A preparation method of ceramic core based on slurry direct writing molding

Abstract

The invention discloses a method for preparing a ceramic core based on slurry direct writing. First, a high solid content ceramic slurry and an organic slurry are prepared; then the prepared ceramic colloidal slurry and the organic slurry are injected into a double nozzle. In the two barrels of the direct writing equipment, the ceramic cores and supports are printed layer by layer according to the model data, and after each layer is printed, the nozzles equipped with the direct writing equipment are used to spray cold air to achieve rapid freezing of the printed structure. , and finally complete the processing of the ceramic core green body and the support; freeze-dry the ceramic green body to remove the moisture in the green body; put the dried green body into the roasting furnace for degreasing and sintering treatment, and finally obtain the ceramic core part. The ceramic core obtained by the preparation method of the present invention has suitable mechanical properties and high dimensional accuracy, and can meet the preparation requirements of the superalloy hollow blade.

Description

technical field [0001] The invention belongs to the technical field of investment casting, and relates to a method for preparing a ceramic core based on slurry direct-writing molding. Background technique [0002] Hollow turbine blades are the core hot-end parts of aero-engines and gas turbines. Its structure is complex, the process is difficult to realize, and the processing level is high, which has a decisive impact on the performance of the whole machine. Its manufacturing technology is a key technical bottleneck restricting the development of aero-engines and gas turbines. one. In order to meet the ever-increasing cooling requirements of turbine blades, complex cooling passages are designed inside the turbine blades. There are many cooling holes of various shapes on the surface of the blades, and the cooling structure is becoming more and more complex. All these need to be realized with the help of ceramic cores. Therefore, ceramic The core becomes one of the necessary ...

AI Technical Summary

Problems solved by technology

Due to the long design and processing cycle of the mold, there are problems of high manufacturing cost and long cycle time when using hot die casting and injection molding processes to manufacture ceramic cores

[0003] As a manufacturing technology with industrial revolution significance, 3D printing technology has been included in the national strategic emerging industry development plan. This technology constructs objects through additive manufacturing, especially suitable for the processing of complex structural objects. Currently, it is used in resin, Breakthroughs have been made in the commercialization of metal forming, but ceramic 3D printing technology is still largely uncommercialized

At present, the main problem is that when forming parts with unsupported long-span structures, the rheological characteristics of the ceramic slurry lead to collapse, and the size of the line extruded from the nozzle is affected by the movement speed of the platform and the extrusion pressure. Affected by many factors, such as, the dimensional accuracy and surface accuracy of the molded parts are low

The published patent of Xi'an Jiaotong University - a method for preparing ceramic molds for directional solidification of complex structural parts (application number: 201711376350.8), proposes to use dual-nozzle FDM printing equipment to use ceramic molds, and one nozzle to print ceramic mold parts , one nozzle prints paraffin support, but both need to be heated during the printing process. During the simultaneous printing process, it will cause local dehydration and deformation of the ceramic body, which will affect the forming accuracy and quality of the mold.

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