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![Figure 1. Different common infill geometries at various densities [17].](profile/Lorenzo-Bergonzi/publication/349762134/figure/fig1/AS:997554074443776@1614846833424/Different-common-infill-geometries-at-various-densities-17_Q320.jpg)
Fused Deposition Modelling (FDM) is one of the most widespread additive manufacturing technologies due to its relatively low cost and simplicity. Usually, printed parts have an internal structure (infill) that is not produced with 100% material density. This strategy is adopted to save material and time thanks also to the fact that when a component...
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... is one amongst the most influential parameters in FDM [15,[25][26][27][28], affecting both mechanical resistance and other factors such as dimensional accuracy. From Figure 6, it can be seen how elongation at break (í µí°´!µí°´! ) decreases with higher temperatures, whilst ultimate tensile strength (í µí± " ) and specimen rigidity (í µí°¸) increase. In Table 2 detailed results breakdown is reported, presenting average values with standard deviation (in round brackets). ...
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... is one amongst the most influential parameters in FDM [15,[25][26][27][28], affecting both mechanical resistance and other factors such as dimensional accuracy. From Figure 6, it can be seen how elongation at break (í µí°´!µí°´! ) decreases with higher temperatures, whilst ultimate tensile strength (í µí± " ) and specimen rigidity (í µí°¸) increase. In Table 2 detailed results breakdown is reported, presenting average values with standard deviation (in round brackets). ...
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In an attempt to make Additive Manufacturing more material-efficient, researchers come across the idea of re-enforcing 3D printed objects by infill pattern modification. In line with this concept, this paper introduces a new innovative infill pattern inspired by a variety of strut-base lattice structures that is stronger and more material-efficient...
Citations
... The density of the outer wall is 100% infill. The internal volume is made up of infill of different geometry and density [14,15]. The infill is used to transfer internal stress and support the external walls. ...
... Set infill parameters affect production time and material consumption. [14,15]. ...
... A lot of scientific papers [16][17][18][19][20] present experimental research on the tensile strength of components produced by additive technologies, especially FDM technology. [14,15]. ...
Additive manufacturing (AM) technologies are becoming a global phenomenon in the manufacturing industry. The progressiveness of additive manufacturing lies in its universality. AM makes it possible to produce parts with complex shapes from different materials without any tools, using only one device. Complex and time-consuming production preparation is eliminated by using AM. It is used in a wide range of industries. Although additive manufacturing is a progressive technology, the currently applied conservative approach has significant limits. The presented work focuses on the development of a new methodology for controlling the AM process. This methodology is based on the outputs of the strength simulation of a specific component through the finite element method (FEM) and their implementation in the printing software of the production equipment. The developed algorithm for controlling the AM process consists of a sequence of successive steps. The designed CAD model of the component is subjected to FEM simulation in order to analyze the von Mises stress in the entire volume of the loaded component. Stresses are distributed asymmetrically in the volume of the component due to the shape and nature of the load. The results of the FEM analysis allow the definition of the volumes in the component with different levels of infill geometry and infill density based on different levels of stress. The FEM simulation also serves to define the effective fiber orientation. The goal of implementing FEM simulation into the building structure of the component is to achieve a symmetrical distribution of stresses in the entire volume. Through the symmetry of internal stresses, it is possible to obtain more efficient production with high productivity and component strength. The work also deals with experimental research on the effect of the building structure on flexural strength. The results of FEM simulation and experimental research are integrated into the developed slicer software to design a layering of the model and the setting of technological and material parameters of printing. This progressive approach makes it possible to generate data for 3D printing based on FEM analysis of components to obtain an optimized printed structure of components and optimized technological and material parameters with regard to maximizing the strength of components and minimizing production times and costs.
... Based on a review of the scientific literature, it is possible to conclude that the research so far in the field of mechanical properties of 3D-printed materials (tensile, flexural, and torsional) has gone in four main directions: (1) the influence of the input material's characteristics (type, color, etc.) [14][15][16], (2) the impact of filling design on the mechanical properties [17][18][19][20][21][22][23][24][25], (3) the influence of production process parameters (layer height, air gap, raster width, raster angle, build orientation, number of contours, flour/roof thickness, deposition speed, etc.) [26][27][28][29][30][31][32][33], and (4) the influence of environmental factors (temperature, vibrations, humidity, etc.) [34][35][36]. ...
