Simulation of edge quality in fused deposition modeling

2019 ◽  
Vol 25 (3) ◽  
pp. 541-554 ◽  
Author(s):  
Antonio Armillotta

Purpose The purpose of this paper is to propose a method for simulating the profile of part edges as a result of the FDM process. Deviations from nominal edge shape are predicted as a function of the layer thickness and three characteristic angles depending on part geometry and build orientation. Design/methodology/approach Typical patterns of edge profiles were observed on sample FDM parts and interpreted as the effects of possible toolpath generation strategies. An algorithm was developed to generate edge profiles consistent with the patterns expected for any combination of input variables. Findings Experimental tests confirmed that the simulation procedure can correctly predict basic geometric properties of edge profiles such as frequency, amplitude and shape of periodic asperities. Research limitations/implications The algorithm takes into account only a subset of the error causes recognized in previous studies. Additional causes could be integrated in the simulation to improve the estimation of geometric errors. Practical implications Edge simulation may help avoid process choices that result in aesthetic and functional defects on FDM parts. Originality/value Compared to the statistical estimation of geometric errors, graphical simulation allows a more detailed characterization of edge quality and a better diagnosis of error causes.

2017 ◽  
Vol 23 (6) ◽  
pp. 1079-1087 ◽  
Author(s):  
Antonio Armillotta ◽  
Marco Cavallaro

Purpose The purpose of this paper is to discuss the problem of the geometric accuracy of edges in parts manufactured by the Fused Deposition Modeling process, as a preliminary step for an experimental investigation. Methodology/approach Three geometric variables (inclination, included and incidence angles) were defined for an edge. The influence of each variable on the geometric errors was explained with reference to specific causes related to physical phenomena and process constraints. Findings Occurrence conditions for all causes were determined and visualized in a process map, which was also developed into a software procedure for the diagnosis of quality issues on digital models of the parts. Research limitations/implications The process map was developed by only empirical considerations and does not allow to predict the amount of geometric errors. In the second part of the paper, experimental tests will help to extend and validate the prediction criteria. Practical implications As demonstrated by an example, the results allow to predict the occurrence of visible defects on the edges of a part before manufacturing it with a given build orientation. Originality/value In literature, the geometric accuracy of additively manufactured parts is only related to surface features. The paper shows that the quality of edges depends on additional variables and causes to be carefully controlled by process choices.


2017 ◽  
Vol 23 (4) ◽  
pp. 686-695 ◽  
Author(s):  
Antonio Armillotta ◽  
Stefano Bianchi ◽  
Marco Cavallaro ◽  
Stefania Minnella

Purpose This paper aims to provide an experimental evaluation of geometric errors on the edges of parts manufactured by the fused deposition modeling (FDM) process. Design/methodology/approach An experimental plan was conducted by building parts in ABS thermoplastic resin on a commercially available machine with given combinations of the three geometric variables (inclination, included and incidence angle) defined in the first part of the paper. Edges on built parts were inspected on a two-dimensional non-contact profilometer to measure position and form errors. Findings The analysis of measurement results revealed that the edge-related variables have significant influences on the geometric errors. The interpretation of error variations with respect to the different angles confirmed the actual occurrence of the previously discussed error causes. As an additional result, quantitative predictions of the errors were provided as a function of angle values. Research limitations/implications The experimental results refer to fixed process settings (material, FDM machine, layer thickness, build parameters, scan strategies). Originality/value The two-part paper is apparently the first to have studied the edges of additively manufactured parts with respect to geometric accuracy, a widely studied topic for surface features.


2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Seung-Han Yang ◽  
Kwang-Il Lee

