Open-source Fused Deposition Modeling Research Articles

Enhanced mechanical characteristics of polylactic acid/tamarind kernel filler green composite filament for 3D printing

AbstractThe significance and interest of printing green composites in three dimensions have recently grown, especially in light of the possibility of reusing waste to produce green fillers that can reduce the cost of biopolymers without compromising their processability and performance outcomes from a mechanical and environmental perspective. In the current work, the kernel powder obtained from the seeds of Tamarindus indica (TI) was added to polylactic acid (PLA) and extruded as a filament in the single screw extruder. It was then printed using an open source Fused Deposition Modeling printer and investigated for its density, mechanical, surface, and morphological characteristics. It was found that the composite performed better when the filler concentration was maintained at 2%, but when it went beyond that, the performance depreciated because of the rapid rise in material voids. When compared with a neat PLA matrix, 2% TI filler offered better overall strength, with increments of 12.64%, 19.87%, and 15.57% in tensile, compression, and flexural strength, respectively. The addition of TI filler was found to promote crystallization within the PLA matrix, leading to a higher degree of crystallinity which have contributed to higher strength. The morphological study demonstrated that the occurrence of uniform filler distribution and inter‐layer randomized bonding at 2% TI/PLA offered superior strength, whereas at higher TI concentrations it led to pullout and delamination. On the other hand, the hardness of the composite increased proportionally to the concentration of the fillers.

Effect of ultrasonic vibration on the mechanical properties of 3D printed acrylonitrile butadiene styrene and polylactic acid samples

Fused deposition modeling (FDM) is an extrusion-based AM process that is widely used due to its cost-effectiveness and user friendly. However, FDM also has some limitations such as the appearance of seam lines between layers and the production of excess material residue leading to poor surface finish, poor bonding between layers and porosity. This paper presents the findings on the application of ultrasonic vibration in an open-source FDM 3D printer to investigate its effect on the mechanical properties and microstructure of acrylonitrile butadiene styrene (ABS) and Polylactic Acid (PLA) samples. Two units of ultrasonic piezoelectric transducer were clamped horizontally on the surface of the 3D printer platform. The ultrasonic vibration was transmitted directly to the platform while the sample received vibration with a specific frequency while the printing process commences. Two process parameters, namely build orientation and ultrasonic vibration were selected to analyze their significance and optimization on the mechanical properties and the microstructure of the printed samples. High compressive and low surface roughness are required to have the best properties for the printed sample. Therefore, the optimization parameters are performed with these settings where the compressive strength is maximized and the surface roughness is minimized. The result shows that the overall compressive strength in ABS and PLA samples created in the Z-axis orientation is higher than in the X-axis orientation. However, the compressive strength of ABS and PLA samples is not much different after the ultrasonic vibration was applied during the printing process. The microstructure analysis shows that bonding between the layers is similar when applying ultrasonic vibration for both ABS and PLA samples. Furthermore, the result indicates that the surface roughness increased at 10 kHz and then decreased or became smoother at 20 kHz for both ABS and PLA material samples. The analysis shows that the build orientation significantly affects the compressive strength in ABS and PLA samples. However, the ultrasonic vibration has no considerable impact. In surface roughness, the build orientation and ultrasonic vibration significantly affect ABS samples. However, the PLA samples are only slightly affected. The optimum parameters for both materials are found where Z-axis orientation and 0 kHz of the ultrasonic vibration samples gave the best compressive strength and surface roughness value.

A 3D-Printed Soft Haptic Device with Built-in Force Sensing Delivering Bio-Mimicked Feedback.