Polymer materials and composites play a pivotal role in modern industry, prized for their durability, light weight, and resistance to corrosion. This study delves into the effects of mineral engine oil exposure on the mechanical parameters of 3D-printed materials created through fused deposition modeling (FDM). The research scrutinizes prototype materials under diverse environmental conditions, with a particular focus on the tensile parameters. The primary aim is to analyze and compare how mineral engine oil affects the mechanical parameters of four commonly used FDM 3D-printed materials: PLA, PLA+CF composites, PETG, and PETG+CF composites. In the case of the PLA specimens, the tensile strength decreased by approximately 36%, which, considering the 30% infill, remained acceptable. Simultaneously, the nominal strain at the point of breaking increased by 60.92% after 7 days and 47.49% after 30 days, indicating enhanced ductility. Interestingly, the PLA’s Young’s modulus remained unaffected by the oil. The 3D-printed PLA+CF materials exposed to 30 days of mineral engine oil displayed a substantial Young’s modulus increase of over 49.93%. The PETG specimens exhibited intriguing behavior, with a tensile strength decrease of 16.66% after 7 days and 16.85% after 30 days, together with a notable increase in the nominal strain at breaking by 21.34% for 7 days and 14.51% for 30 days, signifying enhanced ductility. In PETG material specimens, the Young’s modulus increased by 55.08% after 7 days and 66.27% after 30 days. The PETG+CF samples initially exhibited increases in tensile strength (1.78%) and nominal strain at breaking (6.08%) after 7 days, but later experienced an 11.75% reduction in the tensile strength after 30 days. This research underscores the critical role of material selection in oil-exposed environments and suggests avenues for future exploration, encompassing microstructural analysis, the long-term impact of oil exposure, and broader considerations related to environmental and oil-specific factors. It contributes to a deeper understanding of the intricate interactions between polymer materials and mineral engine oil, offering valuable insights that can enhance industrial applications.
... FDM (Fused Deposition Modelling) printing technology, also known as FFF (Fused Filament Fabrication), is an extrusion-based additive manufacturing process in which a thermoplastic material as a filament is melted and selectively deposited through a printing nozzle [9,[34][35][36][37][38]. This way, a model according to the computer design is produced layer by layer. ...
This study aims to investigate the adhesion of combining two materials with different properties (PLA-TPU and TPU-PLA) printed in FFF (fused filament fabrication) with post-processing treatments.The scope of the study includes making variants of samples and subjecting them to three different post-printing treatments. After processes, shear tests were conducted to determine the adhesion.The post-printing treatment results in a stronger inter-material bond and increased adhesion strength; the best average shear strength results were achieved for annealing without acetone and for PLA/TPU samples for treatment in cold acetone vapour.In the study, adhesion was considered in the circular pattern of surface development.Reinforcement of the biopolymer broadens the possibilities of using polylactide. Examples of applications include personalised printing items, where the elastomer will strengthen the polylactide.These studies aim to promote the use and expand the possibilities of using PLA biopolymer. The strength properties of printouts from different materials are often insufficient, hence the proposal to use post-printing processing.
... A decrease in mass and material consumption is achieved using an infill pattern. Furthermore, the infill patterns should be selected in relation to the loads applied to the part, aiming to optimize the stress distribution and static/dynamic behavior [1][2][3][4]. ...
... The main properties of the material (according to the manufacturer's specifications) were: density-1.24 g/cm 3 (Table 2) were maintained constant for all three structures. Ultimaker PLA Silver To compare the mechanical behavior of the three structures, the differences in actual volume (reflecting material consumption) were calculated, based on the 3D models from SolidWorks ( Table 1). ...
... The main properties of the material (according to the manufacturer's specifications) were: density-1.24 g/cm 3 (Table 2) were maintained constant for all three structures. The selection of the printing parameters was done in accordance with the manufacturer's recommendations and previous research [16,39]. ...
