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The purpose of this paper is to develop the relationships between ceramic stereolithography (SL) process parameters and curing characteristics of a ceramic suspension. A recently developed photocurable aqueous-based silica suspension with high solid loading (50 vol%) was employed to run small batch experiments. Basic structural building units inclu...
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... fabricate the single cured lines, the silica suspen- sion was irradiated under a laser of 355 nm wave- length with different laser power and scanning velocities corresponding to a series of density of energy. The observed and measured results of cured line and section profiles are given in Fig. 7 and Table 2 respectively. The results suggest that when the laser power is fixed, the dimensions (C d and L w ) of cross-sections are both decreasing as the scanning velocity is increasing, namely the density of energy is reducing with equation (2). ...
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The negative effect of inner stresses on the ceramic green body formed by gelcasting is discussed. It is found that a proper amount of hydroxyethyl acrylate (HEA) added into the concentrated suspension can adjust polymer network structure and thus reduce the inner stresses and cracking in the ceramic green body. The debindering time of large cerami...
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... This technology served various industries by facilitating the creation of parts with complex designs, including integrally cored casting molds. Chen's group realized several advanced fused silica ceramic parts ranging from scaffolds to casting molds [23,44,45]. Figure 9 shows the basic setup of the SLS 3D silica ceramics printing. ...
3D printing enables the creation of complex and sophisticated designs, offering enhanced efficiency, customizability, and cost-effectiveness compared to traditional manufacturing methods. Ceramics, known for their heat resistance, hardness, wear resistance, and electrical insulation properties, are particularly suited for aerospace, automotive, electronics, healthcare, and energy applications. The rise of 3D printing in ceramics has opened new possibilities, allowing the fabrication of complex structures and the use of diverse raw materials, overcoming the limitations of conventional fabrication methods. This review explores the transformative impact of 3D printing, or additive manufacturing, across various sectors, explicitly focusing on ceramics and the different 3D ceramics printing technologies. Furthermore, it presents several active companies in ceramics 3D printing, proving the close relation between academic research and industrial innovation. Moreover, the 3D printed ceramics market forecast shows an annual growth rate (CAGR) of more than 4% in the ceramics 3D printing market, reaching USD 3.6 billion by 2030.
... In this approach, two technologies are used: (i) indirect, where a template is designed, printed from a polymer resin, filled with an appropriate mixture, and finally burnt out [27][28][29], and (ii) direct, where instead of pure polymer resin, its mixture with various ceramic components, e.g. alumina [30,31], silica [32][33][34], hydroxyapatite [35] or zirconium [30,36], is used. The basic components included in a ceramic resin, in addition to ceramic components, are a solvent, photoinitiator, dispersant, absorber, and mono-or difunctional acrylates [36,37]. ...
... The basic components included in a ceramic resin, in addition to ceramic components, are a solvent, photoinitiator, dispersant, absorber, and mono-or difunctional acrylates [36,37]. Additionally, researchers use different types of photoinitiators for the resins they have developed, e.g., Irgacure 184 [34], Irgacure 651 [36], DMPA [35], and Photocure 1173 [32,33]. The developed ceramic resin compositions can also be found in the patent literature [38]. ...
Several composite organic-inorganic resins dedicated to 3D printing using Digital Light Processing (DLP) technology containing nano- and micro-structured corundum as well as corundum/kaolin mixtures were prepared and characterised in terms of their rheology and stability. Using these resins, short monoliths were printed using the DLP technology at a resolution of x:y:z = 30/30/50 microns. After thermal pre-treatment, the printed materials were studied by X-ray fluorescence (XRF), X-ray diffraction (XRD), and scanning electron microscopy (SEM) with energy dispersive spectroscopy (EDS). Based on the selected monoliths, MnOx- and Na2WO4-containing catalysts were prepared by two-step impregnation and tested in the oxidative coupling of methane (OCM) at 820 °C using a ratio of methane/oxygen of 3.8/1. The maximum conversion of methane (28%) and total conversion of oxygen (100%), as well as stable selectivity to ethane (22%) and ethylene (44%), were achieved using three short monoliths (GHSV = 7676 h⁻¹). A further enhancement of the number of monoliths influenced only the COx and C3 selectivity. Moreover, a comparative study of monolithic and powder samples with identical compositions revealed that the monolithic catalyst, the yield of C2–C3 hydrocarbons is slightly lower (1–2%) but at a 3–4 times lower pressure drop.
... Unfilled photopolymer resins are homogeneous and relatively transparent to the incoming UV laser beam. The cure depth is relatively large in unfilled resin because the UV laser light is attenuated only due to the absorbing agent like photoinitiators or dyes, as depicted in Fig. 2. The cured profile looks like a narrow bullet-shaped structure, whose cured depth (C d ) is greater than the cure width (C w ) [23]. C d for unfilled resin can be expressed as Eq. ...