Purpose The purpose of this study is to improve the accuracy of a fused deposition modeling three-dimensional (3D) printer by identifying and compensating for position-independent geometric errors using a face-diagonal length test featuring a designed artifact and a Vernier caliper. Design/methodology/approach An artifact that does not require support when printing was designed and printed to allow performance of the face-diagonal length test. A Vernier caliper was used to measure the lengths of diagonals in the XY, YZ and ZX planes of the printed artifact specimen; this completed the face-diagonal length test. The relationships between position-independent geometric errors of the linear axes X, Y and Z and the measured diagonal lengths of the three planes were determined to identify geometric errors. Findings The approach was applied to a commercial fused deposition modeling 3D printer, and three position-independent geometric errors were rapidly identified. The artifact was re-printed after model-based compensation for these errors and the diagonal lengths were re-measured. The results were verified via coordinate measuring machine measurement of a simple test piece without and with model-based compensation for identified geometric errors. Furthermore, the proposed approach was applied to a commercial 3D printer. Research limitations/implications The measured diagonal lengths of the printed artifacts varied greatly. Thus, further studies should investigate the effects of printing materials and parameters on the length discrepancies of 3D printed artifacts. Practical implications A software-based compensation of identified position-independent geometric errors has to be used at commercial 3D printers for accuracy improvements of printed parts. Originality/value Thus, the approach is of practical utility; it can be periodically used to identify position-independent geometric errors and ensure that the 3D printer is consistently accurate.


2016 ◽  
Vol 22 (2) ◽  
pp. 387-404 ◽  
Author(s):  
Jonathan Torres ◽  
Matthew Cole ◽  
Allen Owji ◽  
Zachary DeMastry ◽  
Ali P. Gordon

Purpose This paper aims to present the influences of several production variables on the mechanical properties of specimens manufactured using fused deposition modeling (FDM) with polylactic acid (PLA) as a media and relate the practical and experimental implications of these as related to stiffness, strength, ductility and generalized loading. Design/methodology/approach A two-factor-level Taguchi test matrix was defined to allow streamlined mechanical testing of several different fabrication settings using a reduced array of experiments. Specimens were manufactured and tested according to ASTM E8/D638 and E399/D5045 standards for tensile and fracture testing. After initial analysis of mechanical properties derived from mechanical tests, analysis of variance was used to infer optimized production variables for general use and for application/load-specific instances. Findings Production variables are determined to yield optimized mechanical properties under tensile and fracture-type loading as related to orientation of loading and fabrication. Practical implications The relation of production variables and their interactions and the manner in which they influence mechanical properties provide insight to the feasibility of using FDM for rapid manufacturing of components for experimental, commercial or consumer-level use. Originality/value This paper is the first report of research on the characterization of the mechanical properties of PLA coupons manufactured using FDM by the Taguchi method. The investigation is relevant both in commercial and consumer-level aspects, given both the currently increasing utilization of 3D printers for component production and the viability of PLA as a renewable, biocompatible material for use in structural applications.


Molecules ◽  
2021 ◽  
Vol 26 (3) ◽  
pp. 590
Author(s):  
Tim Feuerbach ◽  
Markus Thommes

The filament is the most widespread feedstock material form used for fused deposition modeling printers. Filaments must be manufactured with tight dimensional tolerances, both to be processable in the hot-end and to obtain printed objects of high quality. The ability to successfully feed the filament into the printer is also related to the mechanical properties of the filament, which are often insufficient for pharmaceutically relevant excipients. In the scope of this work, an 8 mm single screw hot-end was designed and characterized, which allows direct printing of materials from their powder form and does not require an intermediate filament. The capability of the hot-end to increase the range of applicable excipients to fused deposition modeling was demonstrated by processing and printing several excipients that are not suitable for fused deposition modeling in their filament forms, such as ethylene vinyl acetate and poly(1-vinylpyrrolidone-co-vinyl acetate). The conveying characteristic of the screw was investigated experimentally with all materials and was in agreement with an established model from literature. The complete design information, such as the screw geometry and the hot-end dimensions, is provided in this work.


Author(s):  
Arash Alex Mazhari ◽  
Randall Ticknor ◽  
Sean Swei ◽  
Stanley Krzesniak ◽  
Mircea Teodorescu

AbstractThe sensitivity of additive manufacturing (AM) to the variability of feedstock quality, machine calibration, and accuracy drives the need for frequent characterization of fabricated objects for a robust material process. The constant testing is fiscally and logistically intensive, often requiring coupons that are manufactured and tested in independent facilities. As a step toward integrating testing and characterization into the AM process while reducing cost, we propose the automated testing and characterization of AM (ATCAM). ATCAM is configured for fused deposition modeling (FDM) and introduces the concept of dynamic coupons to generate large quantities of basic AM samples. An in situ actuator is printed on the build surface to deploy coupons through impact, which is sensed by a load cell system utilizing machine learning (ML) to correlate AM data. We test ATCAM’s ability to distinguish the quality of three PLA feedstock at differing price points by generating and comparing 3000 dynamic coupons in 10 repetitions of 100 coupon cycles per material. ATCAM correlated the quality of each feedstock and visualized fatigue of in situ actuators over each testing cycle. Three ML algorithms were then compared, with Gradient Boost regression demonstrating a 71% correlation of dynamic coupons to their parent feedstock and provided confidence for the quality of AM data ATCAM generates.