Additive manufacturing technologies enable the production of components with lightweight cores, by means of infills with various patterns and densities. Together with reduced mass and material consumption, infill geometries must ensure that strength and stiffness conditions are fulfilled. For the proper correlation of the infill type with the loading case of the part, the mechanical behavior of the infill along all three principal axes of inertia has to be known. In this paper, the behavior in symmetric and asymmetric bending of three infill geometries, commonly used in 3D printing processes (honeycomb, grid and triangles) is analyzed. The variations of deflections as a function of force orientation are presented, showing that honeycomb and triangular structures exhibit similar behaviors along the Y and Z principal axes of inertia. Furthermore, the displacements obtained for the three types of structures are compared, in relation to the consumed volume of material. The larger displacements of the grid structure compared to the honeycomb and triangular structures are highlighted.
... Within the context of integrating novel information technologies, 3D printing is a computer-aided manufacturing process in which components are made by filling material in the design space over time. [1][2][3][4][5][6][7][8] Fused Deposition Modelling (FDM) is thought to be environmentally sustainable. 9 It's one of the most popular types of commercial 3D printing technologies. ...
In additive manufacturing, fused deposition modelling (FDM) is one of the most often-used technologies. Polylactic Acid (PLA) is the most frequently applied polymer for prototyping or for real uses. This study mainly focuses on the mechanical properties of PLA parts printed with filament exposed to UV light to mimic the effect of recycled filament. Three radiation periods were studied, respectively, 24 h, 48 h and 72 h. Tensile tests were carried out to characterize the influence of building orientation (On flat/on-edge) and raster angles (0°, 45°, 90°, 0°/90°, −45°/+45°). Failure modes were also discussed. Printed specimens were subjected to water absorption to assess the mechanical properties in real application. Generally with the same raster angle, the interlayer structure of specimens manufactured in on-edge orientation has greater adhesion than the specimens in flat orientation. The results show that mechanical properties are lower in case of flat building orientation and the raster angle has the same trend in both orientations. Elsewhere, edge orientation exhibited lower water absorption thanks to the inwall that protected the printed part. UV radiation enhances the interface between printed layers for the lower period. The mechanical properties were affected by the degradation of the bulk material in the direction of 90°.
... The results have shown that using PLA as a raw material for FDM produced a superior accuracy and increased surface roughness when the part is fabricated with an internal pattern structure compared to a hollow structure. Bergonzi et all investigated the infill influence over FDM produced parts using PLA [6]. The optimum printing temperature has been found to be higher than the filament's manufacturer recommended maximum, being 235°C instead of 230°C. ...
Additive manufacturing (AM) is a process that can achieve many parts with complex features in the production. The most important aspect of AM is that there is no material wastage, which reduces costs. The benefits of AM have been noticed and the process is now being used in many fields like in medicine, in automotive, in aircraft, etc. Additive manufacturing materials can be tested by stretching, Charpy or Izod impact, bending, shearing, etc. For plastics, the most widely used process for impact testing is Izod. Prusa MK3 printer was used for the manufacturing of the specimens from polylactic acid (PLA). The specimens were tested with the CEAST 9050 pendulum impact system, according to the ISO 180:2000 standard. The numerical modeling of the experimental measurements has been done with the ANSYS finite element software's explicit module, called LS-DYNA. A good correlation between the numerical model and experimental tests was observed.
... Additive manufacturing (AM) technologies allow components with adjustable geometry and mechanical properties [4][5][6] that can be used in a wide variety of industry sectors to be obtained [7]. Fused deposition modelling (FDM), also known as fused filament fabrication (FFF), is an AM process based on extrusion, where material as a filament is melted and selectively dispensed through a fine nozzle layer upon layer according to the slice model [8][9][10][11][12][13][14]. ...
A 3D printer in FDM technology allows printing with two nozzles, which creates an opportunity to produce multi-material elements. Printing from two materials requires special consideration of the interface zone generated between their geometrical boundaries. This article aims to present the possibility of printing with PLA and TPU using commercially available filaments and software to obtain the best possible bond strength between two different polymers with respect to printing parameters, surface pattern (due to the material contact surface’s roughness), and the order of layer application. The interaction at the interface of two surfaces of two different filaments (PLA-TPU and TPU-PLA) and six combinations of patterns were tested by printing seven replicas for each. A total of 12 combinations were obtained. By analyzing pairs of samples (the same patterns, different order of materials), the results for the TPU/PLA samples were better or very close to the results for PLA/TPU. The best variants of pattern combinations were distinguished. Well-chosen printing parameters can prevent a drop in parts efficiency compared to component materials (depending on the materials combination).
