基于光固化成型技术的空心叶片陶瓷铸型制造缺陷控制

陶瓷铸型是制造空心叶片的核心，相对于熔模铸造主流技术，基于光固化成型技术的一体化陶瓷铸型制造方法具有显著的优势：周期短、成本低、响应快，但如何控制铸型的缺陷是该方法发展的技术难题。为此，研究光固化原型台阶效应的解决方法，探讨铸型精细结构的凝胶注模复型行为，分析脱脂过程热应力对铸型质量的影响规律。结果表明：基于液态石蜡的流平性原理，可解决光固化树脂原型的台阶效应问题，显著减小原型表面粗糙度；随温度升高，覆膜RP60石蜡单层厚度减小，90 ℃时稳定在0.06 mm左右；当陶瓷浆料固相体积分数不大于62%时，可实现0.5 mm细小特征陶瓷铸型的凝胶注模真空无缺陷复型；通过镂空处理，脱脂陶瓷铸型无缺陷、精度较高。

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.