3D Printing Filament Research Articles

3D printing of cellulose nanofiber/polylactic acid composites via an efficient dispersion method

In this study, a green and efficient dispersion method was developed to prepare cellulose nanofiber (CNF) reinforced polylactic acid (PLA) composites for fused deposition modeling (FDM) 3D printing. The CNF/PLA compounds were readily obtained by blending a CNF aqueous suspension with microscale PLA powder, followed by an air-drying process. This method significantly reduced the need for chemical reagents and shortened the processing time. A silane coupling agent and polyethylene glycol (PEG) were used as surface modifiers to enhance the dispersion of CNFs in PLA matrix, and the interfacial interactions between the two constituents in the composite. The CNF/PLA composite filaments for 3D printing were produced using twin-screw cycling extrusion. The test results showed that the incorporation of the surface-modified CNFs effectively enhanced the flowability and the mechanical performance of PLA. The superior mechanical properties of the resulting 3D-printed CNF/PLA composites can be attributed to the uniform dispersion of CNFs in the PLA matrix, higher crystallinity of PLA, and reduced composite defects.

Rapid prototyping of 3d printed micropillars using fused filament fabrication technique for biomedical applications

PurposeThe hygroscopic properties of 3D-printed filaments and moisture absorption itself during the process result in dimensional inaccuracy, particularly for nozzle movement along the x-axis and for micro-scale features. In view of that, this study aims to analyze in depth the dimensional errors and deviations of the fused filament fabrication (FFF)/fused deposition modeling (FDM) 3D-printed micropillars (MPs) from the reference values. A detailed analysis into the variability in printed dimensions below 1 mm in width without any deformations in the printed shape of the designed features, for challenging filaments like polymethyl methacrylate (PMMA) has been done. The study also explores whether the printed shape retains the designed structure.Design/methodology/approachA reference model for MPs of width 800 µm and height 2,000 µm is selected to generate a g-code model after pre-processing of slicing and meshing parameters for 3D printing of micro-scale structure with defined boundaries. Three SETs, SET-A, SET-B and SET-C, for nozzle diameter of 0.2 mm, 0.25 mm and 0.3 mm, respectively, have been prepared. The SETs containing the MPs were fabricated with the spacing (S) of 2,000 µm, 3,200 µm and 4,000 µm along the print head x-axis. The MPs were measured by taking three consecutive measurements (top, bottom and middle) for the width and one for the height.FindingsThe prominent highlight of this study is the successful FFF/FDM 3D printing of thin features (<1mm) without any deformation. The mathematical analysis of the variance of the optical microscopy measurements concluded that printed dimensions for micropillar widths did not vary significantly, retaining more than 65% of the recording within the first standard deviation (SD) (±1 s). The minimum value of SD is obtained from the samples of SET-B, that is, 31.96 µm and 35.865 µm, for height and width, respectively. The %RE for SET-B samples is 5.09% for S = 2,000µm, 3.86% for S = 3,200µm and 1.09% for S = 4,000µm. The error percentage is so small that it could be easily compensated by redesigning.Research limitations/implicationsThe study does not cover other 3D printing techniques of additive manufacturing like stereolithography, digital light processing and material jetting.Practical implicationsThe presented study can be potentially implemented for the rapid prototyping of microfluidics mixer, bioseparator and lab-on-chip devices, both for membrane-free bioseparation based on microfiltration, plasma extraction from whole blood, size-selection trapping of unwanted blood cells, and also for membrane-based plasma extraction that requires supporting microstructures. Our developed process may prove to be far more economical than the other existing techniques for such applications.Originality/valueFor the first time, this work presents a comprehensive analysis of the fabrication of micropillars using FDM/FFF 3D printing and PMMA in filament form. The primary focus of the study is to minimize the dimensional inaccuracies in the 3D printed devices containing thin features, especially in the area of biomedical engineering, by delivering benefits from the choice of the parameters. Thus, on the basis of errors and deviations, a thorough comparison of the three SETs of the fabricated micropillars has been done.