Predmet doktorske disertacije je teoretsko-eksperimentalno istraživanje uticaja dizajna ispune (eng. infill design) na osobine FDM printanih polimernih materijala sa strukturom ispune. S tim u vezi, jedan od primarnih ciljeva istraživanja je razvoj metodologije ispitivanja s ciljem dobivanja matematskih formulacija (matematskih modela) za procjenu zateznih mehaničkih osobina u zavisnosti od dizajna ispune (oblik, gustina i ugao).
Na osnovu teoretskog istraživanja predstavljen je detaljan pregled dosadašnjih istraživanja na temu uticaja dizajna ispune na osobine FDM printanih polimernih materijala. Dat je pregled materijala za aditivne tehnologije sa fokusom na FDM polimerne materijale. Predstavljeni su fizikalni aspekti pri formiranju FDM printanih polimernih materijala, te su predstavljeni uticajni faktori na osobine istih. Opisani su FDM printani polimerni materijali sa strukturom ispune, te navedene njihove karakteristike. Opisan je način ispitivanja mehaničkih osobina FDM printanih materijala sa i bez strukture ispune, pri čemu su analizirani standardi koji se najčešće koriste pri ispitivanju istih.
U eksperimentalnom dijelu, urađeno je ispitivanje zateznih mehaničkih ispitivanja PLA, Tough PLA, PC i PETG FDM printanih polimernih materijala sa strukturom ispune. Analiziran je uticaj 7 različitih oblika ispune, 4 različite gustine i 4 ugla ispune u odnosu na smjer opterećenja, pri čemu su ukupno analizirana 1344 ispitna uzorka. Prikazani su dijagrami napon-deformacija za svaki materijal prema obliku ispune. Također, rezultati su predstavljeni i uspoređeni kroz histograme, gdje je za svaki oblik ispune prikazan uticaj gustine i ugla ispune na maksimalnu silu 𝐹𝑚 i modul elastičnosti 𝐸. Izvršena je i usporedba mehaničkih osobina samih materijala.
Primjenom dizajna eksperimenta, metodologijom potpunog faktorijalnog dizajna, analiziran je uticaj dizajna ispune na maksimalnu silu 𝐹𝑚 i modul elastičnosti 𝐸 za svaki materijal, te su razvijeni matematski modeli za predviđanje istih. Za ocjenu tačnosti matematskog modela korišteni su koeficijent determinacije 𝑅2 (R-sq), 𝑅2 prilagođeni (R-sq adj) i 𝑅2 predviđeni (R-sq pred). Adekvatnost razvijenih matematskih modela, provjerena je pomoću analize reziduala, gdje je posmatran histogram i grafik normalne vjerovatnoće reziduala. Slaganje eksperimentalnih i modelom predviđenih vrijednosti izvršeno je zaračunavanjem koeficijenta korelacije R. Kako bi se provjerio i procijenio uticaj i značaj faktora (oblik, gustina i ugao ispune), korištena je analiza varijanse (ANOVA). Također, predstavljeni su dijagrami glavnih efekata i interakcija. Primjenom Tukey testa izvršena je analiza višestrukim upoređivanjem srednjih vrijednosti izlaza za sve nivoe faktora. Primjenom 3D dijagrama i dijagrama kontura, grafički je predstavljen zajednički uticaj gustine i ugla ispune na maksimalnu silu 𝐹𝑚 i modul elastičnosti 𝐸. Urađena je i validacija matematskog modela kao i optimizacija maksimalne sile 𝐹𝑚 i modula elastičnosti 𝐸.
Na kraju je urađena tehno-ekonomska analiza primjene strukture ispune kod FDM printanih polimernih materijala. Analiziran je uticaj oblika, gustine i ugla ispune na ukupno vrijeme printanja ispitnog uzorka, količina utrošenog materijala tokom printanja, kao i vrijeme printanja strukture ispune. Zatim je kroz dijagrame predstavljena usporedba izrade proizvoda, u ovom slučaju ispitnog uzorka, sa i bez (100% gustina ispune) primjene strukture ispune. Analizirana je ušteda ukupnog vremena printanja kao i količine potrošenog materijala pri promjeni gustine ispune, kao najutjecajnijeg parametra dizajna ispune na iste.
