Infill Ratio Research Articles

Effect of infill pattern and ratio on the flexural and vibration damping characteristics of FDM printed PLA specimens

3D printing technology has started to be used in many different areas of our lives. In this study, the panels' flexural behaviors and vibration-damping capabilities produced in different infill patterns (Grid, Cross, and Tri-hexagon) and different infill ratios (0%, 20%, 40%, 60%, 80%, and 100%) were investigated. The specimen dimensions were 12.7 mm in width, 127 mm in length, and 3.2 mm in thickness. A biopolymer polylactic acid (PLA) filament with Ø 1.75 mm was used to produce test specimens. Fused Deposition Modeling is a modern additive manufacturing technique; however, optimization is needed to enhance the properties of 3D-printed parts. The flexural properties, as well as vibration-damping characteristics of the 3D-printed specimen, were evaluated experimentally. The results show that the infill pattern and ratio significantly affect flexural behavior and vibration-damping properties. The flexural tests showed that the highest flexural strength was obtained in the Tri-hexagon pattern, while the highest damping capability was obtained on Cross pattern specimens. Additionally, with the increasing infill ratio, the flexural modulus, and flexural strength increase. The specific strength value obtained for the 20% fill rate for all patterns was observed as maximum Best damping properties were obtained on a 40% infill ratio with all the different tested patterns. This study also showed that infill pattern and ratio design could improve the plastic parts' properties, and 3D printing provides an easy way to test the properties of different infill patterns and ratios.

Comparative study about dimensional accuracy and form errors of FFF printed spur gears using PLA and Nylon

In the present paper the comparison of dimensional accuracy and form errors of FFF (Fused Filament Fabrication) 3D printed spur gears obtained in two different polymeric materials (PLA and Nylon-PA6) is presented. Two types of gears were designed and printed, having different module and teeth number. First, the gear modelling process is presented. The printing parameters were defined for both materials. Then, the measuring processes were described. Using the method of the sector span, the base circular thickness and the base pitch of the gears were determined. Additionally, the root and tip diameters were measured, and their roundness and concentricity errors were determined. The analysis of the results shows that, in general, PLA allows obtaining better dimensional accuracy than Nylon. Nylon parts, which were obtained with lower infill ratio than PLA parts showed lower from errors.

Methods of Preparation and Performance Evaluation of ABS/Mineral Microsphere Composites Produced through FDM and Compression Molding.

The use of amorphous microspheres as filler in composites is promising due to their light weight, low cost, incombustibility, and the ability to alter relevant properties of the final composite. Contrary to glass spheres, perlite microspheres are much cheaper and can be tailor-made to facilitate purpose-oriented alteration of the final composite. We report the use of perlite microspheres for the preparation of: (1) composites, through a compression molding (hot pressing) technique; and (2) composite filaments, in a single screw extruder, as well as their use for sample printing through Fused Deposition Modeling (FDM). Proper characterization of the produced composites allows for their evaluation in terms of physical, thermal, and mechanical properties and with regards to the manufacturing technique, the filler fraction, and size. Composite samples of acceptable quality in terms of filler survival and dispersion as well as mechanical properties were produced through compression molding using fine expanded perlite microspheres (<90 μm) up to an infill ratio of 40 vol.%. Fine fillers (<90 μm) performed well in FDM, allowing printing of composite dogbone samples with a higher Young’s modulus and elongation and similar ultimate tensile strength compared to benchmark, up to an infill ratio of 20 vol.%. Composite samples present a slightly lower burning rate compared to those produced solely by ABS. Perlite microspheres present good workability in both applications, possessing satisfactory performance as filler in the composites, and can thus be assumed a promising multifunctional filler for various thermoplastics considering their low price, environmental impact, and fire rating.