Haptics plays a significant role not only in the rehabilitation of neurological disorders, such as stroke, by substituting necessary cognitive information but also in human-computer interfaces (HCIs), which are now an integral part of the recently launched metaverse. This study proposes a unique, soft, monolithic haptic feedback device (SoHapS) that was directly manufactured using a low-cost and open-source fused deposition modeling (FDM) 3D printer by employing a combination of soft conductive and nonconductive thermoplastic polyurethane (TPU) materials (NinjaTek, USA). SoHapS consists of a soft bellow actuator and a soft resistive force sensor, which are optimized using finite element modeling (FEM). SoHapS was characterized both mechanically and electrically to assess its performance, and a dynamic model was developed to predict its force output with given pressure inputs. We demonstrated the efficacy of SoHapS in substituting biofeedback with tactile feedback, such as gripping force, and proprioceptive feedback, such as finger flexion-extension positions, in the context of teleoperation. With its intrinsic properties, SoHapS can be integrated into rehabilitation robots and robotic prostheses, as well as augmented, virtual, and mixed reality (AR/VR/MR) systems, to induce various types of bio-mimicked feedback.

APPLICATION OF TAGUCHI METHOD TO OPTIMIZE FUSED DEPOSITION MODELING PROCESS PARAMETERS FOR SURFACE ROUGHNESS

Surface quality is one of the limiting aspects of additive manufacturing (AM). This paper presents the findings from a study to optimize Fused Deposition Modeling (FDM) process parameters to improve the surface roughness of the printed test specimen. Taguchi 3⁴ and L9 orthogonal array were used to design the experiment. Samples models of the same size were fabricated with an open source FDM printer using acrylonitrile butadiene styrene (ABS) material and were examined to see the structural differences. Taguchi method S/N ratio and means analysis was used to find the optimum process parameter for surface roughness. The results indicate that flow rate is the most influential process parameter towards better surface roughness, followed by layer height, printing temperature and print speed. The surface roughness of printed test specimen was found to be rougher with the increase in levels of flow rate. The flow rate is responsible for the unevenly aligned section of the deposited filament. It was discovered that the optimal proses parameter levels for surface roughness by the CR-10S Pro FDM machine are 0.1 mm of layer height, 90% of flow rate, 230°C of printing temperature, and 35mm/s of print speed. Thus, Taguchi method has proven to be a useful approach for optimizing parameters to improve the surface roughness of printed parts.

InvestigationofMechanicalPropertiesofRecycledABSPrintedwithOpenSourceFDM PrinterIntegratedwithUltrasoundVibration

Additive Manufacturing (AM) is a process that deposits materials on a platform to form 3D objects layers by layers. One of the downsides of AM is wastage generated during the printing process. Acrylonitrile Butadiene Styrene (ABS) is a popular material used in AM for thermoplastics. This study focused on the feasibility of using recycled ABS for the 3D printing process via an open source Fused Deposition Modeling (FDM)printer. The recycling process began by re-granulating the ABS waste and turning it into a new filament that used to print the test specimens. The experiment was carried out on the mechanical properties of the test specimens, and a comparison was made with the standard ABS specimens. The results showed that recycled ABS could be converted intofilaments with an extrusion temperature of 270°C and a travel speed of conveyor at 18 mm/s. The results of mechanical properties showed recycled specimen had 32% and 28% reduction in flexural and tensile strength of the printed material, respectively, while an 82% increase in the compression strength due to multiple recycling cycles. With the aid of ultrasound vibration (20 kHz) onto the recycled ABS specimen, the results showed a 53% increase in flexural strength, 59% increase in compression strength and 19% increase in tensile strength comparing with 0 kHz of recycled ABS specimen. Overall, the recycled ABS waste is a viable option for better use of printed materials and, with the aid of ultrasound vibration, it helps to improve the mechanical properties of the recycled ABS.

A 3D Printed Modular Soft Gripper Integrated With Metamaterials for Conformal Grasping.