This paper aims to investigate the novel Poly(ethylene glycol) diacrylate (PEGDA)/bioceramics composites fabricated using stereolithography (SLA) for load-bearing tissue engineering applications. PEGDA hydrogel resins loaded with 1 wt% content of hydroxyapatite (HAP), calcium phosphate (CaP), and graphite (Gr) have been developed and characterized by rheological and sedimentation tests. PEGDA/bioceramics composites were characterized by mechanical, tribological, physical, and biological tests. It was found that PEGDA/HAP composite has a high tensile strength (79.1% improvement) and flexural strength (219.4% improvement), and PEGDA/Gr composite has high compressive strength (150.3% improvement) compared to unfilled PEGDA. The fractography analysis revealed that brittle fracture occurred in PEGDA and PEGDA/bioceramics composites specimens. Besides this, PEGDA and its composites are found to be thermally stable up to the temperature of ~187°C. Among all, PEGDA/Gr composite showed high compressive strength, wear resistance, low friction force, and high wettability. Additionally, PEGDA/Gr composite was found to be non-toxic, supported cellular growth, and showed similar biocompatibility as unfilled PEGDA and other composites. Thus, a comparative study has investigated the suitability and feasibility of PEGDA/bioceramic composite for tissue engineering applications.
... Compared to other printing techniques, SL-printed parts achieve a higher degree of details for reasons that the UV light can be scanned with high accuracy and thus sharper and cleaner surfaces can be obtained [178]. The minimum feature size is determined by the spot size of the UV light [179]. ...
Artificially structured ceramic components with extraordinary properties are of immense demand in various industries. Additive manufacturing (AM) or 3D printing technologies are promising for the fabrication of ceramic components. However, printing of ceramics directly from their raw powders is a daunting task and requires multistep processing. Preceramic polymers (PCPs) offer an attractive pathway towards AM of preceramic structures featuring heterogeneous architectures and their direct conversion to polymer-derived ceramics (PDCs) – the corresponding ceramics. This review reports a detailed summary of recent research progress on the additive manufacturing of PCPs and the corresponding PDCs manufactured for different applications. The approaches towards the synthesis of various PCPs are discussed along with easily tunable chemical formulations that can be employed in AM processes. Further, the review discusses conventional PDC technology as well as AM technologies that can be employed with PCPs and the associated superiorities and drawbacks in comparison to powder-based ceramic 3D printing. Complex-shaped PDC structures and their properties and potential applications are also discussed. Overall, this review illustrates the AM capabilities of PCPs for cost-effective fabrication of advanced ceramics with high resolution, superior performance, lower environmental impact and new functionalities.
... Many studies have established the link between the development of low viscosity inks and an adequate curing depth, by investigating the influence of the photoinitiator concentration [12,13], particle size and particle size distribution [14,15], volume fraction of ceramic powders [16,17], and curing energy vs. C d [18,19] of ceramic suspensions. In the past decade, a few researchers [20][21][22][23][24][25] focused on preparing novel low viscosity photosensitive ceramic suspensions loaded with various types of ceramic powders (i.e., SiO 2 , Al 2 O 3 , ZrO 2 , SiC or SiOC) in order to design formulations suitable for DLP or SLA 3D printing. ...
The primary objective of this study is to demonstrate the possibility of developing silica, alumina, and zircon-based photocurable ceramic suspensions that can be used for visible light photopolymerization (> 450 nm) and to optimise the binder formulations for the purpose of LCD-based ceramic 3D printing applications. Reference ceramic components for this work are ceramic cores employed in the investment casting of high-pressure turbine blades and vanes. Arguably, one of the most critical steps in photoinduced ceramic 3D printing is developing suitable ceramic suspensions, having high ceramic loading, low viscosity, and short curing times. Ceramic suspensions with four different novel binder formulations and commercial ceramic powders used in core manufacturing (SiO2, Al2O3 and ZrSiO4) were investigated to achieve the best trade-off between: (1) their curing performance (cure depth and curing speed), (2) rheological properties of the binder mixtures at the solid loadings of 60 vol.% for SiO2, 55 vol.% for ZrSiO4, and 45 vol.% for Al2O3; and (3) the green body mechanical properties of the mixtures after printing. The effect of ceramic particles on the selected binders was examined individually, and the correlation between cure depth (Cd), volumetric loading, and curing speed are evaluated. The results show all binders designed in this study provide an adequate cure depth, even at high ceramic loadings. When the curing behaviour of all unloaded binder mixtures from the previous study [1] compared with the 10 vol.% SiO2 loaded mixtures, the cure depth of all formulated binder mixtures increased 50–55 % and the curing thickness of 60 vol.% SiO2 loaded suspensions were still slightly higher than their unloaded counterparts. The rheology outcomes indicate that lower viscosity binders always result in lower viscosity of the ceramic loaded inks, even without taking the effect of dispersants into account. Besides, the addition of N-Vinyl-2-Pyrrolidone (NVP) monofunctional monomer to the binder mixtures significantly reduces the viscosity and changes the normally linear relationship of the mix viscosity and its silica loading content. Among the binder formulations loaded with 60 vol.% of SiO2, the formulation providing the lowest viscosity and highest mechanical property consists of 5 wt.% of NVP, 45 wt.% of HDDA and 50 wt.% of Photocentric 34 resin. Although this binder mixture showed the highest green flexural strength when loaded by 55 vol.% ZrSiO4, all other mixtures loaded with zircon flour also demonstrated a near-fluid behaviour, below 200 s−1. In Al2O3 loaded mixtures, the HDDA di-functional binder formulations present lowest viscosity and the di- and multifunctional monomer blends (HDDA-Photocentric27) showed the highest mechanical properties when used in a 50/50 ratio. This work summarises the best binder choices for silica, alumina and zircon based ceramic suspensions used in core printing for investment casting applications through LCD screen printing.