Effect of Post-Drawing Thermal Treatment on the Mechanical Behavior of Solid-State Drawn Poly(lactic acid) (PLA) Filaments

In this work, two commercial extruded filaments for 3D printing obtained from different NatureWorks PLA resins (Ingeo™ Biopolymer 3D850 and Ingeo™ Biopolymer 4043D) were solid-state drawn at varying temperatures and subsequently heat treated by annealing. The aim was to analyze the effect of post-processing of industrial fibers (solid-state drawing and annealing treatment) with varied composition (PLA grades with different contents of D-isomer) on the mechanical performance and thermal stability of the obtained PLA fibers. Morphological, thermal, and mechanical characterizations were performed for the undrawn filaments and drawn fibers, both before and after heat treatment. Drawn fibers presented a fibrillar core–shell structure, and their mechanical properties were greatly improved with respect to undrawn filaments in accordance with their higher crystallinity. The resin with the higher content of D-isomer (4043D) resulted in lower crystallinities with a subsequent decrease in mechanical properties. After heat treatment, drawn fibers exhibited completely different behaviors depending on the PLA resin, with 3D850 fibers being much more stable than 4043D fibers, which underwent molecular orientation upon drawing rather than crystallization. The solid-state drawn fibers obtained herein are comparable to commercial fibers in terms of mechanical properties.

Simple Determination of the Melt Flow Index of Composite Polymer Filaments Used in Material Extrusion Additive Manufacturing

The mechanical properties improving filler introduction into polymer filaments often lead to the formation of defects in 3D-printed products. Studying the bulk modification of polyethylene terephthalate glycol (PETG) filaments with 0.5–1.5 wt% of natural shungite and molybdenum disulfide, we found the melt flow index (MFI) value reduced by 18%–30%. We investigate the effect of bulk modification on the filaments’ rheological properties, develop a technique that eliminates typical additive prototyping defects by regulation of the extrusion parameters in Cura slicing software, and propose an effective method for the MFI-measurement of the 3D-printed filaments that does not require special laboratory equipment (plastometers).

In-house processing of carbon fiber-reinforced polyetheretherketone (CFR-PEEK) 3D printable filaments and fused filament fabrication-3D printing of CFR-PEEK parts

In-house processing of carbon fiber-reinforced polyetheretherketone (CFR-PEEK) 3D printable filaments and fused filament fabrication-3D printing of CFR-PEEK parts

Wall-less Flow Phantoms with 3D printed Soluble Filament for Ultrasonic Experiments

Abstract Tissue-mimicking materials (TMMs) typically used for ultrasound phantoms include gelatin, agarose and polyvinyl alcohol (PVA). These materials have shown sufficient similarity in ultrasound parameters compared to human tissue. Despite their extensive use for years to generate ultrasound phantoms, no simple and easily reproducible way to generate complex, wall-less ultrasound flow phantoms has been introduced. Commercially available ultrasound flow phantoms are limited to simple flow geometries that do not reflect the complex blood flow in humans. Flow phantoms with complex geometries presented in scientific publications either have walls between TMMs and the flow channel, are limited to one material, or are complicated to produce. In this contribution, we present a method using 3D printing and soluble filament that allows for the reliable and consistent production of complex flow geometries with the typical materials used for ultrasound phantoms and without any walls.

STUDY ON CHARACTERISTIC ANALYSIS OF ONYX-CARBON FIBER REINFORCED MATERIAL AT PT. MATAHARI MEGAH

Industry 4.0 focuses on automation with the help of technological and scientific developments in its application. Additive manufacturing is one of the pillars in Industry 4.0. 3D printing technology is part of additive manufacturing. One of the Indonesian companies that utilize 3D printing technology is PT Matahari Megah, the 3D-printing filament used to make a product in the company is Onyx-Carbon Fiber Reinforced. This material is used to make jaw grippers, soft jaws, threads, brackets, and jigs. However, the use of Onyx-Carbon Fiber Reinforced material is still not optimal, because there are no physical strength characteristics of the composite material. The method used in this research is to find a comparative study that starts by looking for literature studies that vary the parameters of the infill pattern and the percentage of density. In this study, the research data will be compared with the data from the literature study which will then be analyzed to find the most optimal parameters, based on the literature, the data obtained will be analyzed using the Taguchi method. From the data analysis, it is found that among the triangular, rectangular, and hexagonal infill patterns, the rectangular pattern is the most optimal. The optimal parameter configuration for the first data is by using rectangular infill pattern with 75% density percentage and for the second data by using rectangular infill pattern with 80% density percentage.

