Date of Award
2026-08-01
Degree Name
Doctor of Philosophy
Department
Mechanical Engineering
Advisor(s)
Eric MacDonald
Abstract
Lithography-based additive manufacturing provides a route to fabricating ceramic and metallic components with complex geometry, fine features, and application-specific functionality. Realization of such components in functional systems, however, requires control over architecture, dimensional accuracy, thermal processing, and joining. This dissertation addresses these interconnected requirements through studies of vat-photopolymerization-derived alumina and Kovar, with emphasis on architected ceramic structures, fine-feature dimensional fidelity, ceramic joining, and orientation-dependent metal properties. The first part of this work examines additively manufactured alumina lattices for electromagnetic applications. Vat photopolymerization enables fabrication of functionally graded ceramic volumes in which local density is controlled through lattice architecture and strut dimensions. Because the ratio of ceramic material to interstitial space governs the effective permittivity of the structure, this approach offers a pathway to graded dielectric components in low-loss alumina. Four lattice architectures—Oct Vertex Centroid, IsoTruss, Fluorite, and Kelvin—were fabricated to assess printability at unit cell dimensions relevant to radio-frequency operation. The results demonstrate that periodic alumina lattices with spatially variable density can be manufactured over a range suitable for future graded-permittivity ceramic lens structures. The second part investigates the dimensional response of fine features in lithography-based ceramic manufacturing of alumina. Feature dimensions near the native optical resolution are influenced by projected pixel size, exposure conditions, and interactions with surrounding geometry. To characterize these effects, test structures were fabricated on a system with a projected pixel size of 40 𝜇m × 40 𝜇musing a 94%alumina feedstock. Initial measurements showed that low-height features were strongly affected by substrate proximity, leading to oversizing of vi nominally small features. A stair-step metrology specimen was then developed to reduce substrate influence and improve measurement throughput. A design-of-experiments study showed that both projected energy and contour offset significantly affected realized feature width, with negative contour offset improving dimensional accuracy. These relative trends persisted after sintering, indicating that process-dependent dimensional behavior in the green state remains predictive of final dimensions. The third part evaluates the suitability of additively manufactured high-purity alumina for ceramic-to-ceramic brazing. Alumina fabricated from Lithoz Lithalox 350 was preconditioned, debound, and sintered, then characterized for dimensional stability, surface roughness, density, coefficient of thermal expansion, and surface chemistry. The sintered material exhibited an average density of 3.767g/cm3, or approximately 94.5%of theoretical density, with surface roughness compatible with the braze foil thicknesses used. Surface analysis showed a predominantly alumina composition with trace Si and Ca impurities. Brazing was demonstrated using Morgan 598B + nickel oxide + Cu, Ceronics CE-142 + nickel oxide + Cu, and direct TiCuSil active brazing. Modified ASTM F19 tensile button testing yielded maximum forces of 1224.24 N, 4744.16 N, and 2984.45 N, respectively, and all methods produced hermetic joints. These results demonstrate that vat-photopolymerized high-purity alumina can be successfully joined and suggest that silica-containing metallization routes may improve bond strength. The final part considers lithography-based metal manufacturing of Kovar, a Fe-Co-Ni alloy used in hermetic packaging because of its thermal expansion compatibility with glass and ceramics. Tensile specimens were fabricated using an Incus Hammer Lab35 system from a feedstock containing 55%by volume Kovar powder with 25 𝜇mparticle size and a 25 𝜇mlayer thickness, and were printed in flat, side, and vertical orientations. After thermal processing in open- vii atmosphere and hydrogen furnaces, specimens were evaluated for tensile behavior, density, and ductility. Build orientation significantly affected final properties: flat-built specimens showed the highest average strength and density, side-built specimens the greatest ductility, and vertical-built specimens the lowest overall performance. Taken together, these studies show that the performance of lithography-based additively manufactured ceramic and metallic components is governed by linked phenomena spanning architectural design, exposure-controlled feature formation, thermal densification, surface condition, and joining behavior. This dissertation establishes a framework for the development of ceramic–metal systems produced by vat photopolymerization-derived processes and provides a technical basis for applications requiring graded functionality, dimensional precision, hermetic sealing, and thermomechanical compatibility.
Language
en
Provenance
Received from ProQuest
Copyright Date
2026-08
File Size
146 p.
File Format
application/pdf
Rights Holder
Dale Evan Cillessen
Recommended Citation
Cillessen, Dale Evan, "Lithography-Based Additive Manufacturing Of Ceramics And Metals For Structural Integrity, Joining, And Multi-Material Integration" (2026). Open Access Theses & Dissertations. 4655.
https://scholarworks.utep.edu/open_etd/4655