Digital Light Processing Technology Research Articles

Effects of ZrSiO4 content on properties of SiO2-based ceramics prepared by digital light processing

SiO2-based ceramic cores are widely used in the preparation of gas turbine engine hollow blades due to their excellent chemical stability and easy removal after casting. In this paper, ZrSiO4 reinforced SiO2-based ceramics were fabricated using digital light processing (DLP) technology. The results showed that the addition of ZrSiO4 reduced the cure depth due to its high UV light absorptivity and refractive index. When the content of ZrSiO4 increased to 15 wt%, the cristobalite content reached the maximum, and radial shrinkage reached the minimum of 1.4%. ZrSiO4 grains could hinder the propagation of cracks, enhancing the room-temperature flexural strength. At 1550 °C, fracturing across SiO2 grains in SiO2-based ceramics led to the great improvement of high-temperature flexural strength. When the content of ZrSiO4 reached 15 wt%, the flexural strength at room temperature and high temperature was 11.5 MPa and 36.7 MPa, respectively. Therefore, the SiO2-based ceramics prepared using DLP technology have good room temperature and high temperature properties, and are expected to be used for hollow blade casting.

3D printing of flexible strain sensor based on MWCNTs/flexible resin composite

The flexible strain sensor is an indispensable part in flexible integrated electronic systems and an important intermediate in external mechanical signal acquisition. The 3D printing technology provides a fast and cheap way to manufacture flexible strain sensors. In this paper, a MWCNTs/flexible resin composite for photocuring 3D printing was prepared using mechanical mixing method. The composite has a low percolation threshold (1.2% ωt). Based on the composite material, a flexible strain sensor with high performance was fabricated using digital light processing technology. The sensor has a GF of 8.98 under strain conditions ranging between 0% and 40% and a high elongation at break (48%). The sensor presents mechanical hysteresis under cyclic loading. With the increase of the strain amplitude, the mechanical hysteresis becomes more obvious. At the same time, the resistance response signal of the sensor shows double peaks during the unloading process, which is caused by the competition of disconnection and reconstruction of conductive network in the composite material. The test results show that the sensor has different response signals to different types of loads. Finally, its practicability is verified by applying it to balloon pressure detection.

Additive manufacturing of graphene oxide/hydroxyapatite bioceramic scaffolds with reinforced osteoinductivity based on digital light processing technology

In the field of bone tissue engineering, porous hydroxyapatite (HA) bone repair scaffolds with controlled architecture and porosity are challenging to manufacture and lack sufficient osteoinductive activity, which limit its wider clinical application. This study fabricated porous graphene oxide (GO)/HA composite ceramic scaffolds using digital light processing (DLP) technology. The properties of the composite ceramic slurry and the process parameters of curing, degreasing, and sintering were initially examined to ensure molding accuracy. The research showed that a small amount of GO (0.1–0.4 wt%) could better maintain the pore structure and improve the mechanical properties of composite ceramics. Porous scaffolds with pore sizes of 300–400 μm were prepared for co-culture with rat bone marrow mesenchymal stem cells to detect biocompatibility. The results showed that all scaffolds have no cytotoxicity. Compared with HA, the GO/HA ceramic scaffold significantly promoted the cell adhesion, proliferation, and expression of osteogenesis-related genes; GO (0.1–0.2 wt%) /HA scaffolds exhibited superior alkaline phosphatase activity and more effective bone mineralization, showing enhanced osteoinductivity. The porous GO/HA composite scaffold fabricated by DLP presented a strong potential for repairing bone defects.

Influence of a non-reactive additive on the photocuring and 3D-VAT printing processes of PEGDA: Complementary studies