A Case Study on the Effect of Printing Temperature on the Tensile Strength of 3D Printed Parts with PLA Material

Abstract The fusion between the layers of a 3D printed part greatly influences the overall mechanical properties and can reduce its applications in certain domains. In order to obtain a better bonding between layers a study on the influence of printing temperature on the tensile strength of 3D printed parts is needed. The mechanical experiments were made on printed parts with polylactic acid material (PLA) on an open-source 3D printer with filament fabrication technology (FFF). The study is made on parts with the same layer height, infill ratio, dimensions, printed at the same speed. The obtained results show the influence of material printing temperature and the fast cooling on the mechanical properties of the 3D printed parts.

Effect of infill ratio on fracture toughness of Fused Filament Fabrication (FFF) polymeric adhesive joints

ABSTRACT In order to optimize the stiffness/weight ratio and to reduce the manufacturing time, Additive Manufacturing (AM) components are built up by a solid skin and a partially filled core. The filled/total volume ratio is called infill ratio and it is one of the printing parameters to be selected. Since the infill ratio affects the global as well as the local adherend stiffness, i.e. the stiffness close to the joint interface, this paper aims at exploring the effect of this parameter on the Mode I fracture toughness of adhesive joints of AM materials, for a given infill pattern. Therefore, PLA (PolyLactic Acid) AM adherends have been manufactured with an FFF (Fused Filament Fabrication) printer at infill ratios ranging between 20% and 100% and bonded with a structural epoxy adhesive to form a DCB (Double Cantilever Beam) joint for Mode I fracture toughness testing. Finite Element (FE) simulation of a stationary crack in the adhesive layer has been done to evaluate the strain energy release rate along the crack front at different infill ratios in order to highlight local changes in its distribution that can correlate the variation of fracture toughness with infill ratio recorded in the experiments.

Investigation of in-situ chemical cross-linking during fused filament fabrication process on parts shrinkage reduction and interlayer adhesion

The fast shrinkage nature and volume reduction after printing are the main problems whereby semi-crystalline polymers like polypropylene (PP) are not commonly used as a fused filament fabrication material. Finding a solution to shrinkage reduction, therefore, is of great importance. This work has formulated peroxide-coagent modified PP filament to suit the fused filament fabrication (FFF) process to reduce shrinkage through in-situ cross-linking. The peroxide-coagent composition was optimized through the melt-mixing study by evaluating the processing temperature and peroxide-coagent concentration. Experimental results were confirmed the in-situ bond formation during printing and the impact on printed samples' shrinkage and mechanical performance. Several printing parameters (printing temperature, infill ratio, layer height) were evaluated to obtain a 3D printed sample with less shrinkage. The sample printed at 245 °C with 0.2 mm layer height and 100% infill was found to have a higher gel content and improved welding between the adjacent layers, enhancing the mechanical property and reducing shrinkage on the printed part. The elevated bed and printing temperature helped keep the layer in a partially liquefied stage during printing, making pressure relaxation and progress in inter-layer adhesion. Generally, this work expands PP utilization in the FFF 3D printing process and provides insight into the cross-linking during 3D printing.

Effect of Infill Ratio on the Tensile and Flexural Properties of Unreinforced and Carbon Fiber-Reinforced Polylactic Acid Manufactured by Fused Deposition Modeling

Parts printed by fused deposition modeling (FDM) are used as tool aids and functional prototypes, and it is necessary to improve their mechanical properties to broaden their application. In this study, the influence of the infill ratio on mechanical properties was investigated using polylactic acid (PLA) and 15 wt.% carbon fiber-reinforced PLA (CFPLA). The FDM process was used to produce tensile and flexural samples with infill ratios of 0%, 20%, 40%, 60%, 80% and 100%. The results show that the mechanical properties of both materials were enhanced gradually as the infill ratio increased, and this effect was more pronounced for PLA. The ultimate tensile strength (UTS) was higher for PLA than for CFPLA for all infill ratios; a maximum UTS of 35.65 MPa (100% infill ratio) was obtained for PLA. Conversely, a lower UTS (18.78 MPa) was recorded for CFPLA with a same infill ratio due to (i) higher porosity, (ii) weak interface bonding and (iii) low adhesion of CF/matrix. In general, PLA samples were stiff, while CFPLA was ductile for all infill ratios. On the other hand, PLA was more resistant to bending; with an infill ratio of 100%, PLA reached a maximum value of 78.32 MPa, and it was 43.34 MPa stronger than CFPLA. The analyses of specific tensile strength and specific flexural strength showed that the infill ratio of 50% produced poor mechanical properties for all samples. The infill ratio parameter should be considered when designing FDM parts, especially when the strength-to-weight ratio is important.

