3D printing is a hot topic in electroanalytical chemistry, allowing the construction of custom cells and sensors at affordable prices. In this work, we describe a novel small and practical 3D-printed ...electrochemical cell. The cell's body, manufactured in ABS on a 3D printer, is composed by three parts easily screwed: solution vessel, stick and cover with two embedded 3D-pen-printed carbon black-polylactic acid (CB-PLA) electrodes (counter and pseudo-reference). The cell is compatible with any planar working electrode, in which boron-doped diamond, graphite sheet (GS) and 3D-printed CB-PLA were shown as examples. A new alternative protocol to quickly produce 3D-printed sensors using a 3D pen and other low-cost apparatus is also proposed. The voltammetric performance of each evaluated sensor was carried out in the presence of redox probe ferricyanide and paracetamol as model analyte, and the surfaces were characterized by electrochemical impedance spectroscopy and scanning electrochemical microscopy. To present an analytical application of the 3D-printed cell, low-cost flexible sensors (GS and CB-PLA) were used as integrated platforms for sampling and detection of solid drugs. As a proof-of-concept, traces of drugs with a historic of counterfeit or adulteration (sildenafil citrate, tadalafil, losartan and 17α-ethinylestradiol) were abrasively sampled over the sensor and assembled on 3D-printed cell to perform a fast voltammetric scan in the presence of only 500 μL of electrolyte. This protocol is attractive for pharmaceutical and forensic sciences as a simple preliminary screening method which could identify the presence or absence of the suspicious drug as well as impurities or adulterants. The 3D-printed cell was also used for the determination of 17α-ethinylestradiol in a contraceptive pill to demonstrate a quantitative analysis. The cell is quickly printed (90 min), cheap (US$ 0.30) and requires low electrolyte volumes (0.5–3.0 mL), being suitable to be used in several other electroanalyses, especially for on-site applications.
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•Small and practical 3D-printed cell compatible with any planar working electrode.•Combination of 3D printer and 3D pen for the manufacture of body and electrodes.•3D-printed cell requires lower sample volumes for electroanalyses (0.5–3.0 mL).•New protocol to produce quickly a set of 3D-printed sensors using only 3D pen.•Application for sampling and electroanalysis of drugs in the same flexible sensor.
Different from other 3D printing techniques such as selective laser sintering (SLS), stereolithography (SLA), three-dimensional printing (3DP), and laminated object manufacturing (LOM), the fused ...deposition modeling (FDM) technology is widely used in aerospace, automobile making, bio-medicals, smart home, stationery and training aids, and creative gifts for its easy use, simple operation, and low cost. The polylactic acid (PLA) is a material most extensively applied in FDM technology for its low melting point, non-poison, non-irritation, and sound biocompatibility. The FDM 3D-printed PLA parts are a research hotspot in the 3D printing field. This paper is intended to sum up the latest research results and achievements made in recent years in the interface bonding property, mechanical properties, and shape precision promotion of FDM 3D-printed PLA parts as well as the functional expansion of the PLA parts based on vast domestic and overseas literature. The literature research collection focuses on the following two aspects: one is the macroscopic technical research on the optimal settings of key technological parameters; the other one is the PLA modification research on improvement of cross-linking state and crystallinity of PLA molecular chains, carbon reinforced phase modification of PLA, and PLA functional compound modification. The researches in the two aspects are of importance in improving whole properties, enhancing functional applications, and expanding and enriching the applications of FDM 3D-printed PLA parts. This paper is expected to give some helps and references to the researchers who are specializing in the 3D printing field.
Thermoplastic extrusion based additive manufacturing (MEX-AM), is a very interesting fabrication method for the shaping of larger ceramic parts. Commercial filaments are currently available in the ...market, but due to the lack of information from the suppliers, it is not easy to select the suitable filament material for the 3D printing of individual ceramic objects. In this study, three commercial yttria-stabilized zirconia (YSZ) filaments provided by Fabru GmbH, SiCeram GmbH and PT+A GmbH were investigated. According to our results, it is possible to print YSZ filaments with extremely different flexibility and rheological properties. Compared to the other two filaments, the Fabru filament resulted in significantly higher flexibility, but the extrusion pressure to print it through a 0.25 mm nozzle was significantly higher at 150 °C. Interestingly, in the SiCeram filament, a grain orientation effect could be observed. Based on STA analysis it can be assumed that for the Fabru filament, the polymer which decomposes at a high temperature can already be removed by solvent debinding (SD). Finally, 70 mm tall cup structure including overhang features and different wall thicknesses was used to evaluate the printing and post-processing of YSZ filaments.
