Filament Extrusion Research Articles

Energy and Eco-Impact Evaluation of Fused Deposition Modeling and Injection Molding of Polylactic Acid

There is limited knowledge about energy and carbon emission performance comparison between additive fused deposition modeling (FDM) and consolidation plastic injection molding (PIM) forming techniques, despite their recent high industrial applications such as tools and fixtures. In this study, developed empirical models focus on the production phase of the polylactic acid (PLA) thermoplastic polyester life cycle while using FDM and PIM processes to produce American Society for Testing and Materials (ASTM) D638 Type IV dog bone samples to compare their energy consumption and eco-impact. It was established that energy consumption by the FDM layer creation phase dominated the filament extrusion and PLA pellet production phases, with, overwhelmingly, 99% of the total energy consumption in the three production phases combined. During FDM PLA production, about 95.5% of energy consumption was seen during actual FDM part building. This means that the FDM process parameters such as infill percentage, layer thickness, and printing speed can be optimized to significantly improve the energy consumption of the FDM process. Furthermore, plastic injection molding consumed about 38.2% less energy and produced less carbon emissions per one kilogram of PLA formed parts compared to the FDM process. The developed functional unit measurement models can be employed in setting sustainable manufacturing goals for PLA production.

Filament extrusion of bioresorbable PDLGA for additive manufacturing utilising diatom biosilica to inhibit process-induced thermal degradation

Bone scaffolds are often fabricated by initially producing custom-made filaments by twin-screw extruder and subsequently fabricating into 3D scaffolds using fused deposition modelling. This study aims to directly compare the effect of two alternative silica-rich filler materials on the thermo-mechanical properties of such scaffolds after extrusion and printing. Poly (DL-lactide-co-glycolide) (PDLGA) was blended with either 45S5 Bioglass (5 wt %) or Biosilica (1 and 5 wt%) isolated from Cyclotella meneghiniana a freshwater diatom were tested. Diatom-PDLGA was found to have similar mechanical strength and ductility to pure-PDLGA, whereas Bioglass-PDLGA was found induce a more brittle behaviour. Bioglass-PDLGA was also found to have the lowest toughness in terms of energy absorption to failure. The TGA results suggested that significant thermal degradation in both the Bioglass filaments and scaffolds had occurred as a result of processing. However, diatom biosilica was found to inhibit thermal degradation of the PDLGA. Furthermore, evidence suggested the agglomeration of Bioglass particles occurred during processing the Bioglass-PDLGA filaments. Overall, diatom biosilica was found to be a promising candidate as a bone filler additive in 3D printed PDLGA scaffolds, whereas Bioglass caused some potentially detrimental effects on performance.

Exploring the possibilities of FDM filaments comprising natural fiber-reinforced biocomposites for additive manufacturing

<abstract> In recent years, with the recent advancements in the field of additive manufacturing, the use of biobased thermoplastic polymers and their natural fiber-reinforced biocomposite filaments have been rapidly emerging. Compared to their oil-based counterparts, they provide several advantages with their low carbon footprints, ease of reusability and recyclability and abundancy, and comparable price ranges. In consideration of their increasing usage, the present study focused on the development and analysis of biocomposite material blends and filaments by merging state-of-the-art manufacturing and material technologies. A thorough suitability study for fused deposition modeling (FDM), which is used to manufacture samples by depositing the melt layer-by-layer, was carried out. The mechanical, thermal, and microstructural characterization of birch fiber reinforced PLA composite granules, in-house extruded filaments, and printed specimens were investigated. The results demonstrated the printability of biocomposite filaments. However, it was also concluded that the parameters still need to be optimized for generic and flawless filament extrusion and printing processes. Thus, minimal labor and end-products with better strength and resolutions can be achieved. </abstract>

Fabrication of suspended uniform polymer microfibers by FDM 3D printing

In this study, we propose a novel method to fabricate suspended polymer microfibers with the principle of liquid bridge in the range of 25–180μm in thickness and centimeter range in length by stretching viscoelastic fluid, employing a commercial fused deposition modeling (FDM) 3D printer and a PLA (polylactic acid) 3D printing filament. Highly uniform thickness of microfibers (CV<5%) is also achievable in various sizes by our proposed method in ranges of 25–30μm and 75–130μm. For the thickness control and the uniformity of the thickness, we investigate three main printing control factors (filament extrusion volume, printing speed, and gaps between printing nozzle and printing bed) through experiment. The observation from the experiment concludes that the filament extrusion volume is the most dominant factor to rule the thickness of the suspended polymer microfiber, and the printing speed is the following determinant factor. The uniformity of the thickness is maintained with a lower extrusion volume and a higher printing speed, and it is concluded that such a printing setting makes microfibers thinner due to smaller viscoelastic internal compressing force along the microfiber. Additionally, we analyze a relation of the three printing parameters to estimate the thickness of the microfiber by FDM 3D printing.

