| Title |
Curing Behavior and Stacking Stability of Photocurable Si3N4 Slurries for DLP 3D Printing |
| Authors |
이민호(Min-Ho Lee) ; 이재승(Jae-Seung Lee) ; 안종필(Jong-Pil Ahn) ; 소성민(Sung Min So) ; 김진우(Jin-Woo Kim) ; 김택윤(Tack-yoon Kim) ; 박주석(Joo-Seok Park) ; 이희수(Heesoo Lee) |
| DOI |
https://doi.org/10.3365/KJMM.2025.63.10.839 |
| ISSN |
1738-8228(ISSN), 2288-8241(eISSN) |
| Keywords |
Ceramic 3D printing; Digital light processing; Silicon nitride; Photocurable slurry; Stacking stability |
| Abstract |
Digital light processing (DLP) 3D printing has emerged as a promising technique for fabricating highprecision
ceramic components, including biomedical implants. However, achieving high-strength silicon nitride
(Si3N4) spinal implants via DLP remains challenging due to slurry formulation constraints. This study optimizes
the formulation of a photocurable Si3N4 slurry to enable DLP-based printing of spinal implant components. The
effects of monomer composition and photoinitiator content on slurry viscosity and stability were evaluated.
Slurries with only monomer A exhibited post-printing warpage, while those with only monomer B showed rapid
polymerization shrinkage, causing delamination. In contrast, a 1:1 weight ratio blend of monomers A and B with
3 wt% photoinitiator (M-AB-3) maintained viscosity stability within 3% over 24 h and showed excellent shape
fidelity. The flexural strength of the green body increased to 122 MPa when 8 wt% oligomer A was added, while
viscosity rose to ~9,100 cP. A low-viscosity oligomer B was added to reduce viscosity. A formulation with 4 wt%
oligomer A and 4 wt% oligomer B achieved optimal performance, with ~7,000 cP viscosity and 154 MPa green
strength. Based on this optimized resin, ceramic solid loading was increased stepwise, and 66 wt% was
determined to be the maximum printable content. Printed specimens were sintered under nitrogen (1800 oC,
1 MPa), resulting in a relative density exceeding 99%, flexural strength of 1,070 MPa, Vickers hardness of
1,670 HV, and fracture toughness of 7.3 MPa·m1/2. These results confirm that the developed slurry enables stable
high-solid loading and yields high-performance Si3N4 components suitable for spinal implant applications. |