scholarly journals Design of Self-Supported 3D Printed Parts for Fused Deposition Modeling

Author(s):  
Fabian Lischke ◽  
Andres Tovar

One of the primary challenges faced in Additive Manufacturing (AM) is reducing the overall cost and printing time. A critical factor in cost and time reduction is post-processing of 3D printed (3DP) parts, of which removing support structures is one of the most time consuming steps. Support is needed to prevent the collapse of the part or certain areas under its own weight during the 3D printing process. Currently, the design of self-supported 3DP parts follows a set of empirical guide lines. A trial and error process is needed to produce high quality parts by Fused Depositing Modeling (FDM). The usage of chamfer angle with a max 45° angle form the horizontal for FDM is a common example. Inclined surfaces with a smaller angle are prone to defects, however no theoretical basis has been fully defined, therefore a numerical model is needed. The model can predict the problematic areas at a print, reducing the experimental prints and providing a higher number of usable parts. Physical-based models have not been established due to the generally unknown properties of the material during the AM process. With simulations it is possible to simulate the part at different temperatures with a variety of other parameters that have influence on the behavior of the model. In this research, analytic calculations and physical tests are carried out to determine the material properties of the thermoplastic polymer Acrylonitrile - Butadiene - Styrene (ABS) f or FDM at the time of extrusion. This means that the ABS is going to be extruded at 200°C to 245°C and is a viscous material during part construction. Using the results from the physical and analytical models, i.e., Timoshenko’s modified beam theory for micro-structures, a numerical material model is established to simulate the filament deformation once it is deposited onto the part. Experiments were also used to find the threshold for different geometric specifications, which could then be applied to the numerical model to improve the accuracy of the simulation. The result of the finite element analysis is compared to experiments to show the correlation between the prediction of deflection in simulation and the actual deflection measured in physical experiments. A case study was conducted using an application that optimizes topology of complex geometries. After modeling and simulating the optimized part, areas of defect and errors were determined in the simulation, then verified and and measured with actual 3D prints.

Polymers ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 1559
Author(s):  
Mohammad Reza Khosravani ◽  
Jonas Schüürmann ◽  
Filippo Berto ◽  
Tamara Reinicke

Application of Additive Manufacturing (AM) has significantly increased in the past few years. AM also known as three-dimensional (3D) printing has been currently used in fabrication of prototypes and end-use products. Considering the new applications of additively manufactured components, it is necessary to study structural details of these parts. In the current study, influence of a post-processing on the mechanical properties of 3D-printed parts has been investigated. To this aim, Acrylonitrile Butadiene Styrene (ABS) material was used to produce test coupons based on the Fused Deposition Modeling (FDM) process. More in deep, a device was designed and fabricated to fix imperfection and provide smooth surfaces on the 3D-printed ABS specimens. Later, original and treated specimens were subjected to a series of tensile loads, three-point bending tests, and water absorption tests. The experimental tests indicated fracture load in untreated dog-bone shaped specimen was 2026.1 N which was decreased to 1951.7 N after surface treatment. Moreover, the performed surface treatment was lead and decrease in tensile strength from 29.37 MPa to 26.25 MPa. Comparison of the results confirmed effects of the surface modification on the fracture toughness of the examined semi-circular bending components. Moreover, a 3D laser microscope was used for visual investigation of the specimens. The documented results are beneficial for next designs and optimization of finishing processes.


2019 ◽  
Vol 26 (2) ◽  
pp. 288-298 ◽  
Author(s):  
Oğuzhan Emre Akbaş ◽  
Onur Hıra ◽  
Sahar Zhiani Hervan ◽  
Shahrad Samankan ◽  
Atakan Altınkaynak

Purpose This paper aims to analyze experimentally and numerically the effect of the nozzle temperature and feed rates on the dimensions of the fused deposition modeling (FDM) polymer parts. Design/methodology/approach In total, 30 strips per sample were printed with the same width as the nozzle diameter. The strips were printed with one vertical movement of the nozzle head. The width of the strips was measured with a caliper at five locations. A linear regression model was created based on the experimental data to understand the correlation between the strip width deviation and the parameters of interest. Numerical simulations were performed to predict the swell of the polymer exiting the nozzle using finite element method combined with level set method. The experimental results were then used to validate the models. Findings The average accuracy of polylactic acid (PLA) samples was better than that of acrylonitrile butadiene styrene (ABS) samples. The average strip width had a tendency to increase with increasing temperature for PLA samples, whereas ABS samples showed mixed behavior. The strip width decreased with increasing feed rate for most cases. The measurement positions had a major effect on strip width when compared to nozzle temperature and feed rate. The numerical model predictions were in good agreement with the experimental data. A few discrepancies were observed at high feed rates and nozzle temperatures. Originality/value This study will contribute to gaps in knowledge regarding the effect of processing conditions on dimensional accuracy of FDM-printed parts. The developed numerical model can be efficiently used to predict the dimensional accuracy of FDM-printed parts.