A single universal robotic gripper with the capacity to fulfill a wide variety of gripping and grasping tasks has always been desirable. A three-dimensional (3D) printed modular soft gripper with highly conformal soft fingers that are composed of positive pressure soft pneumatic actuators along with a mechanical metamaterial was developed. The fingers of the soft gripper along with the mechanical metamaterial, which integrates a soft auxetic structure and compliant ribs, was 3D printed in a single step, without requiring support material and postprocessing, using a low-cost and open-source fused deposition modeling (FDM) 3D printer that employs a commercially available thermoplastic poly (urethane) (TPU). The soft fingers of the gripper were optimized using finite element modeling (FEM). The FE simulations accurately predicted the behavior and performance of the fingers in terms of deformation and tip force. Also, FEM was used to predict the contact behavior of the mechanical metamaterial to prove that it highly decreases the contact pressure by increasing the contact area between the soft fingers and the grasped objects and thus proving its effectiveness in enhancing the grasping performance of the gripper. The contact pressure can be decreased by up to 8.5 times with the implementation of the mechanical metamaterial. The configuration of the highly conformal gripper can be easily modulated by changing the number of fingers attached to its base to tailor it for specific manipulation tasks. Two-dimensional (2D) and 3D grasping experiments were conducted to assess the grasping performance of the soft modular gripper and to prove that the inclusion of the metamaterial increases its conformability and reduces the out-of-plane deformations of the soft monolithic fingers upon grasping different objects and consequently, resulting in the gripper in three different configurations including two, three and four-finger configurations successfully grasping a wide variety of objects.

On Nanographene-Reinforced Polyvinylidene Fluoride Composite Matrix for 4D Applications

In past two decades, number of studies has been reported on 3D printing of polyvinylidene fluoride (PVDF) composite matrix. But hitherto, little has been reported on 4D applications of graphene(Gr)-reinforced PVDF for maintenance and repair of heritage structures, especially for self-assembly applications. In this work, mechanical blending of Gr (size 5-10 nm)-reinforced PVDF has been reported for 4D applications as possible on-line maintenance tool for heritage structures. The Gr was blended in four different weight proportions in PVDF matrix. The effect of varying Gr proportion was studied on basis of rheological properties (melt flow index (MFI) and viscosity) required for processing on open source fused deposition modeling (FDM) setup. The various proportions/compositions of the composites were also investigated for thermal stability based upon differential scanning calorimetry (DSC) analysis (required for heritage structure). The selected proportion/composition of feed stock filament were processed on twin screw extruder (TSE) followed by mechanical testing on universal testing machine (UTM). The results of the MFI and viscosity outlined that blending of Gr in PVDF decreases the MFI and increases the viscosity of the composite matrix. The DSC testing showed that PVDF-10%Gr composite have heat capacity of − 64 J/g (during heating cycle). The maximum peak strength of 43.01 N/mm2 was observed, while processing at screw temperature 195 °C with 0.3 Nm torque for filament wire preparation. Finally the 3D printing of selected composition/ proportion was also successful. The piezoelectric properties of composite were observed after direct current (DC) poling by dielectric constant measurement (D33 = 45 pC/N), which is sufficient for self expansion/contraction properties. The feed stock samples prepared were counter verified by performing morphological analysis. For self-assembly applications, vibration sample magnetometry (VSM) was performed. The results are also supported by Fourier transformed infrared spectroscopy (FTIR) analysis for ascertaining bonding characteristics corresponding to observed mechanical properties.

Design, Modeling, and Control of a 3D Printed Monolithic Soft Robotic Finger With Embedded Pneumatic Sensing Chambers

This article presents a directly 3-D printed soft monolithic robotic finger with embedded soft pneumatic sensing chambers (PSC) as position and touch sensors. The monolithic finger was fabricated using a low-cost and open-source fused deposition modeling 3-D printer that employs an off-the-shelf soft and flexible commercially available thermoplastic polyurethane. A single soft hinge with an embedded PSC was optimized using finite element modeling and a hyperelastic material model to obtain a linear relationship between the internal change in the volume of its PSC and the corresponding input mechanical modality, to minimize its bending stiffness and to maximize its internal volume. The soft hinges with embedded PSCs have several advantages, such as fast response to very small changes in their internal volume (~0.0026ml/°), linearity, negligible hysteresis, repeatability, reliability, long lifetime, and low power consumption. Also, the flexion of the soft robotic finger was predicted using a geometric model for use in real-time control. The real-time position and pressure/force control of the soft robotic finger were achieved using feedback signals from the soft hinges and the touch PSC embedded in the tip of the finger. This article contributes to the development of seamlessly embedding optimized sensing elements in the monolithic topology of a soft robotic system and controlling the robotic system using the feedback data provided by the sensing elements to validate their performance.