Photopolymerization processes are currently-one of the key methods for obtaining functional materials, and the possibility of applying this processes to additive technologies opens up new opportunities, especially for the medical market. 3D-VAT printing, including techniques such as digital light processing (DLP) and stereolithography (SLA), makes it possible to obtain materials with the desired geometry, high optical resolution and rapid layer-by-layer production time, which was not previously possible with classical techniques used in biomedicine. Therefore, understanding the fundamental relationships between the components of photosensitive compositions, including the initiator, monomer/oligomer and additives, is crucial to the applicational success of bioprinting. Hence, this paper investigates the effect of a non-reactive additive to the bioresin on the photopolymerization process both in situ and in 3D-VAT printing. The following components were selected as the model system for the study: poly(ethylene glycol) diacrylate (PEGDA), lithium phenyl-2,4,6-trimethylbenzoylphosphinate (TPO-Li), and as an unreactive ingredient – water, in varying amounts. This paper presents a comprehensive research procedure using different techniques: real-time FTIR, photo-DSC and photo-rheology, to precisely quantify the relationship: kinetic of the photopolymerization process/shrinkage of the material vs the amount of non-reactive additive. The possibility of using the investigated bioresins to create three-dimensional materials was also studied. The materials, obtained by 3D-VAT printing using DLP technology, were compared in terms of the achieved optical resolution and polymer shrinkage.

Composite resins for 3D printing of corundum and corundum-kaolin based monoliths for catalytic applications

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 μm. 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 for the monolithic catalyst the yield of C2–C3 hydrocarbons is slightly lower (1–2%) but at a 3–4 times lower pressure drop.

Preparation and properties of 0.79ZnAl2O4-0.21TiO2 microwave dielectric ceramics via digital light processing

0.79ZnAl 2 O 4 -0.21TiO 2 microwave dielectric ceramics are ideal materials for preparing 5 G lens antennas. However, conventional processing methods are difficult to meet the requirements of microwave devices for high precision and designed complicated structures. Additive manufacturing technologies provide opportunities for the fabrication of these devices. Herein, we fabricated 0.79ZnAl 2 O 4 -0.21TiO 2 ceramics by digital light processing (DLP). The slurry with 2 wt% dispersant content showed favorable dispersion effect and stability. The optimal penetration depth of 44.64 µm and critical energy dose of 3.04 mJ/cm 2 were obtained. After sintering , the 0.79ZnAl 2 O 4 -0.21TiO 2 ceramic only kept ZnAl 2 O 4 phase and TiO 2 phase. The relative density could reach 95.29%, which is comparable to that of dry-pressed sample. With the increase of sintering temperature , dielectric constant ( ε r ) and quality factor ( Q×f ) of 0.79ZnAl 2 O 4 -0.21TiO 2 ceramic increased first and then decreased. The sintered ceramic at 1550 °C exhibited excellent microwave dielectric properties ( ε r = 11.55, Q×f = 62,266 GHz, τ f = −0.64 ppm/°C). The results indicate that DLP is a promising technology to fabricate high-performance microwave dielectric ceramics with complex structures. • High-performance 0.79ZnAl 2 O 4 -0.21TiO 2 ceramics were fabricated by DLP technology. • The sintered ceramic only kept ZnAl 2 O 4 spinel phase and TiO 2 rutile phase. • The relative density (95.29%) could be comparable to that of dry-pressed sample. • The ceramic showed excellent microwave dielectric property ( ε r = 11.55, Q×f = 62,266 GHz).

Stereolithography of 3D Sustainable Metal Electrodes towards High‐Performance Nickel Iron Battery

AbstractThe present‐day ubiquity of smart devices used under extreme conditions demands robust and more sustainable energy storage. Therefore, lightweight electrodes with both excellent electrochemical and mechanical performance to meet these needs are of great importance. Moreover, the recycling of current energy storage devices poses significant environmental concerns, a particularly daunting prospect given the increasing waste volume of metal‐based electrodes. To that end, these challenges of performance and sustainability are addressed by leveraging accessible digital light processing (DLP) technology and tailored post‐process heat treatment to fabricate a metal‐based 3D substrate with ultrahigh precision and hierarchical porosity. Here, a 4‐mm‐thickness metal‐based electrode with NiCo2S4 loading of 18.38 mg cm–2 achieves a high areal capacity of 7.327 mA h cm–2 at 44.85 mA cm–2, providing a promising way to fabricate high‐performance thick electrodes. Most importantly, these electrodes can be fabricated from recyclable metal salt feedstock. The geometric freedom offered by 3D printing supplemented by finite element analyses allows for optimized complex structures to be fabricated. Through rational design realized by 3D printing, a desirable compromise between building density, mechanical properties, electrochemical performances, and environment‐friendly processing cycle can be arrived upon.