In this study, the suitability of natural rubber (NR) toughened poly(lactic acid) (PLA)-based blends were investigated for additive manufacturing applications. Filaments for fused deposition modeling ...(FDM) were prepared with an NR concentration of 0 … 20 wt% using a twin-screw extruder. Subsequently, specimens were fabricated with a desktop 3D printer machine working on FDM principles. Besides the composition of PLA/NR blends, the effect of infill orientation was also analyzed by preparing two sets of specimens: i) one set prepared with an alternating raster angle of ±45° (3DGRID) and ii) another one with a linear infill parallel to the length of the specimens (3DPAR). Quasi-static and dynamic mechanical properties, morphology and thermal characteristics of the fabricated specimens were investigated. The tensile tests revealed that the presence of NR effectively enhances the ductility of PLA filaments, however, the achieved improvement was highly dependent on the applied infill pattern. Samples prepared using the 3DPAR infill exhibited an excellent deformability when paired with NR. On the other hand, the ones fabricated with the 3DGRID technique only showed a marginal improvement in elongation. Similarly, the Charpy impact tests indicated an outstanding impact resistance of NR-toughened 3DPAR specimens, while the 3DGRID types showed little to no improvement. Scanning electron microscopic analysis revealed a weaker interlayer adhesion in the specimens containing NR, which greatly contributed to the discrepancies observed between the mechanical properties of the samples prepared with different infill. The differential scanning calorimetry revealed an almost completely amorphous structure of 3D printed PLA due to the quite rapid cooling characteristic of the FDM technique, which was not affected by the embedded NR component.
•Improvement of impact toughness of PLA in fused deposition modeling by blending it with natural rubber (0 … 20 wt%).•The effect of infill raster angle examined.•Excellent ductility was achieved, especially with an infill orientation parallel to the length of the specimens.•The interlayer adhesion weakens at high NR concentration.
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During the last decade, an innovative lab on a chip technology known as microfluidics became popular in the pharmaceutical field to produce nanomedicines in a scalable way. ...Nevertheless, the predominant barriers for new microfluidics users are access to expensive equipment and device fabrication expertise.
3D printing technology promises to be an enabling new field that helps to overcome these drawbacks expanding the realm of microfluidics. Among 3D printing techniques, fused deposition modeling allows the production of devices with relatively inexpensive materials and printers.
In this work, we developed two different microfluidic chips designed to obtain a passive micromixing by a “zigzag” bas-relief and by the presence of “split and recombine” channels. Computational fluid dynamics studies improved the evaluation of the mixing potential. A fused deposition modeling 3D printer was used to print the developed devices with polypropylene as manufacturing material. Then, two different model nanocarriers (i.e., polymeric nanoparticles and liposomes), loading cannabidiol as model drug, were formulated evaluating the influence of manufacturing parameters on the final nanocarrier characteristics with a design of experiments approach (2-level full factorial design).
Both the chips showed an effective production of nanocarriers with tunable characteristics and with an efficient drug loading.
These polypropylene-based microfluidic chips could represent an affordable and low-cost alternative to common microfluidic devices for the effective manufacturing of nanomedicines (both polymer- and lipid-based) after appropriate tuning of manufacturing parameters.
•RSM based on Q-optimal design for FDM process optimization is proposed.•Mathematical models are developed and verified with experiments.•Parametrical studies are carried out to optimize build ...quality and flexural modulus.•All responses are mainly affected by layer thickness, air gap and number of contours.•The optimization of key parameters greatly improves build quality and flexural modulus.
Fused deposition modeling (FDM) is a growing 3D printing technique widely practiced around the world in various industrial applications because of its ability to create complex 3D objects and geometries. Reduction of build time and feedstock material consumption without compromising the mechanical performance is the major concern in most industrial applications affecting the cost and the functionality of the manufactured part. One of the key issues of FDM process is how to select the correct parameters to reduce the build time and to reduce feedstock material consumption while maintaining high dynamic mechanical properties. In this study, influence of critical FDM parameters—layer thickness, air gap, raster angle, build orientation, road width, and number of contours—are studied using Q-optimal response surface methodology. Their effects on build time, feedstock material consumption and dynamic flexural modulus are critically examined. Mathematical models have been formulated to develop a functional relationship between the processing conditions and the process quality characteristics. Analysis of variance (ANOVA) technique was employed to check the adequacy and significance of mathematical models. Moreover, the optimal setting of process parameters was determined. A confirmation test was also conducted in order to verify the developed models and the optimal settings. The results show that Q-optimal design is a very promising method in FDM process parameter optimization. The results also confirm the adequacy of the developed models.