Recipe Development and Mechanical Characterization of Carbon Fibre Reinforced Recycled Polypropylene 3D Printing Filament

Recycled polypropylene filaments for fused filament fabrication were investigated with and without 14 wt% short fibre carbon reinforcements. The microstructure and mechanical properties of the filaments and 3D printed specimens were characterized using scanning electron microscopy and standard tensile testing. It was observed that recycled polypropylene filaments with 14 wt% short carbon fibre reinforcement contained pores that were dispersed throughout the microstructure of the filament. A two-stage filament extrusion process was observed to improve the spatial distribution of carbon fibre reinforcement but did not reduce the pores. Recycled polypropylene filaments without reinforcement extruded at high screw speeds above 20 rpm contained a centreline cavity but no spatially distributed pores. However, this cavity is eliminated when extrusion is carried out at screw speeds below 20 rpm. For 3D printed specimens, interlayer cavities were observed larger for specimens printed from 14 wt% carbon fibre reinforced recycled polypropylene than those printed from unreinforced filaments. The values of tensile strength for the filaments were 21.82 MPa and 24.22 MPa, which reduced to 19.72 MPa and 22.70 MPa, respectively, for 3D printed samples using the filaments. Likewise, the young’s modulus of the filaments was 1208.6 MPa and 1412.7 MPa, which reduced to 961.5 MPa and 1352.3 MPa, respectively, for the 3D printed samples. The percentage elongation at failure for the recycled polypropylene filament was 9.83% but reduced to 3.84% for the samples printed with 14 wt% carbon fiber reinforced polypropylene filaments whose elongation to failure was 6.58%. The SEM observations on the fractured tensile test samples showed interlayer gaps between the printed and the adjacent raster layers. These gaps accounted for the reduction in the mechanical properties of the printed parts.

Fabrication of a 3D-Printed Porous Junction for Ag|AgCl|gel-KCl Reference Electrode

Fused filament fabrication (FFF) is a 3D printing method that is attracting increased interest in the development of miniaturized electrochemical sensor systems due to its versatility, low cost, reproducibility, and capability for rapid prototyping. A key component of miniaturized electrochemical systems is the reference electrode (RE). However, reports of the fabrication of a true 3D-printed RE that exhibits stability to variations in the sample matrix remain limited. In this work, we report the development and characterization of a 3D-printed Ag|AgCl|gel-KCl reference electrode (3D-RE). The RE was constructed using a Ag|AgCl wire and agar-KCl layer housed in a watertight 3D-printed acrylonitrile butadiene styrene (ABS) casing. The novel feature of our electrode is a 3D-printed porous junction that protects the gel electrolyte layer from chloride ion leakage and test sample contamination while maintaining electrical contact with the sample solution. By tuning the 3D printing filament extrusion ratio (k), the porosity of the junction was adjusted to balance the reference electrode potential stability and impedance. The resulting 3D-RE demonstrated a stable potential, with a potential drift of 4.55 ± 0.46 mV over a 12-h period of continuous immersion in 0.1 M KCl, and a low impedance of 0.50 ± 0.11 kΩ. The 3D-RE was also insensitive to variations in the sample matrix and maintained a stable potential for at least 30 days under proper storage in 3 M KCl. We demonstrate the application of this 3D-RE in cyclic voltammetry and in pH sensing coupled with electrodeposited iridium oxide on a gold electrode. Our method offers a viable strategy for 3D printing a customizable true reference electrode that can be readily fabricated on demand and integrated into 3D-printed miniaturized electrochemical sensor systems.

