Material and process parameter optimization for dimensional accuracy in Fused Deposition Modeling 3D printing

Commercial and industrial use of 3D printing has swiftly taken off as a versatile and effective method of manufacturing on both a small and large scale. Despite being adaptable, the procedure currently works with a restricted number of materials, mostly thermoplastic polymers. 3D printing fused deposition modeling (FDM) provides opportunities to produce complex components relatively quickly in small batch with a high degree of flexibility for both manufacturer and researcher. Process parameters in FDM like infill pattern, infill density, printing speed, raster angle influences the mechanical properties of a printed parts. In this research study, a novel approach on the internal structure of 3D printed parts say combined infill pattern (Triangles & Octet) on a single part has been introduced and mechanical properties like tensile test, flexural strength, compression strength and hardness were measured. Specimens were printed in Acrylonitrile butadiene styrene (ABS) as per ASTM standards by FDM technology with different infill densities of 60%, 80% and 100% by XY build orientation. SEM analysis was made to analyze the morphological and inter bonding of different infill patterns. The results show that mechanical performance was inflated by an increase in infill density.

Abstract. Mechanical parts used in industrial applications should be able to comply not only with rigorous requirements regarding dimensional accuracy and surface quality, but also possess adequate mechanical strength in order to achieve a long service life. Additive manufacturing (AM) processes are considered nowadays an alternative way to produce high-performing parts with complex geometries and different types of materials with high efficiency. Especially in the case of polymers, Fused Filament Fabrication (FFF) is a well-established choice for creating high quality parts at an affordable cost when optimal parameters are used for the printing process. Although a lot of studies have been carried out in order to optimize the parameters of FFF process for the increase of individual mechanical properties, often neglecting the effect of infill density on these properties, it is proposed that the use of reduced mechanical properties, by normalizing them by part weight, can provide more generalized findings and deeper insight into the correlations between process parameters and mechanical behavior. Thus, in the present work, compression test specimens were fabricated by FFF technique under various infill density and layer height values for three different infill patterns, and the fundamental compressive properties such as Young’s Modulus, strength and absorbed energy were determined. After statistical analysis was carried out, the role of each parameter on the improvement of reduced mechanical properties was identified.

3D printing provides new opportunities to create devices used during radiotherapy treatments, yet little is known about the effect process parameters play on the proposed devices. This study investigates the combined influence of infill pattern, infill density and print orientation on surface dose, as well as on the mechanical properties of 3D printed samples, identifying the optimal infill patterns for use in radiotherapy devices including immobilisation. Fused deposition modelling (FDM) was used to produce sixty samples in two orientations for surface dose measurement, utilising ten different infill patterns. Surface dose testing was performed using a Varian Trubeam linear accelerator with a 6 MV photon beam. A further one hundred and twenty tensile test samples, designed according to ASTM D638 type I standards, were evaluated using a 50 KN Instron 5969. On average, horizontally printed samples had a lower surface dose measurement compared to the vertically orientated samples, with the Stars infill pattern recording the lowest surface dose values in the horizontal orientation, while the Hilbert Curve recorded the lowest surface dose in the edge orientation. Tensile tests revealed the 3D Honeycomb infill pattern to have the highest ultimate tensile strength (UTS) in both horizontal and edge orientations. Overall, the Stars infill pattern exhibited the optimal balance of low surface dose and above average UTS. This study shows how infill patterns can significantly affect dosimetry and mechanical performance of 3D printed radiotherapy devices, and the data can be used by design engineers, clinicians and medical physicists to select the appropriate infill pattern, density and print orientation based on the functional requirements of a radiotherapy device.

Warping remains a critical challenge in fused deposition modeling (FDM) of thermoplastic composites, leading to dimensional inaccuracies and compromised mechanical properties in printed parts. Existing studies have predominantly examined individual factors that affect warpage, such as infill specifications and printing orientation, without a comprehensive assessment of their combined effects. This study addresses this gap by employing a transient thermomechanical simulation approach in Digimat-AM, which integrates material crystallinity evolution, fiber orientation effects, and toolpath-dependent thermal history to enhance warpage prediction accuracy. A short carbon fiber-reinforced polyamide 12 composite was selected as the material system due to its complex thermal behavior, including the negative thermal expansion coefficient of carbon fibers. An unmanned aerial vehicle (UAV) camera holder was used as a case study, where the effects of the infill density, the infill pattern, the printing orientation, and the raster angle on warpage and mechanical performance were systematically analyzed. The high-fidelity simulation method in Digimat-AM was utilized to predict warpage, while experimental validation was performed through tensile and bending tests. Analysis of variance was applied to optimize the process parameters. The results demonstrated that a 90% infill density, a triangular infill pattern, a flat printing orientation, and a 90° raster angle significantly reduced warpage, achieving a deviation angle of as low as 0.04°. Furthermore, the combination of 90% infill density, concentric infill pattern and 90° raster angle improved tensile strength (45.58 MPa) and stiffness (2.57 GPa), confirming improved mechanical integrity.

