DLP Ceramic Core-Shell Mold for Fine Cooling Holes

The patent replaces conventional powder bed or selective laser sintering processes with direct light processing (DLP) technology. DLP uses a digital light processor to project UV light patterns that cure liquid photopolymer resin layer by layer, enabling much finer resolution (typically 25-50 micrometers) compared to laser sintering. This substitution allows production of fine filaments with diameters down to 0.5mm while maintaining automation, as the DLP system can rapidly cure entire layers simultaneously rather than scanning point-by-point with a laser.

The invention changes the fundamental processing parameters by using photopolymerization chemistry instead of thermal sintering. The DLP process uses UV light wavelength, exposure time, and resin formulation parameters to achieve fine feature resolution. By adjusting the photopolymer resin viscosity, crosslinking density, and light exposure parameters, the process can produce fine filaments that would be impossible with conventional laser-based methods, thereby resolving the contradiction between automation and manufacturing precision.

The patent merges the mold-making process with the cooling hole formation process by using DLP to directly print the ceramic mold with embedded fine filament structures that define the cooling passages. Instead of separately creating the mold and then drilling or forming cooling holes, the DLP process consolidates these steps into one additive manufacturing operation. The fine filaments are printed as integral parts of the mold structure, and when the mold is used for casting, these filaments define the cooling hole geometry directly, significantly reducing process complexity while maintaining reliability.

The invention performs preliminary action by pre-forming the cooling hole geometry within the mold structure itself during the DLP manufacturing process. The fine filaments are printed in advance as part of the mold, and their removal after casting leaves precisely formed cooling passages. This preliminary formation of cooling features eliminates the need for post-casting drilling or complex tooling, reducing both device complexity and manufacturing steps while preserving the reliability of established investment casting methods.

The patent applies local quality by using different material properties or structural characteristics in different regions of the mold. The DLP process can vary the exposure energy, layer thickness, or resin formulation locally to optimize filament strength where needed while maintaining fine dimensions. Additionally, the mold design can incorporate localized reinforcement elements or support structures in critical areas, while maintaining thin filament geometry in regions where fine cooling holes are required. This spatial variation of properties allows the mold to simultaneously achieve high resolution cooling holes and maintain overall structural integrity.

The invention uses composite materials, specifically photopolymer ceramic composites, that combine the benefits of fine feature resolution with enhanced mechanical properties. These composite resins contain ceramic particles dispersed in a photopolymer matrix, providing both the dimensional accuracy needed for fine filaments and the structural strength required for mold integrity. The ceramic content enhances heat resistance and mechanical strength, while the photopolymer matrix enables precise DLP fabrication of thin features, resolving the contradiction between resolution and strength.