Utilization of PVP-PLA Combination in Fabricating Theophylline-loaded Filament for 3D Printing with Immediate Release Behavior

Fused deposition modeling (FDM), known as a highly effective 3D printing technique, holds promise as an alternative approach to tablet manufacturing. While commonly employing thermoplastic polymers as starting materials, the integration of established pharmaceutical excipients remains unexplored. Polyvinyl pyrrolidone (PVP) is a frequently used excipient known for its potential to confer immediate-release properties to drugs. However, its suitability for extrusion is hindered by its thermal and melt-rheological properties. In contrast, polylactic acid (PLA), which has robust mechanical strength and thermal plasticity, was expected to overcome PVP’s limitations. This study aims to obtain drug-loaded filaments using the combination of PVP and PLA through a hot-melt extrusion process, aiming for favorable mechanical properties and immediate-release behavior. Utilizing a twin-screw extruder, and theophylline was used as the model drug, three formulations were optimized –FP1, FP2, and FP3– containing 0%, 10%, and 20% theophylline, respectively. Subsequent evaluation including filament morphology, mechanical properties, drug content, and drug release profile, were performed to each filament. FP2 emerged as the most promising formulation, with 10.35% (w/w) drug load and over 95% drug released in an hour. All formulations exhibited slightly rough filament surfaces with diameters averaging 1.4-1.6 mm. Notably, an increase in the theophylline content correlates with the diminished filament strength, evident in reduced hardness and a rise in brittleness. This study emphasized the potential of PVP-PLA-based filaments for future pharmaceutical 3D printing formulations, providing immediate drug release characteristics.

(Invited) Poly(lactic acid)-Nanodiamond Composites for Electroanalytical Applications

There has been an exponential increase in the popularity of 3D printing technology in the last few years, also in everyday life. Numerous applications are reported for poly(lactic acid) (PLA) based polymer composites with various conductive carbon fillers for electrochemical needs, such as sensors, batteries, water remediation, etc. The bulk of these reports is based on commercially available 3D printing filaments, with carbon black, graphene or carbon nanotubes as fillers. Regardless of good conductivity, these materials possess characteristics that are suboptimal for electrochemical applications, including charge transfer kinetics, stability to oxidation, electrolytic window, etc.3D printouts offer versatility in terms of ease of cheap and on-demand fabrication of free-standing multielectrode setups e.g. by dual-extruder printing. However, to fully embrace their advantages enhancement of charge transfer kinetics by removing an excess of PLA and uncovering the nanofillers, is needed. Recently we have demonstrated laser ablation for locally sculptured effective modification of the electrochemical response of these materials.There is a great focus on the development of new conductive filaments that exhibit better mechanical, electric, thermal, and electrochemical properties. We have evaluated for the first time various forms of conductive nanodiamonds (ND), i.e. detonation nanodiamonds and diamond-phase rich boron-doped carbon nanowalls, as fillers for PLA-based composites for 3D printing. The goal of the research was to investigate and thoroughly understand the interactions between composite components and those that affect the mechanical parameters and electrochemical characteristics of printed elements, studying how ND addition to PLA matrix affects material strength, rheology, and melting temperature. In particular, the enhancement of electrode kinetics and electrochemically available surface area by ND was revealed and discussed. The authors acknowledge the financial support by The National Science Centre (Republic of Poland) SONATA BIS 2020/38/E/ST8/00409.

