Fused Deposition Modeling Parts Research Articles

ASSESSMENT OF ASSEMBLY PROCEDURES IN FUSED DEPOSITION MODELLING PARTS

This study shows an assessment of binding techniques for parts produced by additive manufacturing (AM), specifically by fused deposition modelling (FDM). A deep search in various sources allows obtaining an updated picture of the different binding techniques for the assembly of FDM parts. The study focuses on FDM due to its wide use both at industrial and domestic levels. Although plastic parts are usually assembled using adhesives, welding or mechanical systems, the joining of AM parts needs special attention, starting at the design process of the part. The usual restrictions of AM parts makes necessary to split a big part into smaller ones, which will be later assembled together. The reduction of equipment costs and design limitations and their high flexibility have made that AM devices to experience an impressive growth recently, existing an urgent need both in the scientific and users’ community of methods for assembling AM parts. The use of smart materials is an innovative promising strategy to produce snap fits for easier disassembly processes. Keywords: additive manufacturing, 3D printing, fused deposition modeling, joining, design for assembly, smart materials

Effect of raster inclinations and part positions on mechanical properties, surface roughness and manufacturing price of printed parts produced by fused deposition method

Additive manufacturing (AM) technology has the ability to produce parts or products using data from 3D CAD models based on adding material. Fused deposition modeling (FDM) is among the most popular AM technologies wherein the plastic materials like acrylonitrile-butadiene-styrene filaments get added in the form of semi-molten plastic layers from bottom to top to produce the final product. Besides, the merits of using the FDM process, it faces challenges related to strength, dimensional accuracy, surface finish, and so on. The mechanical, tribological, and surface finish of functional parts is an essential consideration in FDM. In this work, the role of process parameters such as the part positions and raster inclinations involved in the manufacturing of parts by FDM has been evaluated experimentally to obtain the desired properties for reducing production time, the quantity of supporting material, and overall cost including maintenance costs. The study revealed that part position is a more significant parameter than the raster inclinations on the surface roughness and mechanical properties of the FDM parts. It also concludes with the proper values of part positions and raster inclinations for achieving optimal mechanical properties, roughness, and manufacturing costs to withstand operating loading conditions.

Using simple estimates for the flexural stiffness of thick FDM beams based on sandwich beam models

PurposeThe incipient growth of the fused deposition modeling (FDM) techniques encourages the development of models to predict the behavior of these parts involving complicated and heterogeneous geometries whose behavior strongly diverges from the continuous model hypothesis. This paper aims to address the problem of predicting the flexural properties of FDM parts building on the geometrical similarity between a typical FDM part and a sandwich panel.Design/methodology/approachThis paper takes advantage of the morphological similarity between FDM structures and composite sandwich panels. Thus, an approach based on classic sandwich theory is developed to validate its goodness to predict the flexural behavior of FDM parts. A set of tensile and flexural tests for FDM parts were conducted varying the density of the core pattern (10%, 15%, 20% and 25%), being the proposed model and the predicted results validated.FindingsThe results showed a good accordance between the predicted values of stiffness and the experimental data. Although this is especially evidenced for low infill density values, for densities above 20% the experimental values noticeably exceed the maximum predicted stiffness, which can be explained by the non-compliance of the foil honeycomb hypothesis for high-density patterns. The main implication of these findings lies in the possibility of using advanced models from thin-foil structures as a base to develop accurate analytical approaches to model FDM structures.Originality/valueAlthough the experimental characterization of FDM parts has been a matter of study in the literature, the development of robust theoretical models that consider the influence of the particular morphology of these parts is still a challenge in this field. The approach proposed in this study constitutes the first step to develop a complete analytical model to predict the complex behavior of FDM printed parts.

Taguchi S/N and TOPSIS Based Optimization of Fused Deposition Modelling and Vapor Finishing Process for Manufacturing of ABS Plastic Parts.