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The aim of this paper was to explore tablet design options for FDM 3D printing for simultaneous tailoring of drug release and dose. The drug, griseofulvin (GF), the polymer, ...hydroxypropyl cellulose (HPC), and processing temperatures were selected to avoid confounding effects arising from drug-polymer interactions. Filaments containing 0–30 wt% GF were prepared using a twin-screw extruder. Five tablet designs were printed using combinations of fixed or varying drug-concentration filaments, fixed or varying tablet sizes, or placebo and drug-rich regions. Two of five options met the main objective; varying drug-concentration filaments for fixed tablet size or printing fixed size duo-tablet having internal placebo regions of varying sizes. Analysis of the drug dissolution profiles revealed that the tablet surface area to volume (SA/V) ratio was the dominant factor, a higher SA/V ratio resulted in a faster release rate, mostly independent of the drug amount or its placement within the tablet. Use of HPC led to near zero-order release for most cases. For duo-tablets, long lag times proportional to placebo shell-thickness were observed. These results suggest that design options other than varying the tablet size would be needed to achieve desired drug release from FDM-based 3D printed personalized dosages.
In this study, a wood fiber/polylactic acid composite (WPC) filament was used as feedstock to print the WPC part by means of fused deposition modeling (FDM). The morphology and mechanical properties ...of WPC parts printed at different speeds (30, 50, and 70 mm/s) were determined. The results show that the density of the printed WPC part increased as the printing speed decreased, while its surface color became darker than that of parts printed at a high speed. The printing time decreased with an increasing printing speed; however, there was a small difference in the time saving percentage without regard to the dimensions of the printed WPC part at a given printing speed. Additionally, the tensile and flexural properties of the printed WPC part were not significantly influenced by the printing speed, whereas the compressive strength and modulus of the FDM-printed part significantly decreased by 34.3% and 14.6%, respectively, when the printing speed was increased from 30 to 70 mm/s. Furthermore, scanning electronic microscopy (SEM) illustrated that the FDM process at a high printing speed produced an uneven surface of the part with a narrower width of printed layers, and pull-outs of wood fibers were more often observed on the fracture surface of the tensile sample. These results show that FDM manufacturing at different printing speeds has a substantial effect on the surface color, surface roughness, density, and compressive properties of the FDM-printed WPC part.
As one of the most important raw materials for fused deposition modeling (FDM) 3D printing, polyamide (PA) is widely used in many fields because of its excellent properties. For PA FDM, the ...parameters are highly important to the performance of the printed parts without doubt. Herein, the effect of two main printing parameters (nozzle temperature and layer thickness) on the mechanical properties and tribological properties of FDM-printed PA were investigated. Results show that the mechanical properties of PA increase yet the wear rate reduces with the increase of nozzle temperature from 240 °C to 260 °C, while the friction coefficient (COF) shows few variation. With the increase of layer thickness from 0.1 mm to 0.3 mm, the mechanical properties decline, while the COF increases. Surprisingly, polishing of the 3D printed PA increases the COF to the range of 0.40 to 0.60 from about 0.05 of unpolished, which is attributed to the disappearance of the smooth and hard surface layer caused by extrusion after polishing. For demonstrate, planetary gears were manufactured with the optimized parameters of nozzle temperature of 260 ℃ and layer thickness of 0.1 mm, found running stably at 200 rpm/min without any noise.
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•Nozzle temperature has little effect on the COF of PA, while can reduce the wear rate.•FDM-printed PA without polishing treatment is self-lubricated, of which the COF can reach about 0.05.•The properties of FDM-printed PA with a nozzle temperature of 260 ℃ and a layer height of 0.1 mm are optimal.
In this study, continuous carbon-fiber reinforced thermosetting composites were prepared using 3D printing followed by characterization of their mechanical properties. First, a 3D printing platform ...was fabricated to prepare the composites based on Fused Deposition Modeling (FDM). Then, the composites lamina and grids were manufactured using a FDM-based platform. Finally, the mechanical properties of the composite lamina were characterized. The results showed that the mechanical performance of the 3D printed thermosetting composites was superior to that of similar 3D printed thermoplastic composites and 3D printed short carbon fiber reinforced composites.
•A 3D printing platform was fabricated to prepare the thermosetting composites.•The composites lamina and grids were manufactured using a FDM-based platform.•The mechanical properties of the composite lamina were characterized.•The mechanical properties of these novel printed thermosetting composites were better than others.
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