Mechanical properties of thermoplastic parts produced by fused deposition modeling:a review

PurposeThis paper aims to provide an overview of the recent findings of the mechanical properties of parts manufactured by fused deposition modeling (FDM). FDM has become a widely used technique for the manufacturing of thermoplastic parts. The mechanical performance of these parts under service conditions is difficult to predict due to the large number of process parameters involved. The review summarizes the current knowledge about the process-property relationships for FDM-based three-dimensional printing.Design/methodology/approachThe review first discusses the effect of material selection, including pure thermoplastics and polymer-matrix composites. Second, process parameters such as nozzle temperature, raster orientation and infill ratio are discussed. Mechanisms that these parameters affect the specimen morphology are explained, and the effect of each parameter on the strength of printed parts are systematically presented.FindingsMechanical properties of FDM-produced parts strongly depend on process parameters and are usually lower than injection-molded counterparts. There is a need to understand the effect of each parameter and any synergistic effects involved better.Practical implicationsThrough the optimization of process parameters, FDM has the potential to produce parts with strength values matching those produced by conventional methods. Further work in the field will make the FDM process more suitable for the manufacturing of load-bearing components.Originality/valueThis paper presents a critical assessment of the current knowledge about the mechanical properties of FDM-produced parts and suggests future research directions.

Compressive Behavior of Gyroid Structures Manufactured Through SLM with Carburizing Steels: A Numerical and Experimental Study

Triply periodic minimal surfaces such as Gyroid structures have been widely used in additive manufacturing as a strategy to reduce material usage, printing time, and part weight, which are of high interest by the automotive industry. Most Software dedicated to additive manufacturing have lattice tools for infill available, but they usually do not consider the influence of the infill strategy on the part‘s mechanical properties. Therefore, this study analyzed numerically and experimentally the influence of lattices on the compressive behavior of samples manufactured by selective laser melting and developed a procedure to use the finite element method as a tool for mechanical properties evaluation. The procedure employed the software nTopology to generate gyroid structures and Ansys for the structural analyses. Different gyroid densities were numerically analyzed and samples with the best weight/stress ratio were selected for experimental validation with compression tests according to the ASTM E9 standard. The material considered was a carburizing steel DIN 5120 suitable for industrial applications. The results showed that the infill percentage is not associated with a linear relationship between weight and stress. It was observed that besides the infill ratio, the material distribution has a significant effect on the sample performance, which was affected by the stress concentration phenomena. A good representativity was found between the numerical model and experiments, enabling it as a reliable method to evaluate how the infill affects mechanical behavior

Optimization of fused deposition modeling process using a virus-evolutionary genetic algorithm