Despite several additive manufacturing techniques are commercially available in market, Fused Deposition Modeling (FDM) is increasingly used by researchers and engineers for new product development. FDM is an established process with a plethora of advantages, but the visible surface roughness (SR), being an intrinsic limitation, is major barrier against utilization of fabricated parts for practical applications. In the present study, the chemical finishing method, using vapour of acetone mixed with heated air, is being used. The combined impact of orientation angle, finishing temperature and finishing time has been studied using Taguchi and ANOVA, whereas multi-criteria optimization is performed using the Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS). The surface finish was highly responsive to increase in temperature while orientation angle of 0° yielded maximum strength; increase in finishing time led to weight gain of FDM parts. As the temperature increases, the percentage change in surface roughness increases as higher temperature assists the melt down process. On the other hand, anisotropic behaviour plays a major role during tensile testing. The Signal-to-noise (S/N) ratio plots, and ANOVA results indicated that surface finish is directly proportionate to finishing time because a longer exposure results in complete layer reflowing and settlement.

Parametric optimization of fused deposition modeling using learning enthusiasm enabled teaching learning based algorithm

This study presents an advanced Learning Enthusiasm based teaching–learning algorithm (LebTLBO) for optimization of line width compensation, extrusion speed, filling speed, and layer thickness of the Fused Deposition Modeling (FDM) process. These independent parameters have a notable effect on dimensional accuracy, warp deformation, and manufacturing time which further affects the usability of FDM parts. A comparative analysis of LebTLBO has been performed with conventional algorithms for solving a complex optimization problem. This optimization tool simulates the classroom’s teaching–learning process and demands only the common control parameters i.e. number of generations and population size instead of algorithm-specific control parameters. The findings show that LebTLBO is most efficient to chalk out single parametric settings which would maximize each response. The optimum value of parameters predicted by LebTLBO is 0.15 mm layer thickness, extrusion speed of 21.85 mm/s, and 40 mm/s filling speed for acrylonitrile butadiene styrene thermoplastic material. Confirmatory experiments validate the efficiency of LebTLBO as the maximum response is achieved at predicted parametric settings.

Modeling and optimization of fused deposition modeling (FDM) process through printing PLA implants using adaptive neuro-fuzzy inference system (ANFIS) model and whale optimization algorithm

Fused deposition modeling (FDM) is a widely used additive manufacturing (AM) technique for developing complex features and geometries within the shortest possible time as per customer needs. Nowadays, the customization of biomedical parts is becoming possible due to the increasing accuracy and enhanced ability of FDM machines to control the process parameters. The control on surface quality of parts produced by FDM process is of prime concern for the researchers, which are induced due to the stair steps on sloping surfaces, and needs addressing. In addition, to meet customer demands rapidly, the FDM part build time must be reduced without much compromising the strength of the parts necessary for specific applications. In the same context, this paper presents the effect and control of FDM process parameters, i.e., layer thickness, raster angle, infill density and internal structure, on surface roughness, build time and compressive strength of developed biomedical implant parts. The face-centered central composite design is employed to consummate the experimental trials, and experimental data are used to establish an adaptive neuro-fuzzy inference system (ANFIS) model for predicting the surface roughness, build time and compressive strength with respect to changes in FDM process parameters. At the end, whale optimization algorithm (WOA) has been applied to minimize surface roughness, minimize build time and maximize compressive strength simultaneously. Then, the optimal solutions obtained from WOA methodology have been compared with ANFIS predicted results. The results reveal that ANFIS-WOA methodology provides optimal combination of FDM process parameters accurately.

Thermally assisted finishing of fused deposition modelling build part using a novel CNC tool

Abstract The current research supports the use of commercial CNC milling machines that enables the development of new post-processing tools with a particular focus on the improvement of the surface finish of the fused deposition modelling (FDM) build part. The objective of the present research work is to develop a strategy capable to explore the option for finishing FDM build parts by conventional CNC milling machines. A major research issue in this work is to develop a finishing tool that would be compatible with commercial CNC milling machines. In this direction, a novel post-processing tool, namely thermally assisted finishing tool (TAFT) is designed and developed for thermally assisted finishing (TAF) of FDM build parts on CNC milling machines. As the surface profile of FDM parts shows different appearances in longitudinal and transversal directions, therefore, both directions were considered during TAF operation. Through surface roughness improvement and adaptability of the proposed technique, the effectiveness of the TAF tool was analyzed and studied. The analysis results showed that the selective melting played an important role in improving the surface finish conditions. The comparative data study shows the use of the TAF tool is more user adaptable, due to its easy compatibility with commercial CNC milling machines and provides future direction in the area of post-processing of FDM build parts.

