On Laminated Object Manufactured FDM-Printed ABS/TPU Multimaterial Specimens: An Insight into Mechanical and Morphological Characteristics

3D printing chronicles in medical devices and pharmaceuticals: tracing the evolution and historical milestones

The objective of this study is to collect the significant advancements of 3D printed medical devices in the biomedical area in recent years. Especially related to a range of diseases and the polymers employed in drug administration. To address the existing limitations and constraints associated with the method used for producing 3D printed medical devices, in order to optimize their suitability for degradation. The compilation and use of research papers, reports, and patents that are relevant to the key keywords are employed to improve comprehension. According to this thorough investigation, it can be inferred that the 3D Printing method, specifically Fuse Deposition Modeling (FDM), is the most suitable and convenient approach for preparing medical devices. This study provides an analysis and summary of the development trend of 3D printed implantable medical devices, focusing on the production process, materials specially the polymers, and typical items associated with 3D printing technology. This study offers a comprehensive examination of nanocarrier research and its corresponding discoveries. The FDM method, which is already facing significant challenges in terms of achieving optimal performance and cost reduction, will experience remarkable advantages from this highly valuable technology. The objective of this analysis is to showcase the efficacy and limitations of 3D-printing applications in medical devices through thorough research, highlighting the significant technological advancements it offers. This article provides a comprehensive overview of the most recent research and discoveries on 3D-printed medical devices, offering significant insights into their study.

Acrylonitrile Butadiene Styrene/Thermoplastic Polyurethane Blends for Material Extrusion Three-Dimensional Printing: Effects of Blend Composition on Printability and Properties

Blend filaments of acrylonitrile butadiene styrene (ABS) and thermoplastic polyurethane (TPU) were prepared at different weight ratios, i.e., 100:0, 70:30, 50:50, 30:70, and 0:100, for FDM printing; the prepared filaments, with an average diameter of 2.77 ± 0.19 mm, were encoded as A100, A70T30, A50T50, A30T70, and T100, respectively. The properties and printability of the filaments were thoroughly investigated. The blend composition, as well as the printing parameters, were optimized to obtain the FDM-printed objects with a well-defined surface structure and minimized warpages. The glass transition temperatures of ABS and TPU in the blends were not much altered from those of the parent filaments, whereas the thermal degradation characteristics of the blend filaments still fell between those of the neat filaments. The fractured surfaces of the filaments, observed by SEM, appeared smoother when higher amounts of TPU integrated; the smoothest surface of the ABS-based filament was found in A30T70, indicating the well-compatible blend characteristic. This was also confirmed by its rheological behavior examined by a parallel plate rheometer at 225 °C. Not only was the printability of the filaments improved, but also the warpages of the 3D-printed specimens were decreased when increasing amount of TPU was incorporated into the filaments. Among the printed objects, the A30T70 specimen exhibited the evenest surface morphology with the lowest surface roughness value of 32.9 ± 13.2 nm and the most uniform and consistent linear printing structure when being fabricated at the nozzle temperature of 225 °C and the printing bed temperature of 60 °C. However, the incorporation of TPU into the filaments markedly cut down both strength and modulus values of the fabricated materials up to about half but assisted the printed articles to absorb more energy, demonstrating that this polymer served as a good and effective toughener for ABS.

Study on CNT/TPU cube under the 3D printing conditions of infill patterns and density

In this study, to develop soft pressure sensor applicable to wearable robots using stretchable polymers and conductive fillers, 3.25 wt% carbon nanotubes/thermoplastic polyurethane filament with shore 94 A were manufactured. Three infill densities (20%, 50%, and 80%) and patterns (zigzag (ZG), triangle (TR), honeycomb (HN)) were applied to print cubes via fused filament fabrication 3D printing. Most suitable infill conditions were confirmed based on the slicing images, morphologies, compressive properties, electrical properties, and electrical heating properties. For each infill pattern, ZG and TR divided the layers into lines and figures, and the layers were stacked by rotation. For HN, the same layers were stacked in a hexagonal pattern. Consequently, TR divided layer in various directions, showed the strongest compressive properties with toughness 1.99 J for of infill density 80%. Especially, the HN became tougher with increased infill density. Also, the HN laminated with the same layer showed excellent electrical properties, with results greater than 14.7 mA. The electrical heating properties confirmed that ZG and HN had the high layer density, which exhibited excellent heating characteristics. Therefore, it was confirmed that performance varies depending on the 3D printing direction, and it was confirmed that HN is suitable for manufacturing soft sensors.

Multi-objective numerical optimization of 3D-printed polylactic acid bio-metamaterial based on topology, filling pattern, and infill density via fatigue lifetime and mass

Infill parameters are significant with regard to the overall cost and saving material while printing a 3D model. When it comes to printing time, we can decrease the printing time by altering the infill, which also reduces the total process extent. Choosing the right filling parameters affects the strength of the printed model. In this research, the effect of filling density and infill pattern on the fatigue lifetime of cylindrical polylactic acid (PLA) samples was investigated with finite element modeling and analysis. This causes the lattice structure to be considered macro-scale porosity in the additive manufacturing process. Due to the need for multi-objective optimization of several functions at the same time and the inevitable sacrifice of other objectives, the decision was to obtain a set of compromise solutions according to the Pareto-optimal solution technique or the Pareto non-inferior solution approach. As a result, a horizontally printed rectangular pattern with 60% filling was preferred over the four patterns including honeycomb, triangular, regular octagon, and irregular octagon by considering the sum of mass changes and fatigue lifetime changes, and distance from the optimal point, which is the lightest structure with the maximum fatigue lifetime as an objective function with an emphasis on mass as an important parameter in designing scaffolds and biomedical structures. A new structure was also proposed by performing a structural optimization process using computer-aided design tools and also, computer-aided engineering software by Dassault systems. Finally, the selected samples were printed and their 3D printing quality was investigated using field emission scanning electron microscopy inspection.

Koloor SS, Kumar D, Yahya MY, Mago J. On Comparison of Heat Treated and Non-Heat-Treated LOM Manufactured Sample for Poly(lactic)acid: Mechanical and Morphological View Point

This work reports the comparison of heat-treated and non-heat-treated laminated object-manufactured (LOM) 3D-printed specimens from mechanical and morphological viewpoints. The study suggests that heat treatment of the FDM-printed specimen may have a significant impact on the material characteristics of the polymer. The work has been performed at two stages for the characterization of (a) non-heat-treated samples and (b) heat-treated samples. The results for stage 1 (non-heat-treated samples) suggest that the infill density: 70%, infill pattern: honeycomb, and six number of discs in a single LOM-manufactured sample is the optimized condition with a compression strength of 42.47 MPa. The heat treatment analysis at stage 2 suggests that a high temperature: 65 °C, low time interval: 10 min, works equally well as the low temperature: 55 °C, high time interval: 30 min. The post-heat treatment near Tg (65 °C) for a time interval of 10 min improved the compressive strength by 105.42%.