Fused Deposition modelling (FDM) is one of the most widely used Additive Manufacturing technologies that extrude a melted plastic filament through a heated nozzle in order to build final physical models layer-by-layer. In this research, a virus-evolutionary genetic algorithm (MOVEGA) is developed and implemented to solve a multi-objective optimization problem related to fused deposition modelling. Taguchi approach was first employed for the experimental procedure design and nine test parts were built according to L9 orthogonal array. The examined process parameters were the deposition angle, layer thickness, and infill ratio each one having three levels. Infill pattern was constant to honeycomb selection. Fabrication time of ABS (Acrylonitrile-Butadiene-Styrene) 3D printed specimens was measured during experiments and analyzed by using Analysis of Means (ANOM) and Analysis of Variance (ANOVA) techniques. Shape accuracy was measured by considering the parts’ dimensions in X, Y and Z axes and expressed as the overall error for control. Regression models were developed to use them as objective functions for a group of multi-objective optimization algorithms. Multi-objective Greywolf (MOGWO), and multi-universe (MOMVO) algorithms where also selected for optimizing the FDM problem to compare results. To evaluate the algorithms and judge superiority with reference to the non-dominated solution sets obtained, the hypervolume indicator was adopted. It has been verified that MOVEGA exhibited superiority in its performance for optimizing FDM problems when compared to heuristics such as MOGWO and MOMVO algorithms whilst it has strong potentials to be coupled with “Internet of Things” (IoT) platforms to facilitate the intelligent optimization control referring to a range of resources, consumables and software.

Additive manufacturing introduced substructure and computational determination of metamaterials parameters by means of the asymptotic homogenization

Metamaterials exhibit materials response deviation from conventional elasticity. This phenomenon is captured by the generalized elasticity as a result of extending the theory at the expense of introducing additional parameters. These parameters are linked to internal length scales. Describing on a macroscopic level, a material possessing a substructure at a microscopic length scale calls for introducing additional constitutive parameters. Therefore, in principle, an asymptotic homogenization is feasible to determine these parameters given an accurate knowledge on the substructure. Especially in additive manufacturing, known under the infill ratio, topology optimization introduces a substructure leading to higher-order terms in mechanical response. Hence, weight reduction creates a metamaterial with an accurately known substructure. Herein, we develop a computational scheme using both scales for numerically identifying metamaterials parameters. As a specific example, we apply it on a honeycomb substructure and discuss the infill ratio. Such a computational approach is applicable to a wide class substructures and makes use of open-source codes; we make it publicly available for a transparent scientific exchange.

Effect of fused deposition modeling process parameters on the mechanical properties of recycled polyethylene terephthalate parts

AbstractFused deposition modeling (FDM) filaments made of recycled materials are desirable for environmentally friendly and sustainable manufacturing of prototypes and load‐bearing components in many applications. We investigate the effect of FDM process parameters on the mechanical properties of 3D‐printed parts made of recycled polyethylene terephthalate (rPET) filaments. Increasing the nozzle temperature from 230°C to 260°C improves the strength of the specimens by 100%. Using a raster orientation parallel to the loading direction improves the ductility by more an order of magnitude. Specimen orientation and infill ratio also influence the mechanical properties. The temperature and the orientation effects are related to the quality of fusion between the printed lines. A modified Gibson‐Ashby model correctly predicts the strength as a function of the infill ratio. Through the optimization of process parameters, the mechanical strength of 3D‐printed rPET structures can reach that of injection‐molded PET, making FDM a suitable manufacturing technique for load‐bearing applications.

Power consumption investigation for fused filament fabricated specimen

This paper describes a research project comparing various settings of current 3D printers and the effect on part quality and machine efficiency. The goal of this research is to determine the most appropriate parameters with which to 3D print any component. The chosen settings should provide a final product of quality while being efficient within three categories: print completion time, part weight, and Kilowatt-per-hour consumption. The purpose being to establish a set of parameters that will provide the sought-after efficiency on any fused filament fabrication (FFF) 3D printer, in any application, for any production part. These parameters could prove to benefit additive manufacturing (AM), saving time, material, and electrical energy cost. This study provides results for the most efficient settings across three parameters: layer height, infill ratio, and shell count. Through testing, given the experimental set-up and parameters, 0.3 mm, 3 shells, 25% infill was the most efficient array of settings in this application.

Customized Novel Design of 3D Printed Pregabalin Tablets for Intra-Gastric Floating and Controlled Release Using Fused Deposition Modeling.

