Fused Deposition Modelling Feedstock Research Articles

Effects of Hot-Melt-Extrusion process parameters on the Feedability of Fused Deposition Modeling filaments

Fused deposition modelling (FDM) has shown its advantages in the field of personalized oral medicine due to its low cost, simplicity and flexible manufacturing for on- demand doses. However, most pharmaceutical-grade polymers that can be hot-melt extruded do not have the mechanical properties for high-quality FDM feedstock, and it is considered a barrier to further development of FDM pharmaceutical applications. In this paper, the impacts of Hot- Melt Extrusion (HME) process parameters on the mechanical properties of FDM filaments is explored for the brittle polymer polyvinylpyrrolidone (PVP). The results show that the feed rate greatly influences the mechanical properties of the filaments. Through the exploration of HME process parameters, the preparation method of FDM raw filaments has been further improved, and the application of brittle polymers in FDM pharmaceuticals has been broadened.

Fused deposition modelling of flexible kenaf fiber/thermoplastic polyurethane composites

This work explores the feasibility of fused deposition modelling (FDM) to produce kenaf fiber/thermoplastic polyurethane (TPU) composites. Internal mixer was used for mixing different weight percentage (0, 5 and 10 wt %) of kenaf fiber with TPU before being extruded to produce filament for FDM feed stock. Addition of kenaf fiber was found to give benefits on dimensional stability of the printed samples which is importance for its implementation in FDM. TPU filled with 10wt% of kenaf fibre showed improvements in hardness and Young modulus of 15% and 49%. However, the tensile strength, elongation at break and density of the printed samples decreased with increasing kenaf fiber loading. This could be explained due to increase of voids and porosity within the material and poor wettability between TPU matrix and kenaf fiber which is evidenced by SEM observation.

Study on barium titanate and graphene reinforced PVDF matrix for 4D applications

This article reports the experimental investigations of polyvinylidene fluoride (PVDF) matrix-based composite feedstock filament (reinforced with barium titanate (BTO) and graphene (Gr) for possible 4-D printing applications) using fused deposition modeling (FDM). The mechanical, rheological, thermal, and morphological properties of in-house prepared FDM filament are also reported. The FDM feedstock filament was prepared with a twin-screw extruder (TSE). The process parameters of TSE for preparation of smart material-based filament with uniform dispersion of reinforcement (BTO and Gr) in the PVDF matrix have also been explored. Finally, the prepared filament has been used on FDM setup (without any change in hardware/software) for printing piezoelectric sensor with 4-D capabilities. The results of the study suggest that BTO and Gr have significant effect on the melt flow index of PVDF. The composite prepared with reinforcement of BTO and Gr shows a continuous flow, along with better thermal stability (based upon differential scanning calorimetry analysis), when 10–20 wt% BTO was added to the PVDF matrix. The observed maximum peak and break strength of the PVDF composite was 29.57 MPa and 26.50 MPa, respectively. The scanning electron microscopy and energy-dispersive X-ray analysis results reveal that the filament prepared with 20% BTO and extruded at 200°C with a screw speed of 40 r/min has better dispersion of reinforcement among the selected parametric settings. Finally, a piezoelectric response of 20 pC/N has been measured on the FDM-printed thermally stable sample suitable for 4-D applications.

3D Printing of Photocatalytic Filters Using a Biopolymer to Immobilize TiO2 Nanoparticles

Titanium oxide-based photocatalytic filters were produced by Fused Deposition Modelling (FDM) using biopolymers obtained from renewable biomass resources. The thermoplastic route allows shaping composites through the immobilization of photoactive TiO2 nanoparticles in an environmentally friendly bioplastic such as the polylactic acid (PLA). Composites with an inorganic charge of 30 wt% of TiO2 nanoparticles (NPs) exhibit a 100% methyl orange (MO) degradation after 24 h of light exposition due to the extremely uniform dispersion of the nanophase within the polymer matrix in the FDM feedstock. Surface modification of TiO2 NPs allows the optimization of the colloidal dispersion and stabilization of the inorganic charge in a PLA solution and hence, the optimal distribution of nano-photoactive points in the TiO2/PLA filaments and scaffolds. The proposed new route of processing improves the dispersion of nano-charges comparing with the traditional thermo-pressing routes used for mixing thermoplastics based composites, avoiding the thermal degradation of the polymer and providing a customised product. In this manuscript the evolution of photodegradation with the increase of TiO2 content in the composite and the variation of the filter geometry was evaluated.

