Key Takeaways & Executive Findings
- •• Printing angle critically influences surface accuracy, shrinkage, and printing efficiency of green bodies, as well as microstructure and mechanical properties of sintered silica ceramic cores. • Increasing printing angle reduces bonding area, worsens surface roughness, increases Z-direction shrinkage, and decreases printing efficiency, while also lowering bending strength. • A printing angle of 30° halves printing time compared to 90°, improving molding efficiency while achieving required bulk density, open porosity, and flexural strength. • Optimizing printing angles enables a balance between shrinkage, printing efficiency, and flexural strength, offering a promising route for rapid manufacturing of complex ceramic cores.
Abstract
Ceramic cores fabricated by stereolithography exhibit great potential in casting turbine blades. Previous research on ceramic core molding was primarily conducted using vertical printing techniques, which not only resulted in lengthy molding durations but also compromised the mechanical strength. In this work, silica (SiO2) ceramic cores, with fine complex geometric shapes, were fabricated using 65vol.% ceramic slurry by digital light processing (DLP) with different printing angles. Printing angles significantly impact the surface accuracy, shrinkage, printing efficiency of green bodies, as well as the microstructure and mechanical properties of sintered ceramic core samples. As the printing angle in the green body increases, the bonding area decreases, surface roughness on the XY plane worsens, shrinkage in the Z direction becomes more pronounced, and the printing efficiency declines. Similarly, an increase in the printing angle in the sintered body leads to a reduction in bending strength. At a printing angle of 30°, the printing time is reduced to half of that at 90°, which improves the molding efficiency. Meanwhile, the obtained bulk density of 1.71 g·cm-3, open porosity of 24%, and flexural strength of 10.6±1 MPa can meet the requirements of sintered ceramic cores. Therefore, designing and optimizing the printing angles can achieve the balance between shrinkage, printing efficiency, and flexural strength.
1. Introduction
With the development of modern industrial manufacturing technology and the improvement of aero-engine performance [1], the products are increasingly required to be more precise and complex. Single crystal superalloy hollow blades with complex cavity cooling structures are increasingly urgent [2, 3]. As an important part of hollow precision and complex casting, the ceramic core has become one of the core elements in modern industrial manufacturing technology [4-6]. Ceramic cores are generally molded by injection molding [7, 8]. However, when producing ceramic cores with complex structures, hot injection molding technology faces the challenges of complicated processes, long production cycles, and high costs [9, 10]. In addition, limited by traditional molding methods, ceramic cores have approached the upper limit of achievable geometric complexity, making it increasingly difficult to fabricate components with complex structures [11, 12].
Stereolithography 3D printing ceramic technology is widely used to compensate for the limitations of traditional thermal injection processes in the preparation of complex core materials [13, 14]. Given the unique capabilities of 3D printing, industrial and academic interests in 3D printing complex shaped castings such as ceramic cores are booming [15-17]. The printing technology provides a feasible technique for preparing ceramic cores with complex structures [7, 18] due to its many advantages including high design flexibility, customizability, mold free manufacturing [19], reduced material waste, shorter production cycles [20], ability to control porosity, and improved mechanical properties [21, 22]. Therefore, ceramic cores with high performance [23], high precision [24], high bending strength [25], and reduced production cost can be manufactured through stereolithography technology. This approach offers a promising route for the rapid manufacturing of high-complexity, high-quality ceramic cores essential for producing hollow turbine blades [26].
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Yue Gu, Wen-yan Duan, Gong Wang, Bing-shan Liu, Xiao-dong Liu, Shan Li (2025). Effect of 3D printing angle on microstructure and mechanical properties of silica ceramic cores by stereolithography. China Foundry. https://doi.org/10.1007/s41230-025-4072-7
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Frequently Asked Questions
What is the effect of printing angle on silica ceramic cores?
The printing angle significantly impacts surface accuracy, shrinkage, printing efficiency, and mechanical properties. Increasing the angle reduces bonding area, worsens surface roughness, increases Z-direction shrinkage, and decreases printing efficiency and bending strength.
What printing angle is optimal for silica ceramic cores?
A printing angle of 30° is optimal as it halves printing time compared to 90° while achieving required bulk density, open porosity, and flexural strength, balancing efficiency and properties.
What are the mechanical properties of the sintered ceramic cores?
At a printing angle of 30°, the sintered cores exhibit a bulk density of 1.71 g·cm-3, open porosity of 24%, and flexural strength of 10.6±1 MPa, meeting requirements.
Why is stereolithography used for ceramic cores?
Stereolithography offers high design flexibility, customizability, mold-free manufacturing, reduced waste, shorter production cycles, and improved mechanical properties, enabling fabrication of complex ceramic cores for hollow turbine blades.
What is the significance of this research?
This research demonstrates that optimizing printing angles can achieve a balance between shrinkage, printing efficiency, and flexural strength, providing a promising route for rapid manufacturing of high-complexity ceramic cores.
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