2017 ◽  
Vol 23 (4) ◽  
pp. 804-810 ◽  
Author(s):  
Shiqing Cao ◽  
Dandan Yu ◽  
Weilan Xue ◽  
Zuoxiang Zeng ◽  
Wanyu Zhu

Purpose The purpose of this paper is to prepare a new modified polybutylene terephalate (MPBT) for fused deposition modeling (FDM) to increase the variety of materials compatible with printing. And the printing materials can be used to print components with a complex structure and functional mechanical parts. Design/methodology/approach The MPBT, poly(butylene terephalate-co-isophthalate-co-sebacate) (PBTIS), was prepared for FDM by direct esterification and subsequent polycondensation using terephthalic acid (PTA), isophthalic acid (PIA), sebacic acid (SA) and 1,4-butanediol (BDO). The effects of the content of PIA (20-40 mol%) on the mechanical properties of PBTIS were investigated when the mole per cent of SA (αSA) is zero. The effects of αSA (0-7mol%) on the thermal, rheological and mechanical properties of PBTIS were investigated at nPTA/nPIA = 7/3. A desktop wire drawing and extruding machine was used to fabricate the filaments, whose printability and anisotropy were tested by three-dimensional (3D) printing experiments. Findings A candidate content of PIA introducing into PBT was obtained to be about 30 per cent, and the Izod notched impact strength of PBTIS increased with the increase of αSA. The results showed that the PBTIS (nPTA/nPIA = 7/3, αSA = 3-5mol%) is suitable for FDM. Originality/value New printing materials with good Izod notched impact strength were obtained by introducing PIA and SA (nPTA/nPIA = 7/3, αSA = 3-5 mol%) into PBT and their anisotropy are better than that of ABS.


2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Iman Sedighi ◽  
Majid R. Ayatollahi ◽  
Bahador Bahrami ◽  
Marco A. Pérez-Martínez ◽  
Andrés A. Garcia-Granada

Purpose The purpose of this paper is to study the Mode I fracture behavior of polycarbonate (PC) parts produced using fused deposition modeling (FDM). The focus of this study is on samples printed along the out-of-plane direction with different raster angles. Design/methodology/approach Tensile and Mode I fracture tests were conducted. Semi-circular bend specimens were used for the fracture tests, which were printed in four different raster patterns of (0/90), (15/−75) (30/−60) and (45/−45). Moreover, the finite element method (FEM) was used to determine the applicability of linear elastic fracture mechanics (LEFM) for the printed PC parts. The fracture toughness results, as well as the fracture path and the fracture surfaces, were studied to describe the fracture behavior of the samples. Findings Finite element results confirm that the use of LEFM is allowed for the tested PC samples. The fracture toughness results show that changing the direction of the printed rasters can have an effect of up to 50% on the fracture toughness of the printed parts, with the (+45/−45) and (0/90) orientations having the highest and lowest resistance to crack propagation, respectively. Moreover, except for the (0/90) orientation, the other samples have higher crack resistance compared to the bulk material. The fracture toughness of the tested PC depends more on the toughness of the printed sample, rather than its tensile strength. Originality/value The toughness and the energy absorption capability of the printed samples (with different raster patterns) were identified as the main properties affecting the fracture toughness of the AM PC parts. Because the fracture resistance of almost all the samples was higher than that of the base material, it is evident that by choosing the right raster patterns for 3D-printed parts, very high resistance to crack growth may be obtained. Also, using FEM and comparing the size of the plastic zones, it was concluded that, although the tensile curves show nonlinearity, LEFM is still applicable for the printed parts.