Mechanical, thermal and melt flow of aluminum-reinforced PA6/ABS blend feedstock filament for fused deposition modeling

PurposeThis study aims to highlights the mechanical, thermal and melting behavior compatibility of aluminum (Al)-reinforced polyamide (PA) 6/acrylonitrile butadiene styrene (ABS)-based functional prototypes prepared using fused deposition modeling (FDM) from the friction welding point of view. Previous studies have highlighted the use of metallic/non-metallic fillers in polymer matrix for preparations of mechanically improved FDM feedstock filaments and functional prototypes. But hitherto, very less has been reported on fabrication of functional prototypes which fulfill the compatibility of two polymers for joining/welding-based applications. The compatibility of two dissimilar polymers enables the friction welding for maintenance applications.Design/methodology/approachThe twin screw extrusion process has been used for mechanical mixing of metallic reinforcement in polymer matrix, and final blend of reinforced polymers in the form of extruded feed stock filament has been used on FDM for printing of functional prototypes (for friction welding). The methodology involves melt flow index (MFI) investigations, differential scanning calorimetry (DSC) investigations for thermal properties, tensile and hardness testing for mechanical properties and photo micrographic investigations for metallurgical properties on extruded samples.FindingsIt was observed that the reinforced ABS and PA6 polymers have better compatibility in the terms of similar melt flow, thermal properties and can lead to the better joint efficiency with friction welding.Originality/valueIn the present work composite feed stock filament composed of ABS and PA6 with reinforcement of Al powder has been successfully developed for preparation of functional prototype in friction welding applications.

Thermomechanical investigations of SiC and Al2O3–reinforced HDPE

This research work highlights the thermomechanical investigations of silicon carbide (SiC) and aluminum oxide (Al2O3)–reinforced high-density polyethylene (HDPE)–based feed stock filament of commercial fused deposition modeling (FDM) setup. The recycled HDPE waste was collected (from domestic waste) and washed with water jet for removal of contamination in the first stage. After contamination removal, rheological and thermal behavior (melt flow index, melting temperature, decomposition and enthalpy, etc.) of the unreinforced and reinforced polymer matrix was observed. The SiC and Al2O3 reinforcements in the HDPE matrix have been controlled by twin-screw extrusion process, followed by its processing on single-screw extrusion for preparation of FDM feed stock filament. The feed stock filament prepared by single-screw extruder was subjected to tensile test for mechanical properties (such as peak strength, peak load, and Young’s modulus). After ascertaining mechanical properties, multifactor optimization has been performed. Finally, scanning electron micrographs were obtained to understand the distribution of ceramic particles. This study highlights the detailed procedure for managing the polymer waste with improved mechanical properties by considering multifactor optimization. This will enhance the sustainability and also helps to develop low-cost, in-house FDM filament for possible applications as rapid tooling.

Effect of SiC/Al2O3 particle size reinforcement in recycled LDPE matrix on mechanical properties of FDM feed stock filament

ABSTRACTIn this research work, an effort has been made to develop fused deposition modelling (FDM), feed stock filament wire from recycled low-density polyethylene (LDPE) with different particle sizes (i.e. single particle size (SPS), double particle size (DPS) and triple particle size (TPS) in different proportions) of SiC/Al2O3 as reinforcement. After evaluation of melt flow index (MFI), the best combinations were selected and used for filament wire preparation on twin screw extruder. The results of the study highlight that Al2O3-based DPS reinforcement resulted in better mechanical properties of the feed stock filament. Finally, the non-functional prototypes have been printed with feed stock filament prepared on open-source FDM. The Al2O3-based DPS reinforcement in LDPE resulted in better dimensional stability with improved surface hardness. The results have been supported by SEM-based photomicrographs and differential scanning calorimetry (DSC).

Roadmap to sustainable plastic additive manufacturing

As additive manufacturing (AM) is heading towards mass production and mass customization, the process needs to be environment-friendly and energy-efficient in order to be self-sustainable. Selective laser sintering (SLS) and fused deposition modeling (FDM) are two processes contributing massively towards plastic additive manufacturing. In SLS, the powders that do not contribute to the mass of products become unusable (after some number of reuse) and finally turn into waste. As high energy is required for production of powders, generation of these wastes impacts environment sustainability. A contrivance needs to be developed to convert these waste powders into high-value products to make the process sustainable. FDM has the largest market share in terms of number of AM systems sold and is the most popular for fabricating low-value products. Its usefulness will be further expanded if inexpensive high-value products could be made through this process. In the present work, waste SLS powder is employed to prepare feedstock for inexpensive high-value FDM products, which demonstrates that SLS refuse could be utilized for mass production of FDM feedstock. If two processes (SLS & FDM) will be connected as proposed here, it will make plastic additive manufacturing energy-efficient, self-sustainable, and will contribute to environment sustainability, in general.

3D printing of high drug loaded dosage forms using thermoplastic polyurethanes

It was the aim of this study to develop high drug loaded (>30%, w/w), thermoplastic polyurethane (TPU)-based dosage forms via fused deposition modelling (FDM). Model drugs with different particle size and aqueous solubility were pre-processed in combination with diverse TPU grades via hot melt extrusion (HME) into filaments with a diameter of 1.75 ± 0.05 mm. Subsequently, TPU-based filaments which featured acceptable quality attributes (i.e. consistent filament diameter, smooth surface morphology and good mechanical properties) were printed into tablets. The sustained release potential of the 3D printed dosage forms was tested in vitro. Moreover, the impact of printing parameters on the in vitro drug release was investigated. TPU-based filaments could be loaded with 60% (w/w) fine drug powder without observing severe shark skinning or inconsistent filament diameter. During 3D printing experiments, HME filaments based on hard TPU grades were successfully converted into personalized dosage forms containing a high concentration of crystalline drug (up to 60%, w/w). In vitro release kinetics were mainly affected by the matrix composition and tablet infill degree. Therefore, this study clearly demonstrated that TPU-based FDM feedstock material offers a lot of formulation freedom for the development of personalized dosage forms.