Author(s):  
Kamaljit Singh Boparai ◽  
Gurpartap Singh ◽  
Rupinder Singh ◽  
Sarabjit Singh

Abstract In this work, 3D printed master patterns of acrylonitrile butadiene styrene (ABS) thermoplastic material have been used for the preparation of Ni-Cr based functional prototypes as partial dentures (PD). The study started with patient specific three dimensional (3D), CAD data (fetched through scanning). This data was used for preparation of .STL file for printing of master patterns on fused deposition modeling (FDM) setup. The 3D printed master patterns were further wax coated to reduce the surface irregularities (as cost effective post processing technique). The hybrid patterns were subjected to investment casting for the preparation of Ni-Cr based PD. The finally prepared functional prototypes as PD were optimized for dimensional accuracy, surface finish and surface hardness as responses. The results are visualized and supported by photomicrographs and in-vitro analysis.


Polymers ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 2792
Author(s):  
Mohammadreza Lalegani Dezaki ◽  
Mohd Khairol Anuar Mohd Ariffin

Fused deposition modeling (FDM) is commonly used to print different products with highly complex features. Process parameters for FDM are divided into controllable or uncontrollable parameters. The most critical ones are built orientation, layer thickness, infill pattern, infill density, and nozzle diameter. This study investigates the effects of combined infill patterns in 3D printed products. Five patterns (solid, honeycomb, wiggle, grid, and rectilinear) were combined in samples to analyze their effects on mechanical properties for tensile strength analysis. Polylactic acid (PLA) samples were printed in different build orientations through two directions: flat and on-edge. The limitation was that the software and machine could not combine the infill patterns. Thus, the patterns were designed and assembled in computer aided design (CAD) software. Finite element analysis (FEA) was used to determine the patterns’ features and results showed honeycomb and grid have the highest strength while their weights were lighter compared to solid. Moreover, 0° samples in both flat and on-edge direction had the strongest layer adhesion and the best quality. In contrast, perpendicular samples like 60° and 75° showed poor adhesion and were the weakest specimens in both flat and on-edge, respectively. In brief, by increasing the build orientation, the strength decreases in this study.


2014 ◽  
Vol 660 ◽  
pp. 89-93 ◽  
Author(s):  
Nasuha Sa'ude ◽  
Mustaffa Ibrahim ◽  
Mohd Halim Irwan Ibrahim

This paper presents the melt flow behavior (MFB) of an acrylonitrile butadiene styrene (ABS), High Density Polyethlene (HDPE), Polyproplene (PP) and a combination of ABS-Iron in the extrusion process. In this study, the effect MFB of variety's polymers and ABS mix with 10% Iron material was investigated based on the viscosity, density, thermal conductivity, melting temperature and specific heat material properties. The MFB of FDM system was investigated using Finite-Element Analysis (FEA) by ANSYS CFX 12. Based on the result obtained, it was found that, the material velocity increase when the nozzle diameter is smaller than the entrance diameter. The higher temperature distribution along the MFB of ABS mix with 10% Iron is 43.15 K compared with original ABS, which is 539.15K.


2021 ◽  
Vol 877 ◽  
pp. 67-72
Author(s):  
Niño B. Felices ◽  
Bryan B. Pajarito

Epoxysilane-treated muscovite (ETM) was used as reinforcing filler to 3D-printed acrylonitrile butadiene styrene (ABS) via fused deposition modeling (FDM). Its effects to the mechanical and thermal properties of ABS were investigated. ETM was loaded at 1, 3, and 5wt%. ABS/ETM composites were characterized via scanning electron microscopy (SEM), tensile test, differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). Mechanical reinforcement of ABS was observed for ABS/ETM composites loaded at 1 and 3 wt% wherein it was noted that the tensile strength and elastic modulus increased by up to 83.6% and 76.6%, respectively. Reinforcement was brought by interfacial adhesion of ETM with the ABS matrix. There was a sharp decline in mechanical properties for ABS/ETM composites loaded at 5wt% due to agglomeration of ETM in the matrix and discontinuities in the printed layers. The glass transition temperature (Tg) of ABS increased and the onset of its degradation shifted towards higher temperatures with the addition of ETM. It can be concluded that the addition of ETM to ABS for FDM 3D printing improved its mechanical and thermal properties.


