Defects control of manufacturing ceramic mold of hollow turbine blade based on stereo lithography

The cceramic mold is crucial for manufacturing hollow turbine blade. Obvious advantages of manufacturing integral ceramic mold based on stereo lithography (SL) are short cycle, low cost and rapid responding compared with investment casting, but how to control the fabrication defects of ceramic mold is a technological challenge for its development. The solution method for the step effect of SL prototype is researched, the gel-casting behavior of tiny structure in vacuum is discussed, and the influence of thermal stress is analyzed in the degreasing process. Result shows that the step effect of SL prototype is solved based on the principle of flowing property of liquid wax, and its surface roughness is remarkably improved; with the temperature increasing, the single-layer thickness of coating RP60 wax decreases, reaching a minimum of 0.06 mm at 90℃; with the solid content of ceramic slurry being less than 62%, acceptable filling result of tiny structure (0.5 mm) gel casting in vacuum can be realized. By hollowing out the SL prototype, the integral ceramic mold is fabricated with high accuracy and defect-free after degreasing.