2019 ◽  
Vol 25 (5) ◽  
pp. 875-887
Author(s):  
Elnaz Asadollahi-Yazdi ◽  
Julien Gardan ◽  
Pascal Lafon

Purpose This paper aims to provide a multi-objective optimization problem in design for manufacturing (DFM) approach for fused deposition modeling (FDM). This method considers the manufacturing criteria and constraints during the design by selecting the best manufacturing parameters to guide the designer and manufacturer in fabrication with FDM. Design/methodology/approach Topological optimization and bi-objective optimization problems are suggested to complete the DFM approach for design for additive manufacturing (DFAM) to define a product. Topological optimization allows the shape improvement of the product through a material distribution for weight gain based on the desired mechanical behavior. The bi-objective optimization problem plays an important role to evaluate the manufacturability by quantification and optimization of the manufacturing criteria and constraint simultaneously. Actually, it optimizes the production time, required material regarding surface quality and mechanical properties of the product because of two significant parameters as layer thickness and part orientation. Findings A comprehensive analysis of the existing DFAM approaches illustrates that these approaches are not developed sufficiently in terms of manufacturability evaluation in quantification and optimization levels. There is no approach that investigates the AM criteria and constraints simultaneously. It is necessary to provide a decision-making tool for the designers and manufacturers to lead to better design and manufacturing regarding the different AM characteristics. Practical implications To assess the efficiency of this approach, a wheel spindle is considered as a case study which shows how this method is capable to find the best design and manufacturing solutions. Originality/value A multi-criteria decision-making approach as the main contribution is developed to analyze FDM technology and its attributes, criteria and drawbacks. It completes the DFAM approach for FDM through a bi-objective optimization problem which deals with finding the best manufacturing parameters by optimizing production time and material mass because of the product mechanical properties and surface roughness.


2019 ◽  
Vol 25 (3) ◽  
pp. 462-472 ◽  
Author(s):  
Oluwakayode Bamiduro ◽  
Gbadebo Owolabi ◽  
Mulugeta A. Haile ◽  
Jaret C. Riddick

Purpose The continual growth of additive manufacturing has increased tremendously because of its versatility, flexibility and high customization of geometric structures. However, design hurdles are presented in understanding the relationship between the fabrication process and materials microstructure as it relates to the mechanical performance. The purpose of this paper is to investigate the role of build architecture and microstructure and the effects of load direction on the static response and mechanical properties of acrylonitrile butadiene styrene (ABS) specimens obtained via the fused deposition modeling (FDM) processing technique. Design/methodology/approach Among additive manufacturing processes, FDM is a prolific technology for manufacturing ABS. The blend of ABS combines strength, rigidity and toughness, all of which are desirable for the production of structural materials in rapid manufacturing applications. However, reported literature has varied widely on the mechanical performance due to the proprietary nature of the ABS material ratio, ultimately creating a design hurdle. While prior experimental studies have studied the mechanical response via uniaxial tension testing, this study has aimed to understand the mechanical response of ABS from the materials’ microstructural point of view. First, ABS specimen was fabricated via FDM using a defined build architecture. Next, the specimens were mechanically tested until failure. Then finally, the failure structures were microstructurally investigated. In this paper, the effects of microstructural evolution on the static mechanical response of various build architecture of ABS aimed at FDM manufacturing technique was analyzed. Findings The results show that the rastering orientation of 0/90 exhibited the highest tensile strength followed by fracture at its maximum load. However, the “45” bead direction of the ABS fibers displayed a cold-drawing behavior before rupture. The morphology analyses before and after tensile failure were characterized by a scanning electron microscopy (SEM) which highlighted the effects of bead geometry (layers) and areas of stress concentration such as interstitial voids in the material during build, ultimately compromising the structural integrity of the specimens. Research limitations/implications The ability to control the constituents and microstructure of a material during fabrication is significant to improving and predicting the mechanical performance of structural additive manufacturing components. In this report, the effects of microstructure on the mechanical performance of FDM-fabricated ABS materials was discussed. Further investigations are planned in understanding the effects of ambient environmental conditions (such as moisture) on the ABS material pre- and post-fabrication. Originality/value The study provides valuable experimental data for the purpose of understanding the inter-dependency between build parameters and microstructure as it relates to the specimens exemplified strength. The results highlighted in this study are fundamental to the development of optimal design of strength and complex ultra-lightweight structure efficiency.


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