Poly(vinylidene fluoride)/thermoplastic polyurethane flexible and 3D printable conductive composites

AbstractThis work focus on the development of polymeric blends to produce multifunctional materials for 3D printing with enhanced electrical and mechanical properties. In this context, flexible and highly conductive materials comprising poly(vinylidene fluoride)/thermoplastic polyurethane (PVDF/TPU) filled with carbon black‐polypyrrole (CB‐PPy) were prepared by compression molding, filament extrusion and fused filament fabrication. In order to achieve an optimal compromise between electrical conductivity, mechanical properties and printability, blends composition was optimized and different CB‐PPy content were added. Overall, the electrical conductivities of PVDF/TPU 50/50 vol% co‐continuous blend were higher than those found for PVDF/TPU 50/50 wt% (i.e., 38/62 vol%) composites at same filler content. PVDF/TPU/CB‐PPy 3D printed samples with 6.77 vol% filler fraction presented electrical conductivity of 4.14 S m−1 and elastic modulus, elongation at break and maximum tensile stress of 0.43 GPa, 10.3% and 10.0 MPa, respectively. These results highlight that PVDF/TPU/CB‐PPy composites are promising materials for technological applications.

Finite element analysis of fused filament extrusion build part using different build orientation

3D printing has converged the whole manufacturing process in this competitive world of technology. Replacement of subtractive to additive principle introduced trouble-free production of complex shapes with least wastage of material. Fused Filament Extrusion (FFE) is a widely used 3D printing technique. But strength of the 3D printed part was always be the question for critical application. Build orientation is one of the listed parameters of 3D printing process which plays a vital role on the fracture resistance of the 3D printed part. In order to understand the fracture resistance numerically, Finite Element Analysis has been performed on the CT-specimen. In the present work, Acrylonitrile Butadiene Styrene (ABS) material has been considered. The CT-specimen is loaded in the crack opening mode with displacement-controlled loading. Orthotropic behaviour was used for material definition. The value of load and Fracture toughness in terms of J-integral is estimated at the crack initiation. It was observed that the value of J-integral increased considerably with the increase in build orientation from 0 to 90 degrees.

Impact of processing conditions and sizing on the thermomechanical and morphological properties of polypropylene/carbon fiber composites fabricated by material extrusion additive manufacturing

AbstractFor the 3D printed composites, fiber alignment is affected by the direction of melt‐flow during extrusion of filaments and subsequently through the printing nozzle. The resulting fibers orientation and the fiber‐matrix compatibility have a direct correlation with mechanical properties. This study investigates the impact of processing conditions on the state of the carbon fiber types and their orientation on the mechanical properties of 3D‐printed composites. Short and long carbon fibers were used as starting reinforcing materials, and the state of fibers at the beginning and on the printed parts were evaluated. Strong anisotropy in terms of mechanical properties (flexural and impact properties) was observed for the samples printed with different printing orientations. Interestingly, the number of voids in the printed composites was found to be correlated with the fiber types. The present work provides a step towards the optimization of tailored composite properties by additive manufacturing.

Tensile properties of 3D-printed wood-filled PLA materials using poplar trees

Fabrication of renewable materials through additive manufacturing using wood-filled polylactic acid (PLA) is an emerging field of study. The variability in the tensile properties of 3D-printed materials due to the variability in woody biomass properties has not been studied. Biomass size reduction, filament extrusion, and 3D-printing methods were investigated to determine the conditions that resulted in consistent printing. Using 20% ball-milled poplar reinforcement in PLA, 210 °C filament extrusion temperature and 230 °C printing temperature were found to be the best conditions. Subsequently, seventy poplar samples from a common garden were used to test the tensile properties of the printed materials. The median tensile strength at yield was 50 MPa, with 5–95 percentiles ranged in 37–54 MPa. Strain% at break had a median value of 2.1%, and 5–95 percentiles were 1.7–2.7%. The median Young's modulus was 3.65 GPa, and 5–95 percentiles ranged in 2.9–4.1 GPa. Biomass density was correlated to composite density. Median particle size of ball-milled poplar was negatively correlated with tensile strength. Composite density affected tensile strength of the composite. β-glycosidic bond of polysaccharides in biomass affected Young's modulus of the composite. These data show that genotypic variation among Populus trichocarpa have substantial effect on tensile properties of 3D printed PLA-poplar materials.