Effects of laser scanning speed on surface roughness and mechanical properties of aluminum/Polylactic Acid (Al/PLA) composites parts fabricated by fused deposition modeling

Although fused deposition modeling (FDM) has gradually become one of the popular additive manufacturing technologies in different industries, high surface roughness has always been an inevitable disadvantage of FDM parts. Laser polishing represents a recent and novel application of laser surface irradiation that can be used for precise, post-process smoothing of the rough surfaces commonly encountered on FDM parts. The influence of laser polishing on surface modification and mechanical properties of aluminum/Polylactic Acid (Al/PLA) composites has been investigated. Laser scanning speed was varied to evaluate its effect on the surface quality and mechanical properties of the experimental samples. The results indicated that laser polishing could enable reductions in surface roughness of over 86.6% (from 23.27 μm to 3.11 μm Sa). The tensile strength of specimen also increased from 41.01 MPa to 51.31 MPa with increasement of 25.1%. The dynamic mechanical analysis (DMA) results showed that there was a remarkable improvement in the storage modulus and glass transition temperature of Al/PLA composite specimens after laser polishing, which suggested that the laser polishing treatment could play a role in decreasing the porosity inside the FDM parts and improve interfacial adhesion between the PLA matrix and Al fibers. Moreover, the fracture morphologies were observed to investigate the possible strengthening mechanism. These results demonstrate how laser polishing can simultaneously smooth and modify the surface characteristics of a FDM part surface.

Quantitative analysis of surface treatment to enhance surface finish and mechanical characteristics of ABS parts

Lack of surface integrity and porosity are the key factors limiting the growth of fused deposition modelling (FDM) method. The method requires an efficient post processing technique which is consistent, controllable and predictable to improve surface finish without affecting geometrical and mechanical properties. This work aims to setup a novel method to treat FDM parts to improve surface quality as well as heat absorption, which in turn makes it suitable for high temperature applications. In this process, Acrylonitrile Butadiene Styrene (ABS) parts are treated with montmorillonite nanoclay via acetone bathing. The parameters like layer thickness, nanoclay content and immersion time were considered for the investigation. The roughness is measured based on the deviation from the least square plane fixed to the computed surface topography data sets, which allows to investigate the influence of smoothing parameters. Further, parts have been investigated for thermal and mechanical properties to predict optimal smoothing parameters. Results showed the proposed surface treatment method could effectively reduce the roughness of the ABS parts. In addition, nanoclay coating showed remarkable effect on the ultimate tensile strength (UTS), reflection of heat radiation resulting in the reduction of heat absorption.

Topology Optimization for FDM Parts Considering the Hybrid Deposition Path Pattern.

Based on a solid orthotropic material with penalization (SOMP) and a double smoothing and projection (DSP) approach, this work proposes a methodology to find an optimal structure design which takes the hybrid deposition path (HDP) pattern and the anisotropic material properties into consideration. The optimized structure consists of a boundary layer and a substrate. The substrate domain is assumed to be filled with unidirectional zig-zag deposition paths and customized infill patterns, while the boundary is made by the contour offset deposition paths. This HDP is the most commonly employed path pattern for the fused deposition modeling (FDM) process. A critical derivative of the sensitivity analysis is presented in this paper, which ensures the optimality of the final design solutions. The effectiveness of the proposed method is validated through several 2D numerical examples.

Statistical process monitoring in a specified period for the image data of fused deposition modeling parts with consistent layers

Statistical process monitoring (SPM) methods have been adopted and studied to detect variations in the fused deposition modeling (FDM) process in recent years. The FDM process that builds parts layer-by-layer is accomplished in a specified manufacturing period (number of layers) without interruption or suspension. Thus, traditional SPM methods, where the average run length is used for the calculation of the control limits and the measurement of the performance, are no longer applicable to the FDM process. In this paper, an SPM method is proposed based on the surface image data of FDM parts with consistent layers and a specified period. The probability of alarm in a specified period (PASP) and the cumulative PASP are introduced to determine the control limits and evaluate the monitoring performance. Regions of interest are determined in a fixed way to cover the sizes and locations of different defects. The statistics are calculated based on the generalized likelihood ratio. The control limit is determined based on the specified period and the nominal in-control PASP. A simulation study for different locations, sizes and magnitudes of the mean shift of defects is presented. In the case study, the proposed SPM method is applied to monitor the FDM process of a cuboid, which verifies the effectiveness of the proposed method.

