„Mid-infrared optical coherence tomography as a method for inspection
and quality assurance in ceramics additive manufacturing“
Abstract: In the past decade, significant progress has been made in ceramics additive manufacturing (AM). Material research and the rapid evolution of high-resolution printing technologies enabled the production of high-quality, high-precision, complex structured ceramic objects. In this contribution, we propose a contactless, non-destructive method of mid-infrared optical coherence tomography (mid-IR OCT) for at-line inspection and quality control of AM ceramics. The OCT system operates in the spectral range from 3.15 μm to 4.2 μm featuring extended probing depth into porous ceramics. The spatial resolution of the mid-IR OCT system is suited to most of AM techniques: the axial resolution (determined by the coherence length) is 8 μm; the lateral resolution is around 40 μm (determined by the size of the focused beam). The capabilities of the method are demonstrated by imaging diverse high-scattering single and multi-component samples (in both green and sintered states) fabricated by means of lithography-based ceramics manufacturing. The selected materials are alumina and zirconia, the gold standard in AM. Some features of interest, such as local changes in porosity, surface and sub surface defects and layers structure, were accessed and analyzed.
In the framework of “Work Package 6: Dissemination, Exploitation and Communication (DEC) of Results”, Deliverable D6.2, the article entitled “Mid-infrared optical coherence tomography as a method for inspection and quality assurance in ceramics additive manufacturing” has been published in Open Ceramics and is now accessible online at
„Ceramic-Ceramic Multi-material components by Lithography-based Ceramic Manufacturing (LCM)“
Abstract: The continual need for new materials and their combinations that can tolerate different conditions by providing properties and functions at different positions led to the design of multi-material components. Significant developments in manufacturing technologies especially in additive manufacturing (AM) enable us nowadays to manufacture multi-materials that can improve functionality and performance by combining different material properties in a single component. Lithography-based Ceramic Manufacturing (LCM), a method developed by Lithoz GmbH as an enhancement of stereolithography and digital light processing (DLP) technology, offers layer-by-layer printing by curing a photosensitive formulation with a mask-exposure process using the concept of DLP in the required areas through selective light exposure. A newly developed 3D printer type allows the deposition of multi-materials by simultaneous processing of two photocurable feedstocks.
Various methodologies have been introduced that enable multi-layered and functionally graded ceramic-ceramic multi-material combinations that have different compositions, microstructure, and porosity.
This study investigates the performance of printing methodologies of ceramic-ceramic multi-materials in terms of printability, precision, and functionality.
In the framework of “Work Package 6: Dissemination, Exploitation and Communication (DEC) of Results”, Deliverable D6.2, the poster entitled “Ceramic-Ceramic Multi-material components by Lithography-based Ceramic Manufacturing (LCM)” has been presented at 23. Symposium Verbundwerkstoffe und Werkstoffverbunde, in Leoben, Austria.
„Lithography-based additive manufacturing of porosity graded alumina“
Abstract:With the developments in manufacturing technologies, interest on porosity graded alumina ceramics has increased for applications such as thick barrier coating, cores for precision casting and biocompatible implants.
Lithography-based Ceramic Manufacturing (LCM) offers high quality and near-net manufacturing of complex ceramic components with high resolution. Multi-material LCM printing setup can overcome the main problems of conventional manufacturing techniques for fabrication of porosity graded alumina with desired microstructure and gradient architecture (i.e., gradient direction, fraction, type). Two-vat system in the newly developed multi-material LCM printer setup enables not only assigning one material to any desired layer but also use of different materials in each layer by assigning the respective materials to selected pixels of the layer image.
This article introduces methodologies for the fabrication of porosity graded alumina ceramics (PGACs) with continuous and discrete porosity transitions zones by combining sacrificial templating and LCM. It is illustrated how the properties of the slurry and the desired gradient architecture play an important role for the selection of suitable method.
In the framework of “Work Package 6: Dissemination, Exploitation and Communication (DEC) of Results”, Deliverable D6.2, the article entitled “Lithography-based additive manufacturing of porosity graded alumina” has been published in Additive Manufacturing Letters and is now accessible online at
„Vat Photopolymerization Additive Manufacturing of Functionally Graded Materials: A Review“
Abstract: Functionally Graded Materials (FGMs) offer discrete or continuously changing proper- ties/compositions over the volume of the parts. The widespread application of FGMs was not rapid enough in the past due to limitations of the manufacturing methods.
Significant developments in manufacturing technologies especially in Additive Manufacturing (AM) enable us nowadays to manufacture materials with specified changes over the volume/surface of components. The use of AM methods for the manufacturing of FGMs may allow us to compensate for some drawbacks of conventional methods and to produce complex and near-net-shaped structures with better control of gradients in a cost-efficient way. Vat Photopolymerization (VP), a type of AM method that works according to the principle of curing liquid photopolymer resin layer-by-layer, has gained in recent years high importance due to its advantages such as low cost, high surface quality control, no need to support structures, no limitation in the material.
This article reviews the state-of-art and future potential of using VP methods for FGM manufacturing. It was concluded that improvements in printer hardware setup and software, design aspects and printing methodologies will accelerate the use of VP methods for FGMs manufacturing.
In the framework of “Work Package 6: Dissemination, Exploitation and Communication (DEC) of Results”, Deliverable D6.2, the review article entitled “Vat Photopolymerization Additive Manufacturing of Functionally Graded Materials: A Review” has been published in the Journal of Manufacturing and Materials Processing and is now accessible online at