Fused deposition modeling (FDM) is an additive manufacturing process that builds parts layer by layer, selectively depositing melted material in a predetermined path. Two of the principal 3D-print settings that can be modified with FDM are infill density and infill pattern. This project examined the impact of both of these settings on the stiffness of beams printed using FDM. To obtain stiffness values, an accelerometer connected to an oscilloscope was first attached to beams before flicking them in order to determine their resonant frequencies. These data points, along with length, thickness, and density measurements, were then used to calculate each beam's stiffness using Euler–Bernoulli beam theory. An analysis of the results showed that both infill density and infill pattern had a significant impact on the stiffness of beams, suggesting that these print settings are important factors to keep in mind when designing parts to be 3D-printed using FDM.

Additive manufacturing such as 3D printing is considered as a highly convenient manufacturing process since it enables to create any 3D objects. It is known that different materials, printing techniques, and printing parameters are affecting the mechanical properties of the printed objects. However, studies on the mechanical properties of the 3D printed structure are still limited. In this work, investigation of the relationship between two printing parameters, i.e. infill pattern and infill density were conducted on the Polylactic Acid (PLA) material. Three infill densities, 25%, 50%, and 75%, and three infill patterns, grid, tri-hexagon, and concentric, were chosen. The tensile test, ASTM D638, was employed to obtain the material properties based on these two printing parameters. An open-source 3D printing slicer software, Cura, was used to manufacture the tensile specimens. The Young’s modulus, yield strength, and ultimate strength were recorded and examined. The results showed that the tensile properties increase as infill density increases. Of the three-printing pattern, the concentric has the highest values of tensile properties regardless of the infill densities. This finding can be used as a reference for creating a finite element model (FEM) as well as predicting the optimum tensile properties with respect to the printing parameters.

The advent of additive manufacturing has revolutionized the prototyping, design, and manufacturing of new and innovative products. Through the use of Fused Deposition Modeling (FDM), parts can be manufactured using different sparse infill percentages (the percentage of void space within a printed object) and sparse infill patterns (the lattice structure of material within the object). Through the manipulation of these variables, the same material and part can have different compressive and flexural properties. In addition to sparse infill, the thermoplastics used in fused deposition modeling can be reinforced with carbon fiber strands to create a printable composite material capable of strengthening and stiffening parts without increasing the amount of material used. This experiment evaluated the yield stress performance of 3DXTech’s CarbonX PETG+CF filament printed at varying infill densities and infill patterns in hopes of characterizing the minimum structural properties of commonly used lattice structures. The infill patterns were evaluated at 15%, 35%, 50%, and 75% along with a baseline 100% infill with no internal pattern. The two-dimensional infill patterns (infill patterns that do not vary along the z-axis) rectilinear and triangles along with the three-dimensional infill patterns (infill patterns that vary along the z-axis) cubic, gyroid, and 3D honeycomb were tested on the surface perpendicular to the print orientation in order to test the minimum compressive strength of each specimen. All test specimens used were derived from the same STL document and manufactured by Bambo Lab’s X1 Carbon at a resolution of 0.2mm with a nozzle temperature of 260 oC, and the printer was programmed using the g-code created by Bambu Lab’s Bambu Studio slicing software. For each infill density and infill pattern, four test specimens were tested to failure using the Shimadzu Autograph AGX-V2 and its associated software. The yield strength, absolute strength, and stress vs. strain graph of each specimen were derived from the data collected along with photography and projectional radiography of the failure mode. The findings of this research can be summarized as three-dimensional infill patterns being characterized as having larger yield stresses than two dimensional infill patterns along their weakest face, increasing infill density universally increases the yield stress of the object, and objects of higher infill densities buckle at the middle of the specimen, acting as uniform bodies, while lower infill densities tend to buckle at the top and bottom of the specimen. More research is needed to further characterize the effects of stress on PETG-CF lattice structures, but this research can be used to guide the selection of print parameters depending on expected compressive loads.