Effects of auxiliary heat on warpage and mechanical properties in carbon fiber/ABS composite manufactured by fused deposition modeling

Fused Deposition Modeling (FDM) technology offers opportunities for high-efficiency design and low-cost manufacturing of 3D complex parts in additive manufacturing (AM). The warpage remains a big problem which prevents the industrial application of FDM parts, especially parts fabricated by fiber-reinforced composite. In this study, an auxiliary heating plate was developed and mounted on the printing head of an FDM 3D printer to suppress the warpage of the parts made with short carbon fiber (CF)-reinforced acrylonitrile-butadiene-styrene copolymers (ABS) composites. It is found that auxiliary heating and raster angle of FDM process are the two dominating parameters on the tensile properties and the warpage of FDM parts. For the best parameter combination, 160 oC for auxiliary heating temperature and 0 degree for raster angle, the warpage was completely suppressed and the tensile strength got 31% enhancement, ductility got 439% enhancement compared to the FDM part without auxiliary heating and 0 degree in raster angle. Cyclic fatigue behavior and anisotropy of CF/ABS specimen was also significantly improved by auxiliary heating treatment. The reduced stain caused by the annealing ability of auxiliary heating during the 3D printing, is responsible for this enhancement. Compared with auxiliary heating and post thermal annealing treatment, the tensile property and cyclic fatigue behavior of CF/ABS specimen was equivalent. Notably, auxiliary heating is the “in-situ” annealing during the process of 3D printing, which can break through the existing dimension constraints of post thermal annealing treatment. Therefore, the approach broadens the design for CF/ABS composites through temperature-specific optimization and makes it possible to fabricate huge-size FDM parts.

An experimental methodology to analyse the structural behaviour of FDM parts with variable process parameters

Purpose This paper aims to investigate the structural behaviour of polylactic acid (PLA) parts fabricated by fused deposition modelling (FDM) to support the development of analytical and numerical models to predict the structural performance of FDM components and categories of similar additive manufactured parts. Design/methodology/approach A new methodology based on uniaxial tensile tests of filaments and FDM specimens, infill measurement and normalization of the results is proposed and implemented. A total of 396 specimens made of PLA were evaluated by using variable process parameters. Findings The infill and the build orientation have a large influence on the elastic modulus and ultimate tensile stress, whereas the layer thickness and the infill pattern have a low influence on these properties. The elongation at break is not influenced by the process parameters except by the build orientation. Furthermore, the infill values measured on the test specimens differ from the nominal values provided by the system. Research limitations/implications The analysis of the structural properties of FDM samples is limited to uniaxial loading conditions. Practical implications The obtained results are valuable for the structural analysis and numerical simulation of FDM components and for potential studies using machine learning techniques to predict the structural response of FDM parts. Originality/value A new experimental methodology that considers the measurement of the real infill percentage and the normalization of the results for inter-comparison with other studies is proposed. Moreover, a new set of experimental results of FDM-PLA parts is presented and extends the existing results in the literature.

Experimental study of surface roughness, dimensional accuracy and time of fabrication of parts produced by fused deposition modelling

Purpose This paper aims to focus on an experimental study of surface roughness, dimensional accuracy and time of fabrication of parts produced by fused deposition modelling (FDM) technique of additive manufacturing. The fabricated parts of acrylonitrile butadiene styrene (ABS) material have pyramidal and conical features. Influence of five process parameters of FDM, namely, layer thickness, wall print speed, build orientation, wall thickness and extrusion temperature is studied on response characteristics. Furthermore, regression models for responses are developed and significant process parameters are optimized. Design/methodology/approach Comprehensive experimental study is performed using response surface methodology. Analysis of variance is used to investigate the influence of process parameters on surface roughness, dimensional accuracy and time of fabrication in both outer pyramidal and inner conical regions of part. Furthermore, a multi-response optimization using desirability function is performed to minimize surface roughness, improve dimensional accuracy and minimize time of fabrication of parts. Findings It is found that layer thickness and build orientation are significant process parameters for surface roughness of parts. Surface roughness increases with increase in layer thickness, while it decreases initially and then increases with increase in build orientation. Layer thickness, wall print speed and build orientation are significant process parameters for dimensional accuracy of FDM parts. For the time of fabrication, layer thickness and build orientation are found as significant process parameters. Based on the analysis, statistical non-linear quadratic models are developed to predict surface roughness, dimensional accuracy and time of fabrication. Optimization of process parameters is also performed using desirability function. Research limitations/implications The present study is restricted to the parts of ABS material with pyramidal and conical features only fabricated on FDM machine with delta configuration. Originality/value From the critical review of literature it is found that some researchers have made to study the influence of few process parameters on surface roughness, dimensional accuracy and time of fabrication of simple geometrical parts. Also, regression models and optimization of process parameters has been performed for simple parts. The present work is focussed on studying all these aspects in complicated geometrical parts with pyramidal and conical features.

