When working with ceramic-filled powders or other high-viscosity materials in additive manufacturing, small details make a massive difference, especially escape hole sizing. As the Scojet graphic emphasizes, “Small openings can cause big failures.” This is not an exaggeration. Inadequate escape holes prevent proper depowdering, which can sabotage the integrity and functionality of the part altogether.
Ceramic powders don’t flow like standard metal powders. Their larger particle sizes and higher viscosity make it harder for them to exit internal channels unless the escape paths are appropriately designed. The minimum recommended size for escape holes in such scenarios is 3–4 mm, which is significantly larger than for traditional metal AM. Ignoring this threshold leads to trapped material, internal clogging, and in some cases, catastrophic failure of moving or fluid-carrying parts.
The problems aren’t just functional, they’re systemic. Trapped powder adds unnecessary mass, creates stress concentrators, and blocks inspection tools like borescopes. Over time, this can result in warranty issues or performance degradation in the field. Worse yet, if the trapped material sinters slightly during the build, it can fuse with internal surfaces and become nearly impossible to remove during post-processing.
Furthermore, sharp internal corners tend to collect powder like dust in a vacuum. Rounding internal transitions and designing escape paths with smooth curvature can significantly enhance powder evacuation. This is why designing for ceramic AM requires a tailored mindset, what works for Inconel or Ti64 won’t necessarily work for ceramic-filled blends.
Ultimately, successful printing with ceramic powders isn’t just about material properties, it’s about designing with those properties in mind. Escape holes may seem like a minor feature, but in practice, they’re a major factor in build success.