Bending performance enhancement by nanoparticles for FFF 3D printed nylon and nylon/Kevlar composites

Fused filament fabrication (FFF) has been a major 3D printing technique for making thermoplastic products for decades. However, FFF printing for thermoplastic composites with aligned continuous fibers has been reported with limited success for only several years. In this study, we introduce an enhanced FFF-based approach by incorporating nanoparticles to the thermoplastic composites with continuous fibers. Our investigation focuses on the bending properties of FFF-printed fiber reinforced composites with and without nanoparticles. With Nylon 6 (PA 6) being the matrix material, nanocomposite filaments are obtained by adding carbon nanotubes (CNTs), graphene nano platelets (GNPs), or amino (NH2-) functionalized GNPs. Various PA 6 matrix nanocomposite filaments are prepared through mixing and filament extrusion process. The nanocomposite filaments are then 3D printed with or without continuous Kevlar fiber prepreg filaments. For 3D printed pure PA 6, the addition of 1 wt% GNP-NH2 increases the flexural strength and bending modulus by 334% and 315%, respectively. For 3D printed PA 6/Kevlar composite, the addition of 1 wt% GNP-NH2 increases the flexural strength and bending modulus by 195% and 35%, respectively. However, the addition of CNTs or GNPs (up to 1 wt%) is less effective as compared with GNP-NH2. The underlying mechanisms are discussed based on the matrix/fiber interfacial analysis.

Three-Dimensional Printed Lightweight Composite Foams.

The goal of this paper is to enable three-dimensional (3D) printed lightweight composite foams by blending hollow glass microballoons (GMBs) with high density polyethylene (HDPE). To that end, lightweight feedstock for printing syntactic foam composites is developed. The blend for this is prepared by varying the GMB content (20, 40, and 60 volume %) in HDPE for filament extrusion, which is subsequently used for 3D printing. The rheological properties and the melt flow index (MFI) of blends are investigated for identifying suitable printing parameters. It is observed that the storage and loss modulus, as well as complex viscosity, increase with increasing GMB content, whereas MFI decreases. Further, the coefficient of thermal expansion of HDPE and foam filaments decreases with increasing GMB content, thereby lowering the thermal stresses in prints, which promotes the reduction in warpage. The mechanical properties of filaments are determined by subjecting them to tensile tests, whereas 3D printed samples are tested under tensile and flexure tests. The tensile modulus of the filament increases with increasing GMB content (8–47%) as compared to HDPE and exhibit comparable filament strength. 3D printed foams show a higher specific tensile and flexural modulus as compared to neat HDPE, making them suitable candidate materials for weight-sensitive applications. HDPE having 60% by volume GMB exhibited the highest modulus and is 48.02% higher than the printed HDPE. Finally, the property map reveals a higher modulus and comparable strength against injection- and compression-molded foams. Printed foam registered 1.8 times higher modulus than the molded samples. Hence, 3D printed foams have the potential for replacing components processed through conventional manufacturing processes that have limitations on geometrically complex designs, lead time, and associated costs.

Analysis of Correlation Between Contrast and Component of Polylatic Acid Composite for Fused Deposition Modeling 3D Printing.

Additive manufacturing or three-dimensional (3D) printing is considered a disruptive technology for producing components with topologically optimized complex geometries as well as functionalities that are not achievable by traditional methods. 3D printing is expected to revolutionize the manufacturing of components. While several 3D printing systems are available, printing based on fused-deposition modeling (FDM) using thermoplastics is particularly widespread because of the simplicity and potential applicability of the method. In this study, we report the analysis of correlation between contrast and component of polylactic acid (PLA) based composite for FDM 3D printing. The pre-fabricated white composite and black composite were mixed in the fraction of 100:0, 90:10, 75:25, 50:50, 25:75, and 0:100% (v/v) and the obtained mixture was extruded using HX-35 3D filament extrusion line. The samples in different contrast were printed in disk like shape, and the gray scale filaments and 3D printed samples were measured the morphology and components using a field emission scanning electron microscope and energy dispersive X-ray spectroscopy. The CIE-lab values of the samples were measured using a colorimeter and the correlation between CIE-lab values and the components were analyzed. Although the component of Ti was linearly increased, the CIE-lab values show a clear exponential increase by increasing the white composite.

