Ceramic 3D printing has emerged as a groundbreaking innovation in advanced manufacturing. 
Traditional ceramic shaping methods, like injection molding and die casting, have trouble making complex shapes. However, 3D printing uses a layer-by-layer method that breaks these limits.
People value ceramics for their strength, heat resistance, and biocompatibility. Industries like aerospace and medical implants are eager to use this technology.

Original link: 3d printing of ceramics: a review
ADT official website

The growth of ceramic 3D printing comes from a strong need to create complex designs. These include porous lattices and overhangs that molds cannot make.
For decades, ceramic manufacturing relied on costly, time-consuming tooling. That changed in the 1990s when pioneering research papers sparked a wave of innovation.
Today, slurry-based technologies are at the forefront of high-precision ceramic 3D printing. They use light, inkjets, or extrusion to turn liquid ceramic mixtures into solid objects. Now, let’s unpack how five key slurry methods are reshaping what’s possible.

Slurry-Based Technologies: Where Liquid Magic Meets Precision

Slurry-based methods mix ceramic particles with light-sensitive resins or binders to create a liquid "ink." They then solidify this ink using light, inkjet droplets, or extrusion.

The secret sauce? Perfecting three factors: uniform particle distribution, efficient light curing, and dense sintering outcomes. Let’s explore how these techniques work in the real world.

1. Stereolithography (SL) -The Original Pioneer

Born from Chuck Hull’s 1986 invention (yes, the same genius behind modern 3D printing!), SL uses UV lasers to harden slurry layer by layer.

Fig1-Schematic diagram of the stereolithography (SL) process. 

-Why It Shines:
Nano Balancing Act: Slurries need 30-60% ceramic nanoparticles by volume—enough to stay sturdy but not clog the laser.
Light's Tricky Path: Many ceramics have problems with scattering. However, silica (SiO₂) is different because it has a good refractive index for light.

Fig. 2. (a) Influence of the refractive index (SiO2 < Al2O3 < ZrO2 < SiC) and (b) ceramic particle concentrations and alumina particle size and solid loading on the photopolymerisation conversion of a ceramic filler containing acrylate

-Real-World Wins:  
A team at Shenzhen University created hollow turbine blades (Fig 3c) and photonic crystals (Fig 3b). They achieved a 97% sintered density, which is a significant improvement for aerospace optics.

Fig. 3. Advanced ceramic parts fabricated using SiO2 via SL: (a) porous bioceramic scaffold; (b) photonic crystals; (c) hollow turbine blade; (d) impeller; (e)–(f): investment casting moulds.

2. Digital light processing (DLP)  

DLP speeds up printing by projecting whole layers at once using micromirror arrays (DMD chips). Changing a flashlight into a laser show feels like a transformation. (Fig4)

Fig. 4. Schematic diagram of the DLP process

-Tech Superpowers:
Vienna University made alumina gears with 25-micron precision (Fig 5a). This is thinner than a human hair! After sintering, the gears reached a strong hardness of 17.5 GPa.

Fig. 5. Samples made with (a)–(b) alumina and (c)–(d) bioglass using the DLP technique

Industry Company uses its LCM technology to make honeycomb catalytic converters (Fig 6a) and auxetic metamaterials (Fig 6d). Auxetic materials expand when you stretch them.

Fig. 6. Sintered alumina parts fabricated using the LCM technique: (a) gear wheels; (b) turbine blade; (c) cellular cube ; (d) auxetic structure with micrometric details

3. Two-photon polymerisation (TPP)-Nanoscale Sculpting with Light

TPP uses near-infrared lasers to start two-photon absorption. This process carves details smaller than a bacterium, achieving sub-micron resolution (Fig 7).

Fig. 7 Schematic diagram of the TPP process, with inset showing that the focus of the laser beam drives the polymerisation process.

-Nano Breakthroughs:
Pham’s team built woodpile-like SiCN structures（Fig8a-f）at 500nm scale (that’s 1/200th the width of your eyelash!) using pre-ceramic polymers.

