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The development of photosensitive ceramic slurries for vat photopolymerization (stereolithography or digital light processing) has received much effort in recent years. However, many of these ceramic suspensions have high viscosity and they are suitable for use only on equipment, specialized in ceramic additive manufacturing. In this work, ceramic manufacturing using photocurable slurries was tested in a low-cost vat photopolymerization printer and in silicone moulds for UV-casting replication, with the latter approach still scarcely explored in the literature. Both processes were able to produce ceramic parts. The UV-casting replication was able to work with more viscous photocurable ceramic slurries and proved more suitable for the manufacturing of ceramic parts with larger cross-sections, providing pieces with improved flexural strength to those produced by additive manufacturing. This work presents the possibility of UV-casting photosensitive slurries to manufacture ceramics, an approach that could be easily adopted without high equipment costs.

Lean is applied in automobile companies to reduce lead time and waste through value stream mapping. Industry 4.0 is a process of industrial systems revolution in companies driven by digitalization and data-oriented techniques. The combination of both is called Lean 4.0. In this sense, the purpose of this paper is to attend Ultra-Light Steel Auto-body (ULSAB) automotive requirements through Lean 4.0 framework applied in the fabrication of B-pillar by hot stamping. Optimization algorithms are important to simulate different scenarios and interact with these processes. The proposal was developed in the case study by assessments based on semi-structured questionnaires, analysis of records and documents. The findings showed overall equipment effectiveness (OEE) was increased by 41.5%. The contribution of this work was to meet ULSAB automotive requirements for hot stamping process by reducing vehicle weight while increasing structural strength. [ABSTRACT FROM AUTHOR]

This study aimed to produce and characterize the microstructure and mechanical properties of dense polycrystalline bovine hydroxyapatite (DPBHA) bioceramics with 5% and 8% of TiO2 nanoparticles after final synthetization for future use in dental implants. Structural characterization was obtained from analyzes by Fourier transform infrared spectroscopy, X‐ray diffraction, scanning electron microscope, energy dispersive spectroscopy, and relative density and apparent porosity. The mechanical characterization was performed by measuring the fracture toughness after three‐point flexural strength (FS) test. The microstructural characterization results showed no secondary phase formation and nonhomogeneous nanoparticle dispersion in HA matrix. DPBHA/Np8% (2.9 ± 0.09 g/cm3) exhibited significantly greater density than DPBHA (2.7 ± 0.03 g/cm3) (p = 0.011) and DPBHA/Np5% (2.7 ± 0.05 g/cm3) (p = 0.041). DPBHA (0.9%) had the smallest porosity followed by DPBHA/Np8% (3.4%). DPBHA/Np5% (4.5%) exhibited the greatest proportion of pores. Pure HA (51.7 ± 10.3 MPa) and DPBHA/Np8% (47.4 ± 6.4 MPa) had significant greater FS (p < 0.001) than DPBHA/Np5% (28.8 ± 3.1 MPa). DPBHA (0.43 ± 0.01 MPa m1/2) and DPBHA/Np8% (0.40 ± 0.06 MPa m1/2) presented greater KIc than DPBHA/Np5% (0.23 ± 0.02 MPa m1/2) (p < 0.003; p < 0.007). In conclusion, 8% TiO2 nanoparticle addition to this synthesis would be a promising HA blend, as mechanical properties were similar, and the relative density/apparent porosity showed superior results than those of the DPBHA. [ABSTRACT FROM AUTHOR]

Objectives: A bovine dense hydroxyapatite ceramic (HA) was produced as new biomaterial, however, the production of a material with consistently high flexural strength remains challenging. The objective of this study was to evaluate the effects of ZnO nanoparticles, TiO 2 nanoparticles, and TiO 2 nanotubes (1%, 2%, and 5% by weight) on the microstructure and flexural strength of a bovine dense hydroxyapatite ceramic (HA)., Methods: Discs (Ø=12.5mm; thickness=1.3mm) were prepared and subjected to X-ray diffraction (XRD), and observation with a field emission scanning electron microscope (FE-SEM), biaxial flexural strength (BFS) testing, and Vickers hardness (VH) testing. The BFS and VH data were subjected to ANOVA and Tukey post-hoc tests (α=0.05) and Weibull analysis., Results: The XRD showed that the addition of nanomaterials caused the formation of a secondary phase when 5% of the ZnO nanoparticles was used, or when all percentages of the TiO 2 nanoparticles/nanotubes were used, and the HA crystallographic planes were maintained. Differences were not observed between the higher BFS values obtained with pure HA and those obtained with the 5% addition of TiO 2 nanoparticles. However, the results were different compared with the other groups (α=0.05). The results obtained by Weibull analysis revealed that the 1%, 2%, and 5% addition of TiO 2 nanotubes, and the 1% and 2% addition of TiO 2 nanoparticles decreased the HA characteristic strength (σ 0 ), while the Weibull modulus (m) increased when 5% of TiO 2 nanoparticles, 1% and 2% of ZnO nanoparticles, and 2% of TiO 2 nanoparticles were added, but with no statistical difference from the pure HA. The 5% addition of ZnO 2 nanoparticles decreased the σ 0 without changing m. Moreover, the 5% addition of TiO 2 nanoparticles resulted in an m closest to that of pure HA. Regarding the VH results, the blend of HA with 1% and 2% addition of TiO 2 nanoparticles exhibited the higher values, which were similar between the different addition ratios (p=0.102). Moreover, the addition of 5% TiO 2 nanoparticles resulted in higher value compared with pure HA., Significance: This study demonstrated that the HA blend with 5% of TiO 2 nanoparticles has the greatest potential as a bovine HA dense bioceramic reinforcement., (Copyright © 2019 The Academy of Dental Materials. Published by Elsevier Inc. All rights reserved.)