Author(s):  
Karl Jin Ang ◽  
Katherine S. Riley ◽  
Jakob Faber ◽  
Andres F. Arrieta

Using fused deposition modeling (FDM) 3D printing, we combine a bio-inspired bilayer architecture with distributed pre-stress and the shape memory behavior of polylactic acid (PLA) to manufacture shells with switchable bistability. These shells are stiff and monostable at room temperature, but become elastic and bistable with fast morphing when heated above their glass transition temperature. When cooled back down, the shells retain the configuration they were in at the elevated temperature and return to being stiff and monostable. These programmed deformations result from the careful design and control of how the filament is extruded by the printer and therefore, the resulting directional pre-stress. Parameter studies are presented on how to maximize the pre-stress for this application. The shells are analyzed using nonlinear finite element analysis. By leveraging the vast array of geometries accessible with 3D printing, this method can be extended to complex, multi-domain shells, including bio-inspired designs.


Polymers ◽  
2019 ◽  
Vol 11 (7) ◽  
pp. 1094 ◽  
Author(s):  
Valentina Mazzanti ◽  
Lorenzo Malagutti ◽  
Francesco Mollica

As biodegradable thermoplastics are more and more penetrating the market of filaments for fused deposition modeling (FDM) 3D printing, fillers in the form of natural fibers are convenient: They have the clear advantage of reducing cost, yet retaining the filament biodegradability characteristics. In plastics that are processed through standard techniques (e.g., extrusion or injection molding), natural fibers have a mild reinforcing function, improving stiffness and strength, it is thus interesting to evaluate whether the same holds true also in the case of FDM produced components. The results analyzed in this review show that the mechanical properties of the most common materials, i.e., acrylonitrile-butadiene-styrene (ABS) and PLA, do not benefit from biofillers, while other less widely used polymers, such as the polyolefins, are found to become more performant. Much research has been devoted to studying the effect of additive formulation and processing parameters on the mechanical properties of biofilled 3D printed specimens. The results look promising due to the relevant number of articles published in this field in the last few years. This notwithstanding, not all aspects have been explored and more could potentially be obtained through modifications of the usual FDM techniques and the devices that have been used so far.


2020 ◽  
Vol 129 (12) ◽  
pp. 1168-1173 ◽  
Author(s):  
Alexandra McMillan ◽  
Armine Kocharyan ◽  
Simone E. Dekker ◽  
Elias George Kikano ◽  
Anisha Garg ◽  
...  

Objective: To identify 3D-printed temporal bone (TB) models that most accurately recreate cortical mastoidectomy for use as a training tool by comparison of different materials and fabrication methods. Background: There are several different printers and materials available to create 3D-printed TB models for surgical planning and trainee education. Current reports using Acrylonitrile Butadiene Styrene (ABS) plastic generated via fused deposition modeling (FDM) have validated the capacity for 3D-printed models to serve as accurate surgical simulators. Here, a head-to-head comparison of models produced using different materials and fabrication processes was performed to identify superior models for application in skull base surgical training. Methods: High-resolution CT scans of normal TBs were used to create stereolithography files with image conversion for application in 3D-printing. The 3D-printed models were constructed using five different materials and four printers, including ABS printed on a MakerBot 2x printer, photopolymerizable polymer (Photo) using the Objet 350 Connex3 Printer, polycarbonate (PC) using the FDM-Fortus 400 mc printer, and two types of photocrosslinkable acrylic resin, white and blue (FLW and FLB, respectively), using the Formlabs Form 2 stereolithography printer. Printed TBs were drilled to assess the haptic experience and recreation of TB anatomy with comparison to the current paradigm of ABS. Results: Surgical drilling demonstrated that FLW models created by FDM as well as PC and Photo models generated using photopolymerization more closely recreated cortical mastoidectomy compared to ABS models. ABS generated odor and did not represent the anatomy accurately. Blue resin performed poorly in simulation, likely due to its dark color and translucent appearance. Conclusions: PC, Photo, and FLW models best replicated surgical drilling and anatomy as compared to ABS and FLB models. These prototypes are reliable simulators for surgical training.


Author(s):  
Rupinder Singh ◽  
Inderpreet Singh ◽  
Ranvijay Kumar

The utilization of thermosetting waste is a serious issue as it is not recycled commercially due to inherent molecular properties and high technology cost. This research details the study of the mechanical behavior and surface analysis with energy-dispersive X-ray spectroscopy and scanning electron microscope of three-dimensional printed parts of the waste thermosetting polymer, bakelite (BAK) as the reinforcement along with ceramic particles (SiC and Al2O3) in recycled thermoplastic acrylonitrile butadiene styrene matrix for sustainability. The process involves twin-screw extrusion for the preparation of filament, followed by 3D printing of functional prototypes on fused deposition modeling setup. The 3D printed parts prepared with fused deposition modeling were used for the testing of mechanical, thermal, and morphological properties. The results of the present study suggests that for commercial applications recycling of thermoplastic up to 10 wt% can be easily performed without a change in any hardware/ software configuration of the fused deposition modeling setup and the ceramic concentration in thermoplastic-thermosetting blends further led to better mechanical and surface properties.


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