... As a result of these characteristics, SLA has become one of the most essential and widely used AM technologies for manufacturing of zirconia devices [23,24]. The SLA of ceramics begins with the incorporation of fine ceramic particles as small as micro/nanometers into the photocurable solution [25,26]. After the liquid has been thoroughly dispersed in the medium with the help of necessary surfactants and additives, it creates a ceramic suspension. ...
... nologies for manufacturing of zirconia devices [23,24]. The SLA of ceramics begins w the incorporation of fine ceramic particles as small as micro/nanometers into the pho curable solution [25,26]. After the liquid has been thoroughly dispersed in the mediu with the help of necessary surfactants and additives, it creates a ceramic suspension. ...
Additive manufacturing (AM) has many advantages and became a valid manufacturing technique for polymers and metals in dentistry. However, its application for dental ceramics is still in process. Among dental ceramics, zirconia is becoming popular and widely used in dentistry mainly due to its outstanding properties. Although subtractive technology or milling is the state of art for manufacturing zirconia restorations but still has shortcomings. Utilizing AM in fabricating ceramics restorations is a new topic for many researchers and companies across the globe and a good understanding of AM of zirconia is essential for dental professional. Therefore, the aim of this narrative review is to illustrate different AM technologies available for processing zirconia and discus their advantages and future potential. A comprehensive literature review was completed to summarize different AM technologies that are available to fabricate zirconia and their clinical application is reported. The results show a promising outcome for utilizing AM of zirconia in restorative, implant and regenerative dentistry. However further improvements and validation is necessary to approve its clinical application.
... In fact, there are already reports of ceramic systems with complex designs and high resolutions, such as those recently reviewed by Chen et al. [30]. In this summary, you can find reports of the additive manufacturing of structured monoliths, scaffolds and parts with materials such as B 4 C [31], CaCO 3 [32], Al 2 O 3 [33], bio-active glass [34,35], Al 2 O 3 +-ZrO 2 [32], SiC [36], hydroxyapatite [37], SiO 2 [38], TiO 2 [39], SiCN [40], SiOC [41], Si 3 N 4 [42], 3YSZ [43,44], Ti 3 SC 2 [45], amongst others. However, the vast majority of these studies focus on the mechanical properties of prints with applications in the engineering field, the generation of biocompatible parts, but not with catalysis. ...
Catalysis, a driving force of the chemical industry is increasingly being influenced by additive manufacturing. The link between them is based on the need to intensify catalytic processes in order to make them more efficient and sustainable. Additive manufacturing can satisfy such a need, generating devices with an advanced design, easy production, and great adaptation, in addition to their catalytic functionality. The exponential growth of examples reported on the application of 3D-printing in catalysis has led to the need to compile and analyse these cases and thus establish, through this review, the most in-depth analysis done to date.
The manuscript includes a brief background of the history of additive manufacturing and the classification of the different printing techniques. Subsequently, it identifies the intensification of processes, among other aspects, as the key for understanding the union of additive manufacturing and catalysis. Then, it explores in detail how such a combination occurs, establishing the most comprehensive classification to date between the two large groups of printable devices with catalytic properties. Finally, a series of perspectives are proposed in which the most probable courses of new advances in this field of research are identified.
... Additionally, the viscosity is very low, with a value of about 1000 mPa•s, even with highly filled slurries. With such slurries, high curing depths of up to 300 μm and a resolution of 100 μm are possible [33,34]. The inclination angle should not be larger than 30° to reduce delamination and the surface roughness considering the ladder effect [35]. ...
... For a lower exposure dose, the 3D structures which were fabricated resemble well the designed structures. However, the structures are deformed if higher exposure doses beyond 35 mW average laser power are used [34]. A closer look at the interface substrate/3D structures shows that below 25 mW compressive stresses play a major role for the delamination process. ...