Amplitude Uniformity in Ultrasonic Assisted Fused Deposition Modeling

Fused Deposition Modeling (FDM) is one of the Additive Manufacturing (AM) technology. Ultrasonic-assisted FDM system has been proven to improve the mechanical properties of the printed specimens. This study aims to explore the uniformity of the amplitude of ultrasonic vibration that was used during the printing process. The uniformity of vibration affected the improvement of the mechanical properties of the 3D printed part. If there is a bad uniformity of ultrasonic vibration, it will influence and increase the variation of the tensile test result. An open-source FDM printer attached with the piezoelectric transducer in various locations of the printer platform was set up. Five different positions and numbers of piezoelectric transducer were set up in order to determine the best position and number of the piezoelectric transducer for transmitting the vibration uniformly to the printing platform. A laser scanning vibrometer was used to determine the amplitude of ultrasonic vibration that transmitted over the printing platform of an open-source FDM 3D printer. From the results, it shows that with two piezoelectric transducers at “Position 4” improved the uniformity of ultrasonic vibration as it had the lowest standard deviation. The test also revealed that the ultrasonic vibration effect uniformly on the 3D printed specimens. In addition, it also reduces the variation and provide better tensile test results of the printed specimens

Investigation of tensile properties of sprayed aluminium based PLA composites fabricated by FDM technology

Fused Deposition Modeling (FDM) has gained widespread popularity among researchers working in area of material science, medical implants and new product development. FDM is used by many industries for prototyping and end-use components due to lower cost and its versatility of material usage. Researchers have used variety of reinforcements for enhancement of mechanical properties of feedstock filament used for FDM. A novel technique has been developed to manufacture FDM composites using alternate layers of sprayed aluminium and Poly Lactic Acid (PLA) filament utilizing open source FDM printer. This study investigates the tensile properties of metal sprayed thermoplastic components and their possible interaction with other process parameters i.e. infill density and bed temperature of FDM printer using Taguchi and ANOVA techniques. Higher tensile strength of composites has been experienced as compared to both virgin PLA components and aluminium spray coated FDM parts. The study demonstrates that the tensile properties are significantly impacted by infill density and number of stacked layers of metal spray; peak strength is directly proportional to infill density while inversely proportional to number of layers.

A 3D-Printed Omni-Purpose Soft Gripper

Numerous soft grippers have been developed based on smart materials, pneumatic soft actuators, and underactuated compliant structures. In this article, we present a three-dimensional (3-D) printed omni-purpose soft gripper (OPSOG) that can grasp a wide variety of objects with different weights, sizes, shapes, textures, and stiffnesses. The soft gripper has a unique design that incorporates soft fingers and a suction cup that operate either separately or simultaneously to grasp specific objects. A bundle of 3-D-printable linear soft vacuum actuators (LSOVA) that generate a linear stroke upon activation is employed to drive the tendon-driven soft fingers. The support, fingers, suction cup, and actuation unit of the gripper were printed using a low-cost and open-source fused deposition modeling 3-D printer. A single LSOVA has a blocked force of 30.35 N, a rise time of 94 ms, a bandwidth of 2.81 Hz, and a lifetime of 26 120 cycles. The blocked force and stroke of the actuators are accurately predicted using finite element and analytical models. The OPSOG can grasp at least 20 different objects. The gripper has a maximum payload-to-weight ratio of 7.06, a grip force of 31.31 N, and a tip blocked force of 3.72 N.

