Multi-material glass additive manufacturing: a review of materials, techniques, and integration challenges

Abstract Glass offers unique advantages such as high optical transparency, thermal stability, and chemical resistance, making it indispensable in optics, microelectronics, sensing, and biomedical applications. However, its high melting point, brittle nature, and incompatibility with traditional manufacturing methods present significant fabrication challenges. Additive manufacturing (AM) introduces new possibilities for the glass industry by enabling the fabrication of customised, complex 3D structures and the integration of glass with other compatible materials. In particular, multi-material glass additive manufacturing (MMGAM) has emerged as a promising frontier, enabling both the spatial tuning of glass composition, dopants, and functionalities, as well as the co-fabrication of glass with dissimilar materials, such as polymers, metals, or ceramics, within a single component using integrated AM platforms. This paper provides a comprehensive overview of the current state of MMGAM, structured around four key themes: (i) key material properties and interfacial compatibility considerations, (ii) AM techniques adapted for multi-material glass systems, (iii) material combinations and strategies for functional integration, and (iv) future challenges and research directions. Particular emphasis is placed on the challenges of interfacial bonding, material compatibility, and the formulation of printable glass systems suitable for co-processing with other materials. The review explores recent strategies for enabling multifunctional, integrated architectures that combine optical, structural, or chemical functionalities within a single component. By synthesising current advances and outlining key research gaps, this work aims to accelerate the development and broader adoption of MMGAM technologies.