An Experimental Study of Surface Improvement in FDM Parts by Vapor Treatment Process

Fused deposition modeling (FDM) is one of the most adaptable additive manufacturing method owing to the cost-effectiveness and environment-friendly nature. However, FDM technique still possesses major difficulties in terms of poor surface quality because of adding layer by layer manufacturing process for the prototypes. It is desirable to explore an efficient technique for FDM parts to enhance the poor surface quality and dimensions precision. In the present paper, an effort has been made to enhance the surface quality and optimize the critical processing parameter of FDM based benchmark using vapor smoothing process (VSP). A comparative experimental study has been performed by design of experiments (DOE), Taguchi technique to find the influence of input design parameters on the surface finish of benchmark FDM parts. The results of the present investigation show that VSP treatment improves the surface quality of FDM parts to micro level with negligible dimensional variation. It is observed that improved surface quality is found in the 1,2, -Dichloroethane chemical at 90° part build orientation, 0.25 mm layer thickness, 10% fill density and 90 second exposure times.

Time-Dependent Mechanical Properties in Polyetherimide 3D-Printed Parts Are Dictated by Isotropic Performance Being Accurately Predicted by the Generalized Time Hardening Model.

The Fused-Deposition Modelling (FDM) technique has transformed the manufacturing discipline by simplifying operational processes and costs associated with conventional technologies, with polymeric materials being indispensable for the development of this technology. A lack of quantification of viscoelastic/plastic behavior has been noted when addressing FDM parts with Polyetherimide (PEI), which is currently being investigated as a potential material to produce functional end-products for the aerospace and health industry. Primary and secondary creep along with stress relaxation tests have been conducted on FDM PEI specimens by applying stresses from 10 to 40 MPa for 100 to 1000 min. Specimens were 3D printed by varying the part build orientation, namely XY, YZ, and XZ. Creep results were fitted to the Generalized Time Hardening equation (GTH), and then this model was used to predict stress relaxation behavior. FDM PEI parts presented an isotropic creep and stress relaxation performance. The GTH model was proven to have a significant capacity to fit viscoelastic/plastic performances for each single build orientation (r > 0.907, p < 0.001), as well as a tight prediction of the stress relaxation behavior (r > 0.998, p < 0.001). Averaged-orientation coefficients for GTH were also closely correlated with experimental creep data (r > 0.958, p < 0.001) and relaxation results data (r > 0.999, p < 0.001). FDM PEI parts showed an isotropic time-dependent behavior, which contrasts with previous publications arguing the significant effect of part build orientation on the mechanical properties of FDM parts. These findings are strengthened by the high correlation obtained between the experimental data and the averaged-coefficient GTH model, which has been proven to be a reliable tool to predict time-dependent performance in FDM parts.

Influence of different post-processing methods on surface topography of fused deposition modelling samples