Marginal and internal fit and fracture resistance of three-unit provisional restorations fabricated by additive, subtractive, and conventional methods.

To compare the marginal and internal fit and fracture resistance of three-unit provisional fixed dental prostheses (FDPs) fabricated by additive, subtractive, and conventional methods. Eighty 3-unit FDPs were fabricated on metal dies of the maxillary right second premolar and second molar by four different techniques (n = 20): The direct method by using autopolymerizing polymethyl methacrylate (PMMA), indirect method by the compression molding technique, subtractive manufacturing by using PMMA blocks, and additive manufacturing by using digital light processing technology. The adaptation of restorations at the marginal, axial, cuspal, and fossa areas was assessed by using the silicone replica technique. After thermocycling and cyclic loading, the fracture resistance was measured by a universal testing machine. Data were analyzed by atwo-wayanalysis of variance (ANOVA), ANOVA, and Tukey test (α = .05). The mean gap measured in the additive group was lower than that in all other groups at all points (p < .05); however, the difference in the marginal gap with the subtractive group was not significant (p = .995). The mean marginal and axial gaps in the subtractive group were significantly lower than the corresponding values in both conventional groups (p < .05). A significant difference existed between all groups regarding the mean cuspal and fossa gaps (p < .05). The mean fracture resistance of the additive group was significantly higher than that of indirect (p = .018) and direct (p < .001) groups, and the fracture resistance of the subtractive group was significantly higher than that of the direct group (p = .020). The digitally fabricated provisional FDPs showed superior marginal and internal fit and higher fracture resistance than the conventionally fabricated FDPs. Between the digital methods, the additive technique yielded superior internal fit.

Numerical Simulation of Sintering of DLP Printed Alumina Ceramics

Digital Light Processing (DLP) technology exhibits the capability of producing components with complex structures for a variety of technical applications. Postprocessing of additively printed ceramic components has been shown to be an important step in determining the final product resolution and mechanical qualities, particularly with regard to distortions and resultant density. The goal of this research is to study the sintering process parameters to create a nearly fully dense, defect-free, ceramic component. A high-solid-loading alumina slurry with suitable rheological and photopolymerisable characteristics for DLP was created. TGA/DSC analysis was used to estimate thermal debinding parameters. The sintering process of the debound parts was studied by employing a numerical model based on thermo-viscoelasticity theory to describe the sintering process. The validated Finite Element Modelling (FEM) code was capable of predicting shrinkage and relative density changes during the sintering cycle, as well as providing meaningful information on the final shape. Archimedes’ principle and scanning electron microscope (SEM) were used to characterise the sintered parts and validate the numerical model. Samples with high relative density (&gt;98.5%) were produced and numerical data showed close matches for predicted shrinkages and relative densities, with less than 2% mismatch between experimental results and simulations. The current model may allow to effectively predict the properties of alumina ceramics produced via DLP and tailor them for specific applications.

Digital light processing (DLP) of nano biphasic calcium phosphate bioceramic for making bone tissue engineering scaffolds

Nano-sized ceramic particles are beneficial for the properties of 3D printed structures via digital light processing (DLP). However, achieving optimal conditions for the preparation and processing of ceramic nanoparticle-based slurry is a significant challenge. In this work, a stable and well dispersed slurry with nano-sized biphasic calcium phosphate (BCP) powders was developed and porous BCP bioceramic scaffolds with good bioactivity were accurately fabricated via the DLP additive manufacturing technology. Effects of dispersant, photoinitiator and solid loading on rheological properties and curing abilities of BCP slurries were systematically studied. The slurry having 65 wt % of nano-sized BCP powders showed a relatively low viscosity of 400 mPa s at the 50 s−1 shear rate. It was found that the optimal photoinitiator concentration was tightly associated with the energy dosage in DLP. Furthermore, the effects of sintering temperature (1100 °C, 1200 °C and 1300 °C) on the surface morphology, shrinkage, phase constitution, hardness, compressive properties, and in vitro biological performance of DLP-formed bioceramics were comprehensively investigated. The results showed that DLP-formed BCP ceramics sintered at 1300 °C had the best mechanical properties, in vitro cytocompatibility, and homogeneous bone-like apatite formation ability. Finally, DLP-formed 3D scaffolds with different pore sizes ranging from 300 μm to 1 mm were successfully fabricated, which exhibited high fidelity and accuracy. The current study has demonstrated the great potential of using DLP technology to construct functional complex BCP bioceramic scaffolds for bone tissue regeneration.