Fig. 8. SiCN woodpile structure fabricated using the TPP technique: (a) design of the structure; (b) polymeric structure with no filler; (c) ceramic woodpile structure without filler; (d)–(f) ceramic woodpile structure obtained from the mixed resin containing various amounts of silica filler for reduced shrinkage: (d) 20 wt% silica, (e) 30 wt% and (f) 40 wt%. Other 3D ceramic microstructures of spiral shape: (g) micro-tube and (h) micro-cruciform with a twisting angle of 90° between the bottom and top. These were fabricated using a resin containing 40% silica particles (each inset is the top-view of the structure); (i) unpyrolysed SiOC diamond structure fabricated using the TPP technique.

Paired with vapor deposition (CVD/ALD), it creates hollow ceramic nano-lattices（Fig9）—think invisibility cloaks for light waves.

Fig. 9. (a) CAD design of an elliptical hollow-tube nanolattice, with the enlarged part being an octahedron unit cell; (b) SEM image of the FIB-milled edge of a nanolattice. The top left inset shows a transmission electron microscope (TEM) image of the microstructure, revealing nano-size grains. The bottom left inset shows a zoomed image of the tubes; (c) SEM image of the full structure. The scale at the bottom shows a comparison of the approximate sizes of the components of the structure.

4. Inkjet printing (IJP)  
Imagine your desktop printer, but instead of ink, it squirts ceramic-loaded droplets to build parts dot by dot (Fig.10). IJP uses piezoelectric printheads—think microscopic syringes—to jet precise ceramic inks onto a substrate.

Fig. 10. Schematic diagram of the IJP process, with inset showing the printhead jetting droplets at a higher magnification.

-Why It Works:  
​Z-Value Sweet Spot: The ink’s Ohnesorge number inverse (Z value) should be between 1 and 10. If it is too low, droplets will misfire. If it is too high, you will see messy “satellite” splatters.
Beat the Coffee Ring: Just like coffee spills drying with a ring, ceramic p

articles can cluster at droplet edges. Adding PEG or fast-drying agents keeps layers flat and even.

-Real-World Impact:
At Germany’s Karlsruhe Institute of Technology (KIT), IJP-printed silicon nitride (Si₃N₄) gears(Fig.11) hit a flexural strength of 800 MPa—sturdy as aerospace alloys.

Fig. 11. Si3N4 gearwheel fabricated by IJP: (a) green part; (b) sintered part

In your future phone? PZT piezoelectric pillar arrays (Fig. 12a) made by IJP could power new ultrasound sensors. You can use these sensors for medical imaging or gesture control.

Fig. 12. Micro-arrays of pillars: (a) PZT pillars of 1000 layers before sintering; (b) 4000 layers of printing [119]; (c) TiO2 pillars after sintering; (d) highly magnified image of one pillar.

5.Direct ink writing (DIW) ——The Art of Ceramic “Toothpaste”​
DIW works like a high-tech glue gun, squeezing out thick ceramic pastes to create self-supporting structures—perfect for crafting porous scaffolds (Fig.13). The go-to method for designs that laugh in the face of gravity is this.

Fig. 13. Schematic diagram of the DIW process, with inset showing the nozzle extruding ceramic feedstock.

-Innovation Spotlight:

Harvard engineers mixed 47% PZT ceramic slurry to 3D print piezoelectric composites (Fig.14). These materials could revolutionize underwater sonar or even noise-canceling headphones.

Fig. 14. (a) 3D periodic PZT structures made by DIW with concentrated ceramic paste; (b) SEM image showing the detailed microstructure.

In bone regeneration, hydroxyapatite (HA) scaffolds (Fig. 15) have 70% tunable porosity. They serve as tiny jungle gyms, helping bone cells grow where needed.

Fig. 15. Optical micrographs of hydroxyapatite (HA) scaffolds prepared by DIW, with four distinct periodic arrays.

Comparison table of slurry-based ceramic 3D printing technologies

Slurry-based ceramic 3D printing has leaped from lab curiosity to factory floors. DLP and SL are popular for precision components. TPP is changing the rules for nanoscale design. DIW and IJP help create custom functional parts.

Coming Next: In Part 2: Powder & Solid-Based Technologies, we will look at how binder jetting works for rocket nozzles. We will also explore why people use laminated ceramics to restore ancient artifacts. 
Ready to unlock the full potential of ceramic additive manufacturing? Stay tuned!