3D Printable Linear Soft Vacuum Actuators: Their Modeling, Performance Quantification and Application in Soft Robotic Systems

Conventional robotic systems have proved their versatility in the industry where complex tasks requiring high force, high speed and high precision are desired. However, these rigid-bodied systems cannot collaborate safely with humans. Soft robots which are primarily made of highly compliant materials bring robots and humans together by operating safely in unstructured environments. Soft robots demand dexterous soft actuators that preserve or enhance their softness and safety features. This article reports on modeling, performance quantification, and soft robotic applications of directly three-dimensional (3-D) printed linear soft vacuum actuators (LSOVA), that are manufactured in a single step, using a low-cost and affordable open-source fused deposition modeling 3-D printer. Numerical and experimental results presented show that LSOVA have multiple advantages including high bandwidth (∼6.49 Hz), high output force (∼27 N) and long lifetime (∼21 500 cycles). LSOVA blocked force and linear stroke can be predicted accurately using finite element and analytical models. Furthermore, LSOVA are scalable. The soft actuators can be either assembled in parallel as a bundle, where a linear relationship exists between the number of actuators and the output force or can be scaled up in terms of internal volume where a linear relationship exists between the output force and the internal volume of a single actuator. Finally, LSOVAs were tailored for various robotic applications including soft crawling robots for navigation in tubular systems, soft parallel manipulators for pick and place tasks, soft artificial muscles, soft prosthetic fingers for prosthetic hands, and soft adaptive grippers for gripping applications.

3D printing of polymeric tissue engineering scaffolds using open-source fused deposition modeling

Open-source printing is a field where the cost of printing additive manufacturing products is cheaper due to more economical software and parts to construct a product including those of tissue engineering scaffolds. In this manuscript, fused deposition modeling (FDM) is used as the main avenue of open-source use in 3D printing of tissue engineering scaffolds. Additive manufacturing enables the researchers to build 3D products with interior and exterior architectures precisely defined and produced using open-access software which dictates the printer to print the models or the data obtained by various imaging techniques. In this way, implants to suit the dimensions and the mechanical and physicochemical properties needed for an artificial extracellular matrix can be produced. The main limitations are the limited number of printing materials and their unknown compositions which make their biocompatibility an issue. With the recent developments of in-house filament production, this limitation is also being overcome.

Multimaterial printing and characterization for mechanical and surface properties of functionally graded prototype

In this work, an effort has been made for multimaterial three-dimensional printing of functionally graded prototypes of polylactic acid matrix (tensile specimens as per ASTM D638 type IV) followed by characterization of mechanical and surface properties. The work is an extension of previous reported studies on twin-screw extrusion process for the preparation of multimaterial wires as feedstock filaments in possible three-dimensional printing applications. The results of the study suggest that the highest peak strength (46.28 MPa) and break strength (41.65 MPa) was obtained for multimaterial three-dimensional printed samples at infill density 100%, infill angle 45°, and infill speed of 90 mm/s on commercial open source fused deposition modeling setup. Further surface hardness measurements performed on two extreme surfaces (top surface comprising magnetite (Fe3O4)-reinforced polylactic acid and bottom with polylactic acid without any reinforcement) revealed that the hardness for the bottom layer was more than the hardness for the top layer. From fractured surface analysis (using photomicrographs), it has been observed that the three-dimensional printed samples with low infill density resulted into more void formation due to which the performance while mechanical testing was poor in comparison to samples printed with higher infill density. The results are also supported by rendered images of photomicrographs, which revealed that high roughness value of samples printed with low infill density was also one of the reasons for poor mechanical performance of multimaterial three-dimensional printed functionally graded prototypes.

Development of PLA-HAp-CS-based biocompatible functional prototype: A case study

In this article, detailed procedure for the development of polylactic acid (PLA), hydroxyapatite (HAp) and chitosan (CS)-based biocompatible functional prototype has been outlined by using three-dimensional (3D) printing as a case study. The biocompatible composite-based feedstock filament (comprising of PLA-HAp-CS) has been prepared through twin-screw extruder (TSE) for open-source fused deposition modelling (FDM)-based 3D printer. This case study provides two-stage multifactor optimization: (a) for preparation of feedstock filament on TSE and (b) 3D printing on FDM based upon tensile and flexural samples. The results of study suggest that the best settings of input parameters for TSE are barrel temperature of 190°C, screw speed of 140 r/min and dead weight of 12 kg. Further, the optimized settings for FDM are layer thickness of 0.2 mm, deposition angle of 30/45° and infill density of 100%. The results have been supported by scanning electron microscopic analysis.