Fabrication of a zirconia/calcium silicate composite scaffold based on digital light processing

Zirconia (ZrO2) and calcium silicate (CS) are widely used in bone repair. Zirconia has excellent mechanical properties, while calcium silicate has exceptional biological activity. A porous ZrO2/CS composite ceramic scaffold was formed by digital light processing (DLP) technology in this study. The microstructure analysis demonstrated that CS was embedded between ZrO2 particles. Mechanical tests showed that interconnected CS particles could improve mechanical properties, while discrete CS particles led to a decrease in that. Cell experiments showed that adding CS to ZrO2 had a positive effect on cell proliferation and differentiation. In vitro degradation test showed that the weight loss of scaffolds in four weeks increased form −0.63%–1.42% with the increase of CS content. Moreover, the degradation of scaffold promoted the deposition of apatite, which was beneficial to the integration of the scaffold with living bone. In conclusion, the ZrO2/CS composite scaffold had better biocompatibility compared with the ZrO2 scaffold, which showed a potential solution for 3D printing bone repair scaffolds.

3D printing of metallic structures using dopamine-integrated photopolymer

After 3D printing technology has been advancing for several years, it still faces a huge challenge to fabricate 3D metal structures with high-resolution. In this study, a facile strategy of making high-resolution metallic structures based on the bioinspired 3D printing method was proposed. A bioinspired initiator, dopamine, was mixed into a 3D printing photopolymer, which could be conducive to fabricating metallic structures after direct surface-initiated electroless plating (ELP). Because of the intrinsic high resolution of the structures printed with the digital light processing (DLP) technology, complex objects with a feature resolution on the order of 137 μm were fabricated. Moreover, Cu- and Ni-parts of complex structures with a high resolution were demonstrated. By combining the advantages of 3D printing in structure design with those of surface modification assisted by catechol groups, the proposed method was confirmed as a cost-effective method to significantly enhance the capability of 3D printing, and it could endow the 3D printing technology with more practical applications in electronics, acoustic absorption, catalyst supports and other fields.

Highly stretchable dual‐cure photosensitive resin for digital light processing printing

AbstractThe two‐stage curing approach is one of the promising strategies to achieve the 3D printing of high‐performance elastomers. Herein, a novel resin formulation that is composed of a photocurable acrylic resin and a mixture of thermocurable isocyanate oligomer/diamine is evaluated by digital light processing technology. Such resin possesses a satisfying viscosity for printing, especially at ambient temperature. For first curing stage, that is, photocurable stage, precisely architectural components with the required shape can be fabricated by a free‐radical photopolymerization. Methyl ethyl ketone oxime that serves as a blocking agent, was employed to ensure the stability of isocyanate resin during this stage. Consecutively, a thermally activated deblocking process is carried out and accompanied by isocyanate/diamine copolymerization, which is the second curing stage. An interpenetrating polymer networks structure in designing resin (25 wt% photocurable resin and 75 wt% thermocurable resin) was formed after thermal curing, which is of significance for achieving excellently comprehensive mechanical properties. Contributed by special structures, it is capable of reaching a 4.67 MPa of tensile strength at 100% strain, while yielding favorable tensile strength of 7.51 MPa as well a maximum elongation at break of 745.3%, which is nearly identical to the initial mechanical performances of pure polyurethane elastomer.

Photocurable epsilon-poly-l-lysine for digital light processing 3D printing

In this work, we provided a photocurable bioink composed of modified epsilon-poly-l-lysine (EPL-MA) for digital light processing (DLP). The EPL-MA was facilely synthesized by grafting with the glycidyl methacrylate (GMA) via a nucleophilic amination ring-opening reaction and forming linkages between EPL and GMA. The photocuring efficiency of the optimized EPL-MA hydrogel could be modulated. Through the DLP technology, highly complex organ model structures can be built by using this EPL-MA bioink with excellent reliable biocompatibility. It indicates that this photocurable EPL-MA is promising bioink used for DLP 3D printing and may has potential application in tissue engineering.