Influence of Chemical Pretreatment on the Mechanical, Chemical, and Interfacial Properties of 3D-Printed, Rice-Husk-Fiber-Reinforced Composites

This article explores using biomass, namely rice husks, as a reinforcement material in thermoplastic copolyester (TPC) composites. Rice husks were subjected to three chemical pretreatments: single-stage sulfuric acid hydrolysis, first-stage sulfuric acid hydrolysis followed by a second-stage methanesulfonic acid (MSA) treatment, and first-stage sulfuric acid hydrolysis followed by a second-stage sodium hydroxide alkali treatment. We studied the effects of these treatments on the rheological, thermal, interfacial, and mechanical properties of composites. The fibers were mixed with polymers at high shear rates and temperatures, and 3D-printed filaments were produced using a desktop 3D printer. The printed parts were analyzed using tensile tests, torque and viscosity measurements, and thermogravimetric analysis to obtain their mechanical, rheological, and thermal properties. SEM imaging was performed to understand the fiber–polymer interface and how it affects the other properties. The results showed that first-stage sulfuric acid hydrolysis followed by a second-stage pretreatment of the fibers with MSA showed better fiber–polymer adhesion and a 20.4% increase in stress at 5% strain, a 30% increase in stress at 50% strain, and a 22.6% increase in the elastic modulus as compared to untreated rice husk composites. These findings indicate that readily available and inexpensive rice husks have significant potential for use in natural fiber-reinforced composites when pretreated using dilute sulfuric acid followed by methane sulfonic acid hydrolysis.

Enhancement of sustainable fused deposition modeling 3D‐printing with agave Americana fiber‐reinforced poly(lactic) acid biofilaments

AbstractAdditive manufacturing (AM) of eco‐friendly biocomposites has been growing recently to obtain green fillers capable of reducing bioplastic costs without compromising the material processability and performance. This paper aims to study the effect of using different Agave America fiber volume ratios on the morphological, chemical, and thermal properties, contact angle, and hardness of poly(lactic) acid (PLA) filament for 3D printing. Sustainable biofilaments of PLA filled with 10 and 5 wt% of Agave Americana fiber were prepared in a thermokinetic mixer and extruded in a machine, and then used to print testing samples using fused deposition modeling (FDM) 3D printer. Biofilaments were characterized using scanning electron microscopy (SEM), thermogravimetry (TGA), differential scanning calorimetry (DSC), and Fourier‐transform infrared spectroscopy (FTIR) techniques. The addition of fiber did not significantly influence the biofilament's diameter and density compared to pure PLA. On the other hand, it influenced printed biofilaments' thermal stability and morphological characteristics. The biocomposites developed have shown enhancement in their shore hardness. Thus, the use of Agave Americana fiber reinforced in a PLA matrix did not compromise its thermal properties, nor its processability and printability, which could open the possibility of future research with a biocomposite with higher fiber content and an environmentally friendly alternative over traditional filler materials.

Development and characterization of pla biofilament combined with perifiton biomass for 3d printing

3D printing has conquered markets on an exponential scale. Allied to this, the global demand for environmentally sustainable materials drives research in the search for a substitute for petroleum-based thermoplastics. PLA is among the main raw materials for use in 3D printing filaments and has the advantage of being a bio-based and biodegradable biopolymer. This study aimed to develop a biofilament from a mixture of periphytic biomass and PLA and to evaluate its biodegradability potential when compared to commercial filaments. The biofilament was produced with 95% PLA and 5% periphytic biomass. Scanning Electron Microscopy and FTIR spectroscopy were applied to analyze the morphological structure of the biofilament. The biofilament presented mechanical performance similar to pure PLA, becoming slightly more rigid and brittle. In the biodegradability test, the sample produced with the biofilament showed a greater mass loss, with 63.75%, when compared to the PLA samples, indicating that the presence of microalgae contributed to the degradation of the material.

Tailoring PLA/ABS Blends Compatibilized with SEBS-g-MA through Annealing Heat Treatment.

