Effective Spiral Laser Path for Minimizing Local Heating and Anisotropic Microstructures in Powder Bed Fusion Additive Manufacturing.

Heat accumulation due to repetitive simple laser processing paths during building up a three-dimensional structure is a well-known issue that needs to be settled to reduce the excessively high residual stress and thermal deformation in a powder bed fusion (PBF) additive manufacturing process. Because of the dependency of laser path on the thermal dispersion, it is essential to analyze the heat accumulation phenomenon during laser processing. A computational fluid dynamics (CFD) analysis based on the volume of fraction method is used to optimize the laser path for minimizing the local heating up in the PBF process.

Meta-structure of amorphous-inspired 65.1Co28.2Cr5.3Mo lattices augmented by artificial intelligence.

Unlabelled: A hatching-distance-controlled lattice of 65.1Co28.2Cr5.

Crack Control in Additive Manufacturing by Leveraging Process Parameters and Lattice Design.

This study investigates the design of additive manufacturing for controlled crack propagation using process parameters and lattice structures. We examine two lattice types-octet-truss (OT) and diamond (DM)-fabricated via powder bed fusion with Ti-6Al-4V. Lattice structures are designed with varying densities (10%, 30%, and 50%) and process using two different laser energies.

Enhanced Energy Absorption of Additive-Manufactured Ti-6Al-4V Parts via Hybrid Lattice Structures.

In this study, we present the energy absorption capabilities achieved through the application of hybrid lattice structures, emphasizing their potential across various industrial sectors. Utilizing Ti-6Al-4V and powder bed fusion (PBF) techniques, we fabricated distinct octet truss, diamond, and diagonal lattice structures, tailoring each to specific densities such as 10, 30, and 50%. Furthermore, through the innovative layering of diverse lattice types, we introduced hybrid lattice structures that effectively overcome the inherent energy absorption limitations of single-lattice structures.

In-situ ionic crosslinking of 3D bioprinted cell-hydrogel constructs for mechanical reinforcement and improved cell growth.

Hydrogels are commonly used in 3D bioprinting technology owing to their ability to encapsulate living cells. However, their inherent delicate properties limit their applicability in the fabrication of mechanically reliable tissue engineering constructs. Herein, we propose a novel reinvented layering integration method for the functional enhancement of 3D cell-hydrogel bioprinting.

The effect of 3-D printed polylactic acid scaffold with and without hyaluronic acid on bone regeneration.

Background: Three- dimensional (3D) technology has been suggested to overcome several limitations in guided bone regeneration (GBR) procedures because 3D-printed scaffolds can be easily molded to patient-specific bone defect site. This study aimed to investigate the effect of 3-D printed polylactic acid (PLA) scaffolds with or without hyaluronic acid (HA) in a rabbit calvaria model.

Methods: A calvaria defect with a diameter of 15 mm was created in 30 New Zealand white rabbits.

Additive manufacturing of the core template for the fabrication of an artificial blood vessel: the relationship between the extruded deposition diameter and the filament/nozzle transition ratio.

An artificial blood vessel with a tubular structure was additively manufactured via fused deposition modeling (FDM) starting from a single strand of polyvinyl alcohol (PVA) filament coated with a specific thickness of biocompatible polydimethylsiloxane (PDMS), followed by removal of the inner core via hydrogen peroxide leaching under sonication. In particular, we examined the relationship between the extruded deposition diameter and the filament migration speed/nozzle control speed (referred to as the filament/nozzle transition ratio), which is almost independent of the extruded deposition flow rate due to the weak die-swelling and memory effects of the extruded PVA arising from its intrinsically low viscoelasticity. The chemical stability of the PDMS during sonication in the hydrogen peroxide solution was then determined by spectroscopic techniques.

Enhanced bioactivity of titanium-coated polyetheretherketone implants created by a high-temperature 3D printing process.

Polyetheretherketone (PEEK), one of the potential alternatives to metallic materials for implants, necessarily involves high temperature process conditions to be three-dimensionally (3D) printed. We developed a 3D printing setup equipped with thermally stabilized modules of the printing nozzle and building chamber, by which the PEEK implants could be successfully manufactured. Under optimized printing conditions, the maximal mechanical strength of the 3D printed sample attained over 80% of the original bulk property of PEEK.

Fine Microstructured In-Sn-Bi Solder for Adhesion on a Flexible PET Substrate: Its Effect on Superplasticity and Toughness.

A novel In-Sn-Bi solder with a low electrical resistivity of 14.3 × 10 Ω cm and a melting temperature of 99.3 °C was produced for use in adhesive joining on a flexible poly(ethylene terephthalate) substrate.

Fabrication of 3D freeform porous tubular constructs with mechanical flexibility mimicking that of soft vascular tissue.

Three-dimensional (3D) printing, with its capability for producing arbitrary shapes, has been extensively studied for tissue engineering applications. However, clinical applications, especially for soft tissues, have been limited due to mechanical mismatch between the 3D-printed artificial tissues and the native tissues. Here, we suggest an integrative method of 3D printing, dip coating, and salt leaching for the fabrication of soft 3D freeform porous tubes, which are expected to be applied to the engineering of vascular tissues.

Characteristics of Carrier Collection of Nanopillar-Patterned Silicon Solar Cells.

Nanopillar-patterned Si solar cells were investigated. Ag nanoparticles were coated on a polished Si substrate as an etching mask. Reactive ion etching caused Si nanopillars to replicate in a reverse fashion on the Ag nanoparticles over a large area.

Optimized film processing of nanosilver colloids for photoluminescence enhancement.

Recently, various research strategies have been employed to improve light extraction efficiency in organic LEDs, including the recent development of localized surface plasmon resonance (LSPR), as well as the more widely-known application of a photonic crystal layer. Here, we report on the development of a process method for forming a two-dimensional nanosilver patterned array to achieve LSPR-coupled light-emission efficiency enhancement. The process scheme involves the spin-coating of nanosilver colloidal ink onto a glass substrate, followed by optimized thermal annealing to create an array of isolated nanosilver islands.

Nanosilver Colloids-Filled Photonic Crystal Arrays for Photoluminescence Enhancement.

For the improved surface plasmon-coupled photoluminescence emission, a more accessible fabrication method of a controlled nanosilver pattern array was developed by effectively filling the predefined hole array with nanosilver colloid in a UV-curable resin via direct nanoimprinting. When applied to a glass substrate for light emittance with an oxide spacer layer on top of the nanosilver pattern, hybrid emission enhancements were produced from both the localized surface plasmon resonance-coupled emission enhancement and the guided light extraction from the photonic crystal array. When CdSe/ZnS nanocrystal quantum dots were deposited as an active emitter, a total photoluminescence intensity improvement of 84% was observed.

An Antireflective Nanostructure Array Fabricated by Nanosilver Colloidal Lithography on a Silicon Substrate.

An alternative method is presented for fabricating an antireflective nanostructure array using nanosilver colloidal lithography. Spin coating was used to produce the multilayered silver nanoparticles, which grew by self-assembly and were transformed into randomly distributed nanosilver islands through the thermodynamic action of dewetting and Oswald ripening. The average size and coverage rate of the islands increased with concentration in the range of 50-90 nm and 40-65%, respectively.