Three-dimensional (3D) printing has been recently employed in the design and formulation of various dosage forms with the aim of on-demand manufacturing and personalized medicine. In this study, we formulated a floating sustained release system using fused deposition modeling (FDM). Filaments were prepared using hypromellose acetate succinate (HPMCAS), polyethylene glycol (PEG 400) and pregabalin as the active ingredient. Cylindrical tablets with infill percentages of 25%, 50% and 75% were designed and printed with the FDM printer. An optimized formulation (F6) was designed with a closed bottom layer and a partially opened top layer. Filaments and tablets were characterized by means of fourier-transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), X-ray powder diffraction (XRPD), and thermogravimetric analysis (TGA). The results show that the processing condition did not have a significant effect on the stability of the drug and the crystallinity of the drug remained even after printing. A dissolution study revealed that drug release is faster in an open system with low infill percentage compared to closed systems and open systems with a high infill ratio. The optimized formulation (F6) with partially opened top layer showed zero-order drug release. The results show that FDM printing is suitable for the formulation of floating dosage form with the desired drug release profile.

Robust design application for optimizing ABS fused filament fabrication process: A case study

The current paper is a case study of optimizing fused filament fabrication (FFF) process using robust design. FFF process is a low cost 3d printing process that uses ABS (Acrylonitrile-Butadiene-Styrene) filament in order to build progressive layer by layer, physical prototypes. Four (4) parameters having three levels each ones is used (Deposition angle, Layer thickness, Infill ratio, Infill pattern). The quality indicator that used for the optimization process is the dimensional accuracy. It was found that the layer thickness is the most important parameter in the reported experimental area.

Fused filament fabrication 3D printing with low-melt alloys

3D-printing polymers using fused filament fabrication (FFF) technology has shown to fabricate complex functional parts for electronic, automotive, and biomedical applications. However, there is limited knowledge and understanding of 3D printing with pure metal feedstock using FFF technology. The use of 3D printing of metals and its alloys using FFF technology can provide low-cost alternatives and solutions to the laser-powder bed fusion process. In current work, low-melting eutectic alloy of bismuth (58% Bi, 42% Sn), non-eutectic alloy of bismuth (40% Bi, 60% Sn), and a non-eutectic alloy of antimony (7.5% Sb, 89% Sn) have been used as a starting material and evaluated for FFF 3D printing using two approaches. In the first approach, a low-melting alloy in the form of wire was used as the feedstock for FFF extrusion. In this approach, the influence of FFF process parameters such as infill ratio, extrusion velocity, feed rate, nozzle temperature and bed temperature on the part fabrication were evaluated for successful fabrication of 2D and 3D geometries and characterized for density, precision, mechanical properties, and microstructure. In the second approach, low-melting alloys were cast onto 3D-printed molds to create metal structures. With this approach, the fabricated specimens were evaluated for its part formability, density, precision, mechanical properties, and microstructure. In addition, both approaches were used to fabricate a prototype specimen such as a souvenir and a prototype wrench. It is expected that such a technology will pave the way for the affordable fabrication of metal prototypes and alternatively on-demand custom metal spare parts for in-space applications and future space missions.

Dual-objective Analysis for Desktop FDM Printers: Energy Consumption and Surface Roughness

FDM printing has become familiar and close to the public. Considering its scale, the energy consumption of desktop FDM printers should be attended. Existing research, however, heavily focused on part quality, particularly, surface roughness. In this research, energy consumption and surface roughness were simultaneously considered. Full factorial experiments were designed and conducted, to 1) investigate the impact of key process parameters, including layer thickness, printing speed, and infill ratio, on the energy consumption and surface roughness using one desktop printer, and 2) compare the energy consumption and surface roughness of fabricated parts using a same set of parameters on three different printers. Dual-objective analysis was then performed. Layer thickness was identified as the most influential factor, generating opposite impact on the two objectives. The observed surfaces are relatively rough with uncertainties, such as spikes and wavy curves. It is, therefore, suggested that most desktop printers can be configured primarily for energy savings.