In this work, blends based on poly (lactic acid) (PLA)/acrylonitrile-butadiene-styrene (ABS) compatibilized with maleic anhydride-grafted (SEBS-g-MA) were prepared in a co-rotational twin-screw extruder by varying the concentrations of the compatibilizing agent. The influence of the compatibilizing agent on the morphology, mechanical, thermal, thermomechanical, and rheological properties of the prepared materials was analyzed. The effect of annealing on the properties of the blends was also investigated using injection-molded samples. The X-ray diffraction (XRD) results proved that the increments in crystallinity were an effect of annealing in the PLA/ABS/SEBS-g-MA blends, resonating at higher heat deflection temperatures (HDTs). The impact strength of the PLA/ABS blends compatibilized with 10 wt% SEBS-g-MA was significantly increased when compared to the PLA/ABS blends. However, the hardness and elastic modulus of the blends decreased when compared to neat PLA. The refined morphology shown in the scanning electron microscopy (SEM) analyses corroborated the improved impact strength promoted by SEBS-g-MA. The torque rheometer degradation study also supported the increased compatibility between SEBS-g-MA, PLA, and ABS. The TGA results show that the PLA/ABS and PLA/ABS/SEBS-g-MA blends are more thermally stable than the neat PLA polymer at higher temperatures. The results showed that the ideal composition is the heat-treated PLA/ABS/SEBS-g-MA (60/30/10 wt%), given the high impact strength and HDT results. The results of this work in terms of mechanical improvement with the use of compatibilizers and annealing suggest that the PLA/ABS/SEBS-g-MA system can be used in the production of 3D-printing filaments.

Development and characterization of sustainable 3D printing filaments using post-consumer recycled PET: processing and characterization

Development and characterization of sustainable 3D printing filaments using post-consumer recycled PET: processing and characterization

Toughness Enhancement of PLA-Based Filaments for Material Extrusion 3D Printing

Poly(lactic acid) (PLA) is one of the most popular biodegradable thermoplastics in the market of 3D printing filaments used in the material extrusion (ME) technique. This is because it can be printed easily at low temperatures. However, its inherent brittleness limits its use in many applications. In this work, the toughness of PLA filament was improved by blending with various types of rubbers including natural rubber (NR), acrylic core–shell rubber (CSR), and thermoplastic polyurethane (TPU) in the amount of 15% by weight. PLA/TPU filament was found to have the smoothest surface with the best shape and dimension stability, while PLA/NR filament rendered the highest tensile toughness. In term of the effect of printing temperature, the highest printing temperature in this study (210°C) provided the highest smoothness with the best shape stability and dimension accuracy. Interestingly, the tensile toughness and elongation at break of 3D printed specimens were found to be higher than those of compression-molded specimens for all filament types. This could be explained by the ability of the 3D printing technique to produce specimens that aligned in the printing direction in a fiber-like pattern.

Carbon-Fiber-Recycling Strategies: A Secondary Waste Stream Used for PA6,6 Thermoplastic Composite Applications.

With a view to achieving sustainable development and a circular economy, this work focused on the possibility to valorize a secondary waste stream of recycled carbon fiber (rCF) to produce a 3D printing usable material with a PA6,6 polymer matrix. The reinforcing fibers implemented in the research are the result of a double-recovery action: starting with pyrolysis, long fibers are obtained, which are used to produce non-woven fabrics, and subsequently, fiber agglomerate wastes obtained from this last process are ground in a ball mill. The effect of different amounts of reinforcement at 5% and 10% by weight on the mechanical properties of 3D-printed thermoplastic composites was investigated. Although the recycled fraction was successfully integrated in the production of filaments for 3D printing and therefore in the production of specimens via the fused deposition modeling technique, the results showed that fibers did not improve the mechanical properties as expected, due to an unsuitable average size distribution and the presence of a predominant dusty fraction ascribed to the non-optimized ball milling process. PA6,6 + 10 wt.% rCF composites exhibited a tensile strength of 59.53 MPa and a tensile modulus of 2.24 GPa, which correspond to an improvement in mechanical behavior of 5% and 21% compared to the neat PA6,6 specimens, respectively. The printed composite specimens loaded with the lowest content of rCF provided the greatest improvement in strength (+9% over the neat sample). Next, a prediction of the "optimum" critical length of carbon fibers was proposed that could be used for future optimization of recycled fiber processing.