On the wear properties of Nylon6-SiC-Al 2 O 3 based fused deposition modelling feed stock filament

Fused deposition modelling (FDM) is one of the commonly used additive manufacturing (AM) technologies. In commercial FDM setup a plastic material based filament (usually of ABS) is unwound from a coil to produce functional/non-functional prototypes. The application domain of FDM is limited presently, because of selective material availability in commercial market as regards to the wear of functional prototypes is concerned. In order to enhance the application domain of commercial FDM setup, an effort has been made to develop new polymer composite (with hybrid reinforcement) wire of Nylon6-SiC-Al2O3 with enhanced wear resistant properties. In this research work experimental investigations has been carried out for optimizing wear properties of Nylon6-SiC-Al2O3 based feed stock filament of FDM. Further mathematical model for above mentioned property has been developed and counter verified as a case study.

Incorporation of graphitic nano‐filler and poly(lactic acid) in fused deposition modeling

ABSTRACTThis article presents research results showing that the property of fused deposition modeling (FDM) products is obtained jointly by careful control of processing parameters, structure of products, and the composition of material. In this manuscript, poly(lactic acid) (PLA) was incorporated with graphene or carbon nanotube (CNT) through repeated melt blending. Filament of the PLA/graphitic nano‐filler was prepared and used in FDM. Rheological and thermal analysis were conducted to assess the suitability of the composite as FDM feedstock, and mechanical and electrical property were tested subsequently. Research results demonstrate that filament diameter‐regarded as processing‐related parameter‐was positively correlated with mechanical stiffness and strength of FDM products. Tensile elongation at break of FDM products exhibited significant increase at a raster angle of 45° compared with the filament before FDM, showing in certain cases, material property depends more on the structure than the composition. And when incorporated with graphene or CNT, the electrical conductivity of the PLA‐based composite increased drastically. The electrical conductivity of the best experiment sample reached ∼10−1 S m−1, demonstrating that composition is the key to functionalizing material. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 44703.

Modelling the Peak Elongation of Nylon6 and Fe Powder Based Composite Wire for FDM Feedstock Filament

In the present work, to increase the application domain of fused deposition modelling (FDM) process, Nylon6–Fe powder based composite wire has been prepared as feed stock filament. Further for smooth functioning of feed stock filament without any change in the hardware and software of the commercial FDM setup, the mechanical properties of the newly prepared composite wire must be comparable/at par to the existing material i.e. ABS, P-430. So, keeping this in consideration; an effort has been made to model the peak elongation of in house developed feedstock filament comprising of Nylon6 and Fe powder (prepared on single screw extrusion process) for commercial FDM setup. The input parameters of single screw extruder (namely: barrel temperature, temperature of the die, speed of the screw, speed of the winding machine) and rheological property of material (melt flow index) has been modelled with peak elongation as the output by using response surface methodology. For validation of model the result of peak elongation obtained from the model equation the comparison was made with the results of actual experimentation which shows the variation of ±1 % only.

Investigations for melt flow index of Nylon6-Fe composite based hybrid FDM filament

Purpose This paper aims to carry out experimental investigations highlighting the role of melt flow index (MFI) in fused deposition modelling (FDM) process by varying the proportion of the Fe powder which is being used as a filler material. An attempt has been made to standardize MFI of Nylon6-Fe composite material to be used as hybrid FDM filament. Design/methodology/approach In this research work, it is proposed to make a suitable blend of composite material for FDM filament which can be used directly for rapid tooling applications. Three controllable parameters (namely, composition/proportion of the filler for hybrid filament, extrusion temperature and extrusion load) were studied by using Taguchi L9 orthogonal array (O.A.) MFI which is an indication of flowability has been selected as output parameter. Findings MFI of hybrid composite filament material has been studied, and Taguchi’s L9 O.A. was applied under both the conditions of lower the better type and larger the better type. It is observed that the contribution of the extrusion load, extrusion temperature and proportion of the filler material is almost similar, whether lower the better type situation is considered or larger the better type is considered. Further, an attempt has been made to standardize the MFI of Nylon6-Fe composite material for industrial applications, as no standard is available for composites (presently, ASTM-D-1238-95 standard is being used for plastic based materials only). Originality/value In recent past, researchers have studied and analysed the flow of the material through the nozzle of the FDM machine, but very little work has been reported on study of the flow characteristics of filament material before the composite material is fed into the machine. This research can open new avenues in the field of MFI and deals with comparison of MFI of the existing FDM feedstock material with the new composite material. The developed feedstock material is ferromagnetic in nature and can find wide variety of industrial applications.