Seismic behavior and modeling of concrete partially filled spirally welded pipes (CPF-SWP)

Hollow spirally welded pipes (SWP) have been used widely as piles for the foundations of buildings, bridges, and flood wall structures. These members have limited ductility due to extensive local buckling and denting when subjected to seismic loading. In cases where improved seismic performance and ductility is required, the SWP are filled, fully or partially, with concrete. Fully filled SWP are called CF-SWP, while partially filled SWP are referred as CPF-SWP. Researchers have experimentally investigated the structural behavior of SWP and CF-SWP. However, there is lack of benchmarked numerical models that can be used to investigate the seismic behavior of SWP, CF-SWP or CPF-SWP, and lack of research regarding the seismic behavior and ductility of CPF-SWP. This paper develops and benchmarks detailed 3D finite element method (FEM) models for evaluating the seismic behavior of SWP, CF-SWP, and CPF-SWP. The FEM models account for behavioral complexities such as steel yielding, pipe local buckling and fracture, concrete cracking and crushing, cyclic stiffness degradation and recovery, and effects of concrete confinement. The FEM models for both the hollow SWP and filled CF-SWP are benchmarked using experimental data available in the literature. The benchmarked models are used to investigate the seismic behavior and ductility of the partially filled CPF-SWP, which include the transition from hollow SWP to filled CF-SWP. These investigations show that the infill ratio (Lc/L) has a significant influence on the seismic behavior of CPF-SWP. Increasing the infill ratio delays the steel pipe local buckling and fracture, and improves the stiffness, strength, ductility, and energy dissipation capacity. Fully filling the plastic hinge region with concrete can significantly improve the seismic behavior of CPF-SWP.

Root Zone Construction Affects Hybrid Bermudagrass (C. Dactylon x C. Transvaalensis) Responses to Simulated Traffic

Few studies have directly compared the types of root zones used for athletic fields. A two-year field study was conducted from 2012-2013 at the University of Tennessee Center for Athletic Field Safety (Knoxville, TN) to compare the performance of four root zones: a silt loam root zone, a sand-based root zone constructed to United States Golf Association (USGA) specifications, a sand-based root zone constructed to ASTM International (ASTM) specifications, and a sand-cap root zone (CAP) consisting of silt loam capped with 15cm of sand that conformed to USGA particle size specifications. Hybrid bermudagrass (C. dactylon x C. transvaalensis, cv. ‘Tifway’) was established over all root zones. In addition to the bermudagrass treatments, two different synthetic turf surfaces varying in fiber type and infill ratio were included for comparison. All treatments were subjected to 30 simulated traffic events each autumn at rates of 0, 3 or 10 simulated traffic events per week in a split-plot design. Differences were only detected in percent green cover only for traffic rate in 2012. In 2013, bermudagrass on silt loam was reduced to 50% cover after ∼10 simulated traffic events, compared to ∼18 simulated traffic events on USGA and ASTM sand-based root zones. Surface hardness varied between treatments and years of the study; however, at no time did any surface exceed surface hardness thresholds associated with head injury (200 Gmax). Despite the loss of hybrid bermudagrass cover from the repeated simulated traffic events, few differences in surface hardness were detected between synthetic turf and hybrid bermudagrass plots in this study, regardless of root zone.

Test &amp;amp; Research on the Shearing Strength of the Continuous Seams in the Mortar-Less Fabricated Block &amp;amp; Masonry

Test &amp; research on the shearing strength of the hollow mortar-less fabricated concrete block &amp; masonry has been done in this article. A proposed formula has been put forward in this article by analyzing the influence of the shear loading methods on the shearing strength using the shearing test data of 27 standard test specimens’ continuous seams divided into 9 groups with 100% concrete infill ratio.