Crown fit and dimensional accuracy of zirconia fixed crowns based on the digital light processing technology

Zirconia is extensively used for manufacturing dental prostheses because of its superior mechanical properties. The idea of using 3D printing to manufacture zirconia dental prostheses has gradually become popular, but printing accurate shapes and obtaining excellent dimensional accuracy still remain challenging. In this study, the optimal curing parameters and shrinkage ratios of zirconia slurry were investigated using a multi-angle model and a standard fixed crown model. Then the dimensional accuracy and crown fit were investigated, and the fixed crown and fixed bridge were fabricated by using digital light processing (DLP) technology. Further, the dimensional accuracy and crown fit were investigated. The results showed that the optimal curing parameters and enlargement factors for zirconia fixed crown printing were 80 PWM (light source power), 2s (curing time) and 1.400, 1.400, 1.500 (in X, Y, Z directions), respectively. The internal fit was 239.3 ± 7.9 μm, which met the clinical criteria (≤300 μm), whereas the marginal fit was 128.1 ± 7.1 μm, which was extremely close to the clinical criteria (≤120 μm). For dimensional accuracy, the standard error of sintered fixed crown was 0.14 ± 0.06 mm, and the boundary dimensional accuracy and anatomical landmark points’ dimensional accuracy were also investigated. In addition, the density of sintered zirconia was 6.01 ± 0.02 g/cm 3. From the results of this study, it could be found that the crown fit of zirconia fixed crowns printed using the DLP technique could be close to clinical standards, although there is still a gap with the zirconia fixed crowns from the milling technique. In addition incomplete removal of the support structures have a negative impact on dimensional accuracy, hence it is necessary to further explore the optimization strategies of the support structures for improving the dimensional accuracy of fixed crowns printed by DLP.

Microwave dielectric properties of (0.75ZnAl2O4–0.25TiO2)–MgTiO3 ceramics prepared using digital light processing technology

AbstractZTM ceramics comprising of 0.75ZnAl2O4–0.25TiO2 and MgTiO3 at a ratio of 90:10 wt.% are widely used in the field of communication as filters and resonators owing to their excellent microwave dielectric properties. However, the development of such dielectrics with complex structures, as required by microwave devices, is difficult using traditional fabrication methods. In this study, ZTM microwave dielectric ceramics were prepared using the digital light processing (DLP) technology. The influence of the sintering temperature on the phase composition, microstructure, and microwave dielectric properties of ZTM ceramics was investigated. Results showed that with an increase in the sintering temperature, the dielectric constant (εr) and quality factor (Q × f) of ZTM ceramics initially increased owing to the increase in the density and diffusion of ions. However, when the sintering temperature was excessively high, the abnormal growth of crystal grains and micropores led to a decrease in εr and Q × f. The ZTM ceramics sintered at 1450°C exhibited the optimum microwave dielectric properties (εr = 12.99, Q × f = 69 245 GHz, τf = −9.50 ppm/°C) owing to the uniform microstructure and a high relative density of 95.02%. These results indicate that DLP is a promising method for preparing high‐performance microwave dielectric ceramics with complex structures.

Fabrication and biological evaluation of 3D-printed calcium phosphate ceramic scaffolds with distinct macroporous geometries through digital light processing technology.

Digital light processing (DLP)-based 3D printing technique holds promise in fabricating scaffolds with high precision. Here raw calcium phosphate (CaP) powders were modified by 5.5% monoalcohol ethoxylate phosphate (MAEP) to ensure high solid loading and low viscosity. The rheological tests found that photocurable slurries composed of 50 wt% modified CaP powders and 2 wt% toners were suitable for DLP printing. Based on geometric models designed by computer-aided design (CAD) system, three printed CaP ceramics with distinct macroporous structures were prepared, including simple cube, octet-truss and inverse face-centered cube (fcc), which presented the similar phase composition and microstructure, but the different macropore geometries. Inverse fcc group showed the highest porosity and compressive strength. The in vitro and in vivo biological evaluations were performed to compare the bioactivity of three printed CaP ceramics, and the traditional foamed ceramic was used as control. It suggested that all CaP ceramics exhibited good biocompatibility, as evidence by an even bone-like apatite layer formation on the surface, and the good cell proliferation and spreading. A mouse intramuscular implantation model found that all of CaP ceramics could induce ectopic bone formation, and foam group had the strongest osteoinduction, followed by inverse fcc, while cube and octet-truss had the weakest one. It indicated that macropore geometry was of great importance to affect the osteoinductivity of scaffolds, and spherical, concave macropores facilitated osteogenesis. These findings provide a strategy to design and fabricate high-performance orthopedic grafts with proper pore geometry and desired biological performance via DLP-based 3D printing technique.