Innovative processing route combining fused deposition modelling and laser writing for the manufacturing of multifunctional polyamide/carbon fiber composites

An innovative manufacturing method, based on Fused Deposition Modelling (FDM) and Laser Writing (LW) technologies, was developed to integrate electrically conductive tracks within high strength 3D printed parts. Carbon fibers reinforced polyamide composites were processed by FDM according to three different printing architectures by varying the raster angle in the layer sequence. Laser writing was then performed to obtain conductive tracks on the surface of the printed parts. The process-structure-property relationship of components before and after the writing of conductive tracks was investigated. The tensile behaviour and the track resistance of samples were correlated to the direction of filament extrusion within the layers, and consequently to fibers orientation. Tracks showing good aesthetic quality and the lowest electrical resistance were obtained on samples with [±45] architecture. These tracks displayed the lowest electrical resistance ever reached by laser writing on metal-free polymer composites (0.008 kΩ/cm). Samples with [±45] architecture also showed high strength (72.9 MPa) and stiffness (7.7 GPa). The integration of FDM and LW emerges as a new approach to transform the surface of high strength polymer composites parts into a highly valuable system. These multifunctional components can find applications in several industrial fields such as automotive, aeronautics, and appliances.

Computed tomography evaluation of the porosity and fiber orientation in a short carbon fiber material extrusion filament and part

The computed tomography (CT) evaluation of the material extrusion (MEX) of a short carbon fiber (SCF) Nylon-12 filament and part is presented. CT, a non-destructive testing method, was used to quantify the internal structure of specimens into three phases: pore, Nylon, and SCF. The intensity histograms from the CT data were fit using a mixed skew-Gaussian distribution (MSGD) algorithm to segment the CT image into phases. Thresholded images were used to isolate pores in the CT image to determine pore volume and distribution within both the MEX SCF filament and part. The phase volume percentages of the MEX SCF filament were found to be 1.6% pore, 62.2% Nylon, and 36.2% SCF. The volume of most pores within the filament were found to be under 100 μm3. The highest frequency of pores was located near the outside of the filament, but the large pores were located near the center of the filament. This result indicates that the thermoplastic filament extrusion process likely entraps large bubbles in the center of filament or causes large thermal gradients and residual stresses that induce voids during post-extrusion cooling. MSGD analysis of sections of the MEX SCF part estimated phase volume percentages to be 9.8% pore, 59.6% Nylon, and 30.9% SCF. This analysis showed a more than 8% increase in porosity from the MEX SCF filament to the part. For the MEX SCF part, the average pore area was found to be highest (>250 μm2) at the bottom of the layer and smallest (<100 μm2) at the top of the layer, which could be explained by a large temperature gradient between and contractile thermal stresses inside the layer that cause the thermoplastic to shrink into a smaller volume allowing the voids to grow during deposition. A qualitative analysis of fiber orientation conducted on the SCF filament indicated that the SCFs maintain their orientation from filament to part except in the intersection zone of rasters.

A rheology-based quasi-static shape retention model for digitally fabricated concrete

The shape retention capability of an extruded filament is of cardinal importance for quality 3D printed concrete elements. Not only is it a prerequisite for surface aesthetics, but it also contributes towards buildability. Optimisation of filament layer height allows for construction time and cost saving possibilities. This research develops the theoretical framework for an analytical shape retention model that predicts the maximum stable filament layer height at which no plastic yielding occurs, based only on the rheology of a material. The Mohr-Coulomb failure criterion is employed and the model simplified by conservatively negating the effect of interparticle friction. A model is also developed that determines whether sufficient friction is present to induce confinement within a filament layer. An experimental verification process via filament extrusion confirms the applicability of the model. A 6.7% difference in stable filament layer height is obtained by comparison with a finite element analysis, proffering as numerical verification for the model.

Influence of Manufacturing Parameters and Post Processing on the Electrical Conductivity of Extrusion-Based 3D Printed Nanocomposite Parts.

The influence of manufacturing parameters of filament extrusion and extrusion-based Additive Manufacturing (AM), as well as different post processing techniques, on the electrical conductivity of 3D printed parts of graphene nanoplatelets (GNP)-reinforced acrylonitrile butadiene styrene (ABS) has been analyzed. The key role of the manufacturing parameters to obtain electrically conductive filaments and 3D printed parts has been demonstrated. Results have shown that an increase in extrusion speed, as well as lower land lengths, induces higher extrudate swelling, with the consequent reduction of the electrical conductivity. Additionally, filaments with lower diameter values, which result in a higher surface-to-cross-section ratio, have considerably lower electrical conductivities. These factors tune the values of the volume and surface electrical conductivity between 10−4–100 S/m and 10−8–10−3 S/sq, respectively. The volume and surface electrical conductivity considerably diminished after 3D printing. They increased when using higher printing layer thickness and width and were ranging between 10−7–10−4 S/m and 10−8–10−5 S/sq, respectively. This is attributed to the higher cross section area of the individual printed lines. The effect of different post processing (acetone vapor polishing, plasma and neosanding, which is a novel finishing process) on 3D printed parts in morphology and surface electrical conductivity was also analyzed.