Additive manufacturing is well established for plastics and metals, and it gets more and more implemented in a variety of industrial processes. Beside these well-established material platforms, additive manufacturing processes are highly interesting for ceramics, especially regarding resource conservation and for the production of complex three-dimensional shapes and structures with specific feature sizes in the µm and mm range with high accuracy. The usage of ceramics in 3D printing is, however, just at the beginning of a technical implementation in a continuously and fast rising field of research and development. The flexible fabrication of highly complex and precise 3D structures by means of light-induced photopolymerization that are difficult to realize using traditional ceramic fabrication methods such as casting and machining is of high importance. Generally, slurry-based ceramic 3D printing technologies involve liquid or semi-liquid polymeric systems dispersed with ceramic particles as feedstock (inks or pastes), depending on the solid loading and viscosity of the system. This paper includes all types of photo-curable polymer-ceramic-mixtures (feedstock), while demonstrating our own work on 3D printed alumina toughened zirconia based ceramic slurries with light induced polymerization on the basis of two-photon absorption (TPA) for the first time. As a proven exemplary on cuboids with varying edge length and double pyramids in the µm-range we state that real 3D micro-stereolithographic fabrication of ceramic products will be generally possible in the near future by means of TPA. This technology enables the fabrication of 3D structures with high accuracy in comparison to ceramic technologies that apply single-photon excitation. In sum, our work is intended to contribute to the fundamental development of this technology for the representation of oxide-ceramic components (proof-of-principle) and helps to exploit the high potential of additive processes in the field of bio-ceramics in the medium to long-term future.
... Despite the advances that have been made by compromising printing parameters, only about 50 vol% of the ceramic solid content in the slurries is normally found suitable for incorporating the stated properties (e.g., pore reduction, high density, and low shrinkage) into the finished parts [26,27]. In fact, high solid loading (≥ 50 vol%) can decrease flow ability, increase viscosity, cause inhomogeneity, and hence reduce suitability of the slurry for efficient polymerization [10,28]. ...
Conversion of inorganic–organic frameworks (ceramic precursors and ceramic–polymer mixtures) into solid mass ceramic structures based on photopolymerization process is currently receiving plentiful attention in the field of additive manufacturing (3D printing). Various techniques (e.g., stereolithography, digital light processing, and two-photon polymerization) that are compatible with this strategy have so far been widely investigated. This is due to their cost-viability, flexibility, and ability to design and manufacture complex geometric structures. Different platforms related to these techniques have been developed too, in order to meet up with modern technology demand. Most relevant to this review are the challenges faced by the researchers in using these 3D printing techniques for the fabrication of ceramic structures. These challenges often range from shape shrinkage, mass loss, poor densification, cracking, weak mechanical performance to undesirable surface roughness of the final ceramic structures. This is due to the brittle nature of ceramic materials. Based on the summary and discussion on the current progress of material–technique correlation available, here we show the significance of material composition and printing processes in addressing these challenges. The use of appropriate solid loading, solvent, and preceramic polymers in forming slurries is suggested as steps in the right direction. Techniques are indicated as another factor playing vital roles and their selection and development are suggested as plausible ways to remove these barriers.
... The thickness of the cured portion can then be measured with a micrometer to acquire the numerical value for curing depth C d . The C d data for different resin formulations was plotted against ln(E max ) to obtain a slope corresponding to the penetration depth (D p ) and an x-axis intersection point corresponding to the critical energy (E c ) [19,29]. ...
Hierarchically porous structures are important in adsorption applications and can be used in gas treatment. Hierarchy in adsorbents offers flow channels on different scales, resulting in fast gas flow into a structure. Additive manufacturing, a technology capable of forming intricate geometries, was seen as a potential method to form porous adsorption structures. Stereolithography was chosen as the fabrication method for hierarchically porous zeolite structures because of its high resolution and superior forming capability. The focus of this study was on tailoring the properties of light-cured resin to maximize stability during shaping and shape retention in the debinding stage. Successful slurry preparation was required for demonstrating that monoliths with channel geometry and retained adsorption properties can be manufactured with stereolithography. The final printed structures exhibited hierarchical porosity consisting of flow channels, macropores between the primary particles and the characteristic microporosity of zeolite framework. The structure was manufactured by using blue light to cure layers of resin containing ZSM-5 zeolite. An appropriate debinding heat-treatment cycle was generated based on the TGA and DSC thermal analysis results. The properties of the porous structure were analysed by comparing the BET surface area, XRD patterns and SEM images of as-received powder and a debound piece. The measured BET adsorption properties of the final monoliths remained comparable to the as-received ZSM-5 powder. Based on this study, stereolithography can be utilized to manufacture porous zeolite structures.