The Influence of Microstructure on the Flexural Properties of 3D Printed Zirconia Part via Digital Light Processing Technology.

In recent years, additive manufacturing of ceramics is becoming of increasing interest due to the possibility of the fabrication of complex shaped parts. However, the fabrication of a fully dense bulk ceramic part without cracks and defects is still challenging. In the presented work, the digital light processing method was introduced for fabricating zirconia parts. The flexural properties of the printed zirconia were systematically investigated via a three-point bending test with the digital image correlation method, scanning electron microscopy observation and fractography analysis. Due to the anisotropy of the sample, the bending deformation behaviors of the zirconia samples in the parallel and vertical printing directions were significantly different. The flexural strength and the related elastic modulus of the samples under vertical loading were higher than that of the parallel loading, as the in-plane strength is higher than that of the interlayer strength. The maximum horizontal strain always appeared at the bottom center before the failure for the parallel loading case; while the maximum horizontal strain for the vertical loading moved upward from the bottom center to the top center. There was a clear dividing line between the minimum perpendicular strain and the maximum perpendicular strain of the samples under parallel loading; however, under vertical loading, the perpendicular strain declined from the bottom to the top along the crack path. The surrounding dense part of the sintered sample (a few hundred microns) was mainly composed of large and straight cracks between printing layers, whereas the interior contained numerous small winding cracks. The intense cracks inside the sample led to a low flexural property compared to other well-prepared zirconia samples, which the inadequate additive formulations would be the main reason for the generation of cracks. A better understanding of the additive formulation (particularly the dispersant) and the debinding-sintering process are necessary for future improvement.

Three‐dimensional complex construct fabrication of illite by digital light processing‐based additive manufacturing technology

AbstractIllite is a group of clay minerals that are expected to be widely used in catalyst fabrication, radioactive element adsorption, and so forth, due to its excellent adsorption properties. However, the shape control limitation of the illite product should be overcome to maximize its utilization and properties. We herein propose additive manufacturing (AM) as one of the best solutions to solve this structural drawback. Digital light processing (DLP) technology with the film‐type of the material supplying system was adapted instead of the general vat‐type DLP system to increase illite printability. The photo‐curability and printability of illite‐contained photocurable suspension were optimized. The color effect due to different ferric oxide content in yellow‐ and white‐illite which influence the photopolymerization process also adjusted thoroughly. White illite showed better photo‐curability and could be increased solid loading than yellow illite. The defect‐free illite products with three‐dimensional complex structures, which cannot be produced by typical ceramic processes, were obtained by DLP technology for both yellow‐ and white‐illite after sintering at 1100°C. The overcoming of shape control limitation of illites by ceramic AM proved in this study has excellent potential for expanding illite utilities in various applications.

Effects of debinding condition on microstructure and densification of alumina ceramics shaped with photopolymerization-based additive manufacturing technology

Alumina green bodies shaped with digital light processing (DLP) technology were debinded in four atmospheres, including air, argon (Ar), mixture of 95% argon and 5% hydrogen (95% Ar +5% H2) and vacuum, at different heating rates (0.5 °C/min, 1 °C/min and 3 °C/min), followed by sintering in air at 1650 °C for 3 h. The effects of debinding atmosphere and heating rate on microstructure and densification of the brown bodies and sintered bodies were evaluated via morphology characterization, X-ray computed tomography (CT) reconstructions and other tests. Focusing on the quantitative analysis of the geometric characteristics and distribution of defects in the brown bodies and sintered bodies, it is found that the type (holes, cracks and delamination), content and volume distribution of defects during the debinding in aerobic and anaerobic environments are different. Our study indicates that low-rate vacuum debinding should be adopted as a promising debinding approach for ceramics shaped with photopolymerization-based additive manufacturing technology.