3D Printing of ABS Barium Ferrite Composites.

In this work, a process for the realization of new polymer matrix composites with nanosized barium ferrite (BaFe12O19) as ferrimagnetic filler, acryl butadiene styrene (ABS) as polymer matrix and an extrusion-based method, namely fused filament fabrication (FFF), as 3D printing method will be described comprehensively. The whole process consists of the individual steps material compounding, rheological testing, filament extrusion, 3D-printing via FFF and finally a widespread specimen characterization regarding to appearance, mechanical properties like tensile and bending behavior as well as the aspired magnetic properties. Increasing ferrite amounts up to 40 vol.% (equal 76 wt.%) cause a reduction of the ultimate stress and an increase of the magnetic polarization as well as of the energy product (BH)max in comparison to the pure polymer matrix. In addition, an extensive discussion of typical printing defects and their consequences on the device properties will be undertaken.

Technical Note: Accurate replication of soft and bone tissues with 3D printing.

The fabrication of a realistic patient-specific skull phantom employing for the first time a new filament extrusion rate method, for the accurate replication of soft and bone tissues both in Hounsfield Units (HU) range and in texture. An in-house developed software was used for the fabrication of the phantom taking into account all the HU of a patient's Computed Tomography (CT) images, replicating the organs voxel-by-voxel without the need of a uniform three-dimensional printing pattern. Two commercially available materials were used; the polylactic acid (PLA) filament for the soft tissues, and a mixture of 50% of PLA and 50% of gravimetric powdered stone for the bone tissues. Additionally, a layer of small amounts of PLA were also extruded on the fabricated bones. The replicated anatomy of the phantom was very close to the patient's one, achieving a similar range of HU without creating any air gaps and variations on the replicated HU, which are the main artifacts observed when a standard infill density and pattern is employed. The maximum measured HU values of the replicated bone tissues were at about 900. The results indicated an accurate replication of the soft tissues HU, and a significant improvement of the bone tissue HU replication. Further investigation on materials of high density in conjunction with the filament extrusion rate method may provide custom-made realistic phantoms for diagnostic and lower energy radiation such as in superficial, orthovoltage, and electron beam radiotherapy.

Thermo-Mechanical analysis of fused filament fabrication process

Manufacturing industry has been revolutionized by 3D printing or Additive Manufacturing (AM) processes introduced in the late 1980s. Subsequent to intensive research, the technology is even accessed by hobbyists. A layer-by-layer deposition of a material produces a prototype in the commercialized 3-dimensional (3D) printing techniques. Among the 3D printing processes, Fused Filament Fabrication (FFF) or Fused Deposition Modelling (FDM) process is the commonly used process for prototyping, manufacturing functional parts, etc. The process involves the extrusion of a molten polymer filament sequentially through a heated nozzle in the required pattern on to a platform. The FDM process primarily depends on the thermal gradient as the deposited molten material cools, solidifies and bonds with the previous layer. This temperature gradient greatly affects the produced parts microstructure and in turn the macrostructure of the final part. Numerous attempts to experimentally characterize the thermal and mechanical properties of structures fabricated with FDM have been reported in the literature. However, few attempts have been made with 2D models to predict the thermal and mechanical behaviour of the FDM printed components. In this study, a 3D thermo-mechanical model has been developed using ANSYS® workbench using the element birth and death effect. The temperature evolution, maximum principal stress and the deformation due to the thermal gradient were calculated using the developed model. The developed Finite Element Analysis (FEA) model was tested with properties of Poly-Lactic Acid (PLA) material. Through the analysis, it was shown that the model can be used as a predictive tool to understand the thermo-mechanical behaviour of FDM printed parts and also the modelling method used has a great influence on the thermal gradient of the printed parts.