on the layered extrusion technology of ceramic core,studied the forming quality and sintering properties of the blanks which can be used for layered extruded ceramic core and the layered extruded ceramic core.Important theoretical and practical significance.In this paper,the melt deposition molding equipment has been modified to realize the rapid extrusion of ceramic core extrusion.The modification scheme is as follows: the wire feeding mechanism of the molten deposition molding equipment is changed to the slurry conveying mechanism,the double nozzle extrusion method is changed to the time pressure type cylinder extrusion method;the rapid extrusion of the ceramic slurry is controlled by the dispenser The original control system of the melt deposition molding equipment realizes the movement of the slurry extrusion head and establishes the fluid extrusion movement model.The rapid extrusion test of the ceramic slurry was carried out by using the layered extruded ceramic core device.The process parameters of the slurry extrusion were optimized.The results show that the layered extrusion molding device can produce triangular,circular and square shaped ceramic parts with better surface quality.The optimized parameters are as follows: the moving speed of the extruder is 20 mm / s,the needle and the substrate Of the distance of 2mm,the needle diameter of 0.84 mm,needle length of 3mm.The effects of different sintering temperature on the properties of ceramic core were studied by using the optimized extrusion rapid prototyping parameters.The results show that the porosity of the ceramic core decreases with the increase of the sintering temperature from 1400°C to 1600°C,the flexural strength,shrinkage rate,mass loss rate and bulk density of the ceramic core.When the sintering temperature is 1500°C,the comprehens ive performance of the core is the best,the flexural strength is 33.949 MPa,the length shrinkage is 4.88%,the mass burn rate is 2.18%,the bulk density is 2.14 g / cm3,the apparent porosity is was 33.1%.