On Development of Functionally Graded Material Through Fused Deposition Modelling Assisted Investment Casting from Al2O3/SiC Reinforced Waste Low Density Polyethylene

The recycling of packaging materials such as low density polyethylene (LDPE) into useful product is one of the challenging tasks. Since waste LDPE has some issues like low mechanical strength and thermal degradation; some studies have been reported in recent past to improve these properties with ceramic/metallic reinforcements. In this work reusability of LDPE has been ascertained as functionally graded material (FGM) through aluminum (Al) matrix based investment casting (IC). This study highlights the use of SiC and Al2O3 as reinforcement in LDPE for IC applications as a novel method for development of FGM. The master patterns for IC were prepared from reinforced LDPE based feed stock filament (prepared on conventional screw extruder) on open source fused deposition modelling setup. The in-house prepared filament wire was subjected to mechanical and thermal testing to ensure recyclability and stability of the material. The photo micrographs and SEM images were collected to ensure the dispersion of SiC and Al2O3 reinforcements in Al based FGM.

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).

Sustainability of Recycled ABS and PA6 by Banana Fiber Reinforcement: Thermal, Mechanical and Morphological Properties

In the present study efforts have been made to prepare functional prototypes with improved thermal, mechanical and morphological properties from polymeric waste for sustainability. The primary recycled acrylonitrile butadiene styrene (ABS) and polyamide 6 (PA6) has been selected as matrix material with bio-degradable and bio-compatible banana fibers (BF) as reinforcement. The blend (in form of feed stock filament wire) of ABS/PA6 and BF was prepared in house by conventional twin screw extrusion (TSE) process. Finally feed stock filament of ABS/PA6 reinforced with BF was put to run on open source fused deposition modelling based three dimensional printer (without any change in hardware/software of the system) for printing of functional prototypes with improved thermal/mechanical/morphological properties. The results are supported by photomicrographs, thermographs and mechanical testing.

RESOURCE-EFFICIENT PROCESS CHAINS TO MANUFACTURE PATIENT-SPECIFIC PROSTHETIC FINGERS

The high cost of quality prostheses, together with the lack of trained prosthetists, makes it challenging to obtain prosthetic devices in developing communities. Modern 3D digitising techniques and additive manufacturing (AM) technologies are gaining popularity in the bio-medical industry and, in the case of prosthesis production, reduce the need for a trained prosthetist. The objective of this research was to develop a new resource-efficient process chain for the manufacturing of prosthetic fingers using additive manufacturing technologies, and to compare it with the traditional (Sculptor) process chain. Fused deposition modelling (FDM), open-source FDM, 3-dimensional printing (3DP), and stereolithography (SLA) were evaluated in terms of their costs, time, material usage, and aesthetic quality. The surface qualities produced with the different additive manufacturing technologies were also compared. The results showed that 3DP was the preferred technology and was the best candidate for the production of prosthesis in terms of cost, quality, and time for developing communities. SLA produced the highest aesthetic quality prosthesis, but was the most expensive. It was concluded that using the additive manufacturing technology process chain to produce prosthetic fingers is faster and more cost effective than the traditional method.

Impact absorption capacity of 3D-printed components fabricated by fused deposition modelling

Despite additive manufacturing emerging as an effective alternative to conventional manufacturing methods, ought partially to the support of open source communities, little is known about the shock absorbing properties of the parts produced. An open source fused deposition modelling device was employed to fabricate 3D polymeric structures and their shock mitigating properties were evaluated. The effect of commercially available layer heights, infill patterns and density on the energy dissipation properties of the printed PLA (polylactic acid) cylinders was examined. A strong dependency of the apparent density on the impact absorption capacity, both in terms of sock mitigation and energy dissipation, of the components was determined whereas the effect of layer height was less pronounced and that of the filling pattern negligible. Results showed that porous specimens were prone to process parameter changes, an effect, gradually fading towards higher densities.