Additive Manufacturing (AM) is gaining prominence due to its massive advantage in fabricating components without any geometrical limitations. The most widely used AM technique is Fused Deposition Modelling (FDM). FDM is an extrusion-based AM mostly focused on producing functional prototypes and in some cases as an end-product. One of the most common challenges associated with FDM is its reduced dimensional accuracy and surface quality. A fair amount of research has been carried out to identify the factors affecting print quality and measures to reduce surface roughness. On a few occasions, it is still necessary to achieve higher precision and quality to meet the standards set by conventional manufacturing. Hence, post-processing is employed as an additional step to reach the finish required. This paper focuses on enhancing the surface quality of FDM parts by subjecting it to Acetone vapour smoothening, Shot-blasting and Laser-assisted finishing post-processing methods. A comparative study is presented in this paper, where surface produced by different post-processing methods were compared to the reference injection moulding components. The results suggest that the acetone-based process has the best surface finish compared to the other two means; however, it leaves a very glossy appearance to the part. Shot blasting is very aggressive, and blasting time has a strong influence on the part quality. Laser-assisted finishing slightly ignites the top layer during melting leading to discolouration of the part. The optimum solution was found to be combining the post-processes, which not only reduced the roughness but also enhanced the aesthetic properties of the product.

Mechanical study on the impact of an effective solvent support-removal methodology for FDM Ultem 9085 parts

The use of support material to produce Fused Deposition Modeling parts is often unavoidable. The support removal task tends to be laborious and time-consuming when no soluble support materials are available, which is the case of the high-performance thermoplastic Ultem™ 9085. This paper investigates the effect of different solvent/solvent mixtures on Ultem’s mechanical properties with the aim to identify a solvent capable of dissolving its support material (a polysulfone) without noticeably damaging the model material. To do so, initial solubility tests have helped narrow the list of solvent candidates. These have been followed by infrared analyses to identify the presence of dissolved polymers in the media, as well as scanning electron microscope micrographs to analyze the surface topography of the treated parts. Finally, tensile and flexural tests have permitted to quantify the change on Ultem’s mechanical properties as a function of the treatment time. Major findings include a reproducible method for softening or eliminating Ultem’s support material with non-significant changes in their mechanical properties. The outcome of this work represents a first step on the lookout for a solution to facilitate the removal of polysulfone and is considered of great interest for the scientific community due to the rise of Ultem as a structural material.

Mechanical Characterization of PC-ABS Reinforced with CNT Nanocomposites developed by Fused Deposition Modelling

Fused Deposition Modeling (FDM), a category of Additive Manufacturing (AM) is a versatile form of manufacturing technology that enables the development of the part layer by layer, of any complex geometry. The development and utilization of polymer nanocomposites for has seen a wide range of implementation. The development of polymer nanocomposite by fused deposition technology and evaluation of its mechanical propertieshave been carried out in this study. Polycarbonate (PC) and Acrylonotrile Butadiene Styrene (ABS) are compounded together with carbon nanotubes. Different proportion of Carbon Nano Tubes (CNT) was added as reinforcement at to PC-ABS matrix. Two variations of samples were developed with incremental addition of CNT to PC-ABS. Ultimate tensile strength and impact strength were analyzed for the developed nano composite FDM parts. It was observed that, with the addition of CNT the ultimate tensile strength of the parts increased significantly. Similar trend was seen for impact strength as well.

Mechanical characterization and comparison of additive manufactured ABS, Polyflex™ and ABS/Polyflex™ blended functional prototypes

Purpose Additive manufacturing (AM) is one of the latest and most advanced technologies that are continuously expanding into various field applications. Undoubtedly, fused deposition modeling (FDM) is one of the oldest and extensively used AM technologies not only because of the advantage of low cost, comparatively moderate production speed and negligible wastage but also due to acceptance of a wide range of thermoplastics, reinforced and blended feedstock for making the end product suitable for service. The purpose of this work to perform mechanical characterization of standard samples printed on FDM with acrylonitrile butadiene styrene (ABS), shape memory polymer (SMP; make PolyflexTM) and ABS/PolyflexTM blend and a comparative study from AM view point. Design/methodology/approach A low-cost desktop-based FDM setup was used for the fabrication of the test specimens under different processing conditions. Experiments were conducted as per obtained control log, and statistical analysis was conducted to understand the effect of selected variables in response of measured properties. Further, scanning electron microscopy-based micrographs were analyzed to understand the fracture mechanisms. Findings The obtained results highlighted that the mechanical properties of FDM parts are strongly influenced by the selected process variables. However, in case of most of the measured properties, selection of suitable feedstock has dominated the other input variables. Further, the results of test parts made with in-house developed ABS/SMP blend have showed the attainment of remarkable values of both strength and elasticity. Originality/value This work is held to empower the use of FDM technology to fabricate advanced and robust components for serving highly demanding applications.