A research team has used advanced 3D printing techniques to develop low-temperature, "sinterless" silica glass. They converted 3D-printed objects into silica glass structures at significantly lower temperatures than traditional sintering, offering a promising route for efficient and precise glass manufacturing.
Their research is published in the journal Polymers on December 1, 2025.
The team used polyhedral oligomeric silsesquioxane (POSS)-based resin in this project. This work with the POSS resin has potential applications, including the production of multi-scale devices, such as microfluidic devices and optical components, and hybrid processing with semiconductors and MEMS and photonic devices.
"The key takeaway is that resin chemistry can make low‑temperature, sinterless silica glass 3D printing practical and scalable by designing a low‑viscosity organic-inorganic hybrid resin with higher silica content," said Shoji Maruo, a faculty of engineering professor at YOKOHAMA National University. Sintering is a heat treatment process where materials are compacted and formed into a solid mass. In a sinterless process, the resin is converted into its final solid form without the use of high temperatures. The team cut calcination shrinkage to ~36%, vs. ~42% in prior POSS systems. This reduces cracking and warping and enables transparent silica conversion at ~650–700 °C using both high‑resolution two‑photon polymerization and lower‑cost single‑photon stereolithography. This resin's adaptability allows flexible size adjustments in the production of multiscale devices. In addition, it maintains high precision from the micron scale to macroscopic dimensions.
Glass is a material with excellent heat resistance, durability, and optical transparency. Recent advances in 3D printing technology have enabled the fabrication of complex shapes that are difficult to achieve using traditional forming methods such as glassblowing. In particular, stereolithography, a 3D glass-printing technique which offers the highest level of manufacturing precision, is expected to enable the production of high-value-added optical components and microfluidic circuits. Stereolithography is capable of ultrahigh precision. However, glass fabrication using stereolithography traditionally requires a post-treatment process of sintering at temperatures above 1000°C to remove organic components from a resin ink containing silica nanoparticles and obtain transparent glass structures.
Recent advances in 3D printing of silica glass have highlighted the limitations of conventional stereolithography, which requires the high-temperature sintering and often uses slurry-based materials. To address these limitations, a sinterless approach using POSS-based resin has gained attention among researchers. These approaches are capable of forming transparent fused silica at only 650°C. However, these earlier POSS-based systems suffered from high shrinkage because of the addition of organic monomers to reduce the resin viscosity. Monomers are special molecules that connect with other similar molecules to form long networks. They are the simple building blocks that form polymers. The team synthesized this novel low-viscosity polymerizable POSS resin without additional monomers. The resin maintained its sinterless properties while reducing shrinkage.
The POSS resin is applied to single-photon polymerization using blue lasers or ultraviolet lamps. This holds potential for the fabrication of microfluidic devices by encapsulating a 3D-printed mold in the POSS resin, followed by exposure and calcination to remove the 3D-printed mold. This molding technique does not require cleaning of uncured resin inside the microchannel, which makes it easier to create fine, complex microchannels than methods that directly create microchannels using 3D printing.
"In this study, we developed a novel organic-inorganic hybrid POSS-based resin with high silica content and low viscosity without using silica nanoparticles and demonstrated glass 3D printing using low-temperature calcination (~650-700°C)," said Maruo.
Looking ahead to future research, the team's ultimate goal is to rapidly fabricate centimeter-sized transparent glass 3D structures with submicron resolution by combining two-photon lithography and single-photon stereolithography for multiscale 3D printing. This kind of multiscale 3D printing will enable the fabrication of high-precision lenses, multifunctional freeform optics components, and complex microfluidic circuits. "Furthermore, we aim to realize a low-temperature (~650-700°C) silica additive manufacturing platform that will enable hybrid integration with semiconductor, MEMS, and photonic devices," said Maruo.
The research team includes Liyuan Chen, Masaru Mukai, Yuki Hatta, Shoma Miura, and Shoji Maruo from YOKOHAMA National University.
This research was funded by a Japan Science and Technology Agency (JST) CREST grant.