Fused filament fabrication is a rapidly growing 3D printing technique with the ability to produce functional components with complex shapes. The mechanical characteristics of 3D-printed parts are significantly influenced by various process parameters such as layer thickness, infill density, and nozzle temperature, which can influence part's parameters in conflicting ways. This research focuses on identifying the optimum settings for fused filament fabrication of acrylonitrile butadiene styrene. Specifically, the dimensional deviations, mechanical and abrasive wear properties of printed specimens are investigated. Experiments were designed using the Taguchi method with an L9 orthogonal array, to vary the three factors systematically. The results were analysed using analysis of variance, the Taguchi signal-to-noise ratio, and the regression analysis, with multi-response optimisation performed via desirability function analysis. The optimal balance of all three properties was achieved with infill density = 23%, layer thickness = 0.25 mm, and nozzle temperature = 240°C. This work provides a systematic, statistically validated method for multi-criteria optimisation in fused filament fabrication, offering practical guidance for producing acrylonitrile butadiene styrene components that meet multiple performance requirements simultaneously.

Recently, there is a growing demand towards adopting 3D printing technology in various sectors due to its potential merits. The mechanical properties and surface quality of the final product are influenced by the process parameters. Therefore, this study aims to optimize the infill density and pattern beside printing speed and temperature to achieve optimum mechanical properties and surface characteristics of PLA+ 3D-printed material. The Taguchi method was applied with L9 array, and tensile and surface roughness tests were carried out to evaluate the performance of specimens in terms of the obtained ultimate tensile strength, Young’s modulus, tensile strain (%), and surface roughness. The selected parameters with their levels were as follows: printing temperature (205, 215, and 225°C), printing speed (20, 50, and 80 mm/s), infill density (30%, 60%, and 90%), and infill pattern (triangle, cubic, and concentric). The findings revealed the significant impact of the infill density followed by the infill pattern on the mechanical and surface performances of the PLA+ material. From the other side, the Taguchi method was integrated with grey relational analysis (GRA) as a multiobjective optimization to find out the optimum mechanical properties and surface characteristics of the 3D-printed PLA+ part. Accordingly, 215°C, 50 mm/s, 90%, and triangle pattern achieved optimum mechanical properties (24 MPa, 3.14 GPa, and 13.72%) and surface roughness (3.21 µm).

This study focuses on the investigation of infill patterns and their influence on the mechanical behavior of sandwich structures fabricated using the Fused Deposition Modeling (FDM) technique. Polylactic Acid (PLA) was chosen as the primary material, known for its favorable mechanical properties and biodegradability. Six different infill patterns, including Cubic, Line, Triangular, Trihexagonal, Octet, and Gyroid, were employed to fabricate sandwich structures with varying infill densities (20%, 30%, and 40%). The samples were subjected to edgewise compressive strength tests, and the force-displacement curves were analyzed to evaluate the performance of the structures. The results revealed that the Cubic infill pattern exhibited superior strength in all infill densities, while other patterns showed variations in performance. Moreover, the analysis of damage types indicated different failure modes, such as core shear and facesheet buckling, depending on the infill pattern and density. These findings contribute to understanding the role of infill patterns in enhancing the mechanical properties of sandwich structures fabricated via FDM.

Effect on infill density on mechanical properties of PETG part fabricated by fused deposition modelling

The study herein combines the use of fused filament fabrication (FFF) with finite element analysis (FEA) to enhance the understanding of certain manufacturing parameters (i.e. material, infill density, infill pattern, and outer vertical shell) in the design process of a lumbar fusion cage. Three FFF materials with distinct mechanical properties namely polycarbonate (PC), acrylonitrile butadiene styrene (ABS), and polylactic acid (PLA) were tested. Three infill densities (i.e. 25%, 50%, 75%) were investigated along with two different infill patterns (i.e. rectangular and honeycomb). Compressive modulus and compressive yield strength values obtained from standard mechanical analysis were used as input for FEA to assess numerically the mechanical performance of a lumbar fusion cage under physiological static loading. The findings suggest that both infill density and infill pattern influence the quality of the finished part in terms of both printing accuracy and mechanical response. FEA results indicate that both PC and ABS can be safely adopted to fabricate a porous lumbar cage with a 50% honeycomb infill density and a honeycomb infill pattern. This paper demonstrates that 3D printing assisted FEA can be used to predict the performance of a lumbar cage design with varying manufacturing parameters and potentially reduce product design and development time.