Characterization of Hydroxyapatite From Kupang Shells and Its Synthesis with Polycaprolactone for 3D Printing Filament

Characterization of Hydroxyapatite From Kupang Shells and Its Synthesis with Polycaprolactone for 3D Printing Filament

Development of 3D printable cenosphere‐reinforced polyethylene terephthalate glycol (PETG) filaments for lightweight structural applications

AbstractPresent research evaluates the feasibility of producing polyethylene terephthalate glycol (PETG) filaments reinforced with cenosphere (CS), which have great potential to develop syntactic foam composites (SFC) for several applications, that is, from automotive to aerospace. A melt flow extrusion technique was used to reinforce PETG with different weight fractions (i.e., 0, 10, 20, 30, and 40 wt%) cenosphere, and further, the thermal, mechanical, and physical properties of the prepared feedstocks were investigated in detail. Results indicated that Young's modulus, load‐bearing capacity, and ultimate tensile strength of PETG filament with 40 wt% CS were 1652.1 5 MPa, 76.91 1 N, and 31.97 1 MPa, respectively, which is similar to virgin PETG filament. In addition, the porosity of the CS‐reinforced PETG filaments decreased with increasing concentration of the CS in the PETG matrix. Such cenosphere‐filled filaments possess attractive thermo‐mechanical and physical properties to develop high‐quality SFC through additive manufacturing (AM) routine.Highlights PETG/cenosphere based 3D printing filaments were developed. The modulus and strength significantly improved by adding 40% cenosphere. The porosity decreased with increasing cenosphere weight fraction. Addition of cenosphere affected water absorption characteristics of filaments.

Sustainable fabrication of 3D printing filament from recycled PET plastic

The widespread use of plastic is leading to increased plastic waste and environmental concerns globally. This research paper aims to address this issue by investigating the potential of creating a sustainable 3D printing filament using recycled polyethylene terephthalate (PET) bottles. Our experimental setup involved a 1.6 mm diameter nozzle with a heater block to ensure precise temperature control during filament extrusion, resulting in a reliable and repeatable filament diameter of 1. 65 mm.The study focuses on creating a consistent filament with a 1.65 mm diameter using recycled PET bottles. Additionally, finite element analysis (FEA) is conducted using SolidWorks software to compare the mechanical properties of the PET filament to conventional polylactic acid (PLA) material widely used in 3D printing. The FEA simulations analyze stress, strain, and displacement for both PET and PLA materials, and the results are compared to draw conclusions based on the numerical observations. The findings from this research will offer valuable insights into the potential of recycled PET bottles as an environmentally friendly alternative for 3D printing filaments. This work contributes to reducing plastic waste and promotes sustainable practices in additivemanufacturing.

Chemical characterization of particulates and volatile organic compounds emitted during fused deposition modeling

Additive manufacturing (AM) is largely regarded as an environmentally friendly alternative to traditional manufacturing techniques. However, some studies have pointed out that AM may carry its own environmental implications. It has been reported that high concentrations of ultrafine particle emissions as well as volatile and semi volatile organic compound emissions from the fused deposition modeling (FDM) 3D printing process. The health consequences of exposure to these ultrafine particles and organic compounds are unknown. Determining the chemical composition of the ultrafine particles and the volatile organic compounds is the first step toward understanding potential health risks of FDM process. In this study, we collect air emissions from FDM printing using ABS plastic filament for chemical characterization. Using solid phase microextraction (SPME), compounds in samples are adsorbed or absorbed on a fiber coating and analyzed with gas chromatography mass spectrometry (GC–MS). Several compounds are successfully identified in printer emissions and compared with samples collected from filament wash prior to extrusion. The most predominant compound was styrene, followed by various benzene aromatics, nitrogenated aromatics, and siloxanes. Measurements identifies substantial cross over between compounds found from printer emission and filament wash tests, suggesting that some emissions could possibly be reduced, or in some cases, even eliminated by washing 3D printer filament prior to use.