Fused deposition modelling (FDM) is one of the most promising and widely used additive manufacturing (AM) technologies. FDM is commonly used to fabricate simple to complex 3D parts from polymeric materials. Different 3D-printed polymeric components manufactured using FDM technology exhibit various mechanical and load-bearing properties. They are utilized in various industries, particularly the medical industry, for load-bearing applications in bio-implants. Therefore, it is crucial to understand the mechanical characteristics, especially the fatigue behaviour, of these 3D-printed parts under cyclic loadings. This paper focuses on the dynamic behaviour of 3D-printed polymeric parts produced through the FDM process and under different loading modes. First, the FDM mechanism, the various polymeric materials used in FDM, and the effective FDM parameters are briefly introduced. Then, the paper comprehensively covers one of the most important mechanical characteristics of 3D-printed parts for load-bearing applications: their fatigue life under different printing conditions and cyclic loadings. The most influential factors on the fatigue behaviour of polymers include the type of polymeric material, surrounding environmental conditions, cyclic loading conditions, the type of testing specimen, and the FDM printing parameters (such as raster angle, infill density, nozzle diameter, and nozzle temperature). In addition to the anisotropic behaviour reported by various studies on 3D-printed parts using FDM, it has been concluded that the layered structure (with a large number of interfaces between the raster) and the presence of microholes are two factors that weaken the fatigue strength of 3D-printed structures compared to other fabrication processes. These conditions can be exacerbated by choosing inappropriate printing parameters, and often, the failure mechanism in 3D-printed parts fabricated with FDM is delamination.

The increasing interest in sustainable materials has led to the development of bio-based composites for additive manufacturing applications. This study aimed to investigate the influence of key printing parameters and new-generation infill patterns together on the maximum compressive force of PLA-wood bio-composites produced by Material Extrusion. By optimizing this material, low-cost wood-like products can be produced. New-generation 3D infill patterns (octet, cubic-subdivision, and lightning which is a biomimetic infill pattern) infill densities, printing temperatures, and layer heights were selected as variables/factors, and the Taguchi method was applied for design of the experiment. The signal-to-noise ratio and Analysis of Variance were used to evaluate the statistical significance and contribution of each parameter to the mechanical response. The signal-to-noise ratio indicated that the optimal printing settings were as follows: printing temperature, 205 °C; infill density, 80%; infill pattern, octet; and layer height, 0.2 mm (7123.4 N). ANOVA results showed that infill density was the most significant factor affecting maximum compressive force at 60%, while infill pattern also exhibited a notable effect. According to these results, infill density and infill pattern are the most important factors for achieving high compressive strength. These findings suggest that optimizing infill architecture and density can improve the mechanical performance of PLA-wood composites, also they can offer assistive design guidelines for lightweight and eco-friendly components.

Nowadays, it is well known that on the ship, free space is at a premium. Unfortunately, every part on the ship has its duration before the failure, and the spare parts occupy the space. The broken part must be replaced when the failure occurs to maintain the ship's operation. Developing 3D printer technology and particular material technology, it has become possible to print a spare part that can replace broken. However, due to hazardous environments (salt, humidity, vibrations, etc.), printed parts change their properties. Electrical capacity and further dielectric permittivity is a parameter or metric that has to be monitored since it directly influences the printed part material structure. Therefore, this paper aims to research the impact of relative dielectric constant in additive manufacturing on printed ship's spare parts since infill patterns and density were changed due to a hazardous environment. The experiment, in which the three shaped material samples are created, consists of the following equipment, the Ultimaker S5 3D printer, Polylactic Acid (PLA) and Acrylonitrile-Butadiene-Styrene (ABS) materials, and LC HM 8018m. Results show relative dielectric constant changes between 1.7778 and 2.8141 for PLA and between 2.1979 and 2.9989 for ABS, depending on infill density and pattern. ANOVA test for ABS is performed to investigate how the calculated dielectric constant relates to the infill density for various infill shapes. Scores are: F = 154.3773, Fcrit = 5.1432, and p = 6.9269·10-6. ANOVA test for PLA resulted in scores F = 18.911, Fcrit = 5.1432, and p = 0.0022.