scholarly journals Stress-limiting test structures for rapid low-cost strength and stiffness assessment

2015 ◽  
Vol 21 (2) ◽  
pp. 144-151 ◽  
Author(s):  
Andrew Katz ◽  
Justin Nussbaum ◽  
Craig P Lusk ◽  
Nathan B Crane
Keyword(s):  
Fused Deposition Modeling ◽  
Low Cost ◽  
Test Methods ◽  
Measurement Sensitivity ◽  
Content Type ◽  
Fused Deposition ◽  
Deposition Modeling ◽  
Strength And Stiffness ◽  
Accuracy And Repeatability ◽  
Printing Parameters

Purpose – The purpose of this paper is to evaluate the use of a simple printed geometry to estimate mechanical properties (elastic modulus, yield strength) with inexpensive test equipment. Design/methodology/approach – Test geometry is presented that enables controlled strains with manual deformation and repeatable measurement of vibrational frequencies. This is tested with multiple fused deposition modeling (FDM) machines to assess measurement accuracy and repeatability. Printing orientation and some printing parameters are varied to assess the measurement sensitivity. Findings – The test methods show good correlation with manufacturer material specifications in the X-Y plane and reported elastic strain limits. It is also sensitive to printing orientation and printing parameters. Research limitations/implications – Further work is needed to assess the sensitivity of the method to particular defects and parameter errors expected in particular applications. Originality/value – This method supports process monitoring in production environments and inexpensive assessments of material properties for hobbyist and do-i- yourself users. While it is tested with FDM, it should be applicable to other additive manufacturing processes.

Fused deposition modeling with polyamide 1012

2019 ◽  
Vol 25 (7) ◽  
pp. 1145-1154 ◽  
Author(s):  
Xia Gao ◽  
Daijun Zhang ◽  
Xiangning Wen ◽  
Shunxin Qi ◽  
Yunlan Su ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Fused Deposition Modeling ◽  
Mechanical Performance ◽  
Content Type ◽  
Good Ductility ◽  
Fused Deposition ◽  
Bed Temperature ◽  
Deposition Modeling ◽  
Nozzle Temperature ◽  
Printing Parameters

Purpose This work aims to develop a new kind of semicrystalline polymer filament and optimize its printing parameters in the fused deposition modeling process. The purpose of this work also includes producing FDM parts with good ductility. Design/methodology/approach A new kind of semicrystalline filaments composed of long-chain polyamide (PA)1012 was prepared by controlling screw speed and pulling speed carefully. The optimal printing parameters for PA1012 filaments were explored through investigating dimensional accuracy and bonding strength of FDM parts. Furthermore, the mechanical properties of PA1012 specimens were also evaluated by varying nozzle temperatures and raster angles. Findings It is found that PA1012 filaments can accommodate for FDM process under suitable printing parameters. The print quality and mechanical properties of FDM parts highly depend on nozzle temperature and bed temperature. Even though higher temperatures facilitate stronger interlayer bonding, FDM parts with excellent tensile strength were obtained at a moderate nozzle temperature. Moreover, a bed temperature well above the glass transition temperature of PA1012 can eliminate shrinkage and distortion of FDM parts. As expected, FDM parts prepared with PA1012 filaments exhibit good ductility. Originality/value Results in this work demonstrate that the PA1012 filament allows the production of FDM parts with desired mechanical performance. This indicates the potential for overcoming the dependence on amorphous thermoplastics as a feedstock in the FDM technique. This work also provides insight into the effect of materials properties on the mechanical performance of FDM-printed parts.

An Update on the Use of Alginate in Additive Biofabrication Techniques

2019 ◽  
Vol 25 (11) ◽  
pp. 1249-1264 ◽  
Author(s):  
Amoljit Singh Gill ◽  
Parneet Kaur Deol ◽  
Indu Pal Kaur
Keyword(s):  
Fused Deposition Modeling ◽  
Low Cost ◽  
Selective Laser Sintering ◽  
Layer By Layer ◽  
Three Dimension ◽  
Anionic Polymer ◽  
Fused Deposition ◽  
The Status ◽  
Deposition Modeling ◽  
Extrusion Printing

Background: Solid free forming (SFF) technique also called additive manufacturing process is immensely popular for biofabrication owing to its high accuracy, precision and reproducibility. Method: SFF techniques like stereolithography, selective laser sintering, fused deposition modeling, extrusion printing, and inkjet printing create three dimension (3D) structures by layer by layer processing of the material. To achieve desirable results, selection of the appropriate technique is an important aspect and it is based on the nature of biomaterial or bioink to be processed. Result & Conclusion: Alginate is a commonly employed bioink in biofabrication process, attributable to its nontoxic, biodegradable and biocompatible nature; low cost; and tendency to form hydrogel under mild conditions. Furthermore, control on its rheological properties like viscosity and shear thinning, makes this natural anionic polymer an appropriate candidate for many of the SFF techniques. It is endeavoured in the present review to highlight the status of alginate as bioink in various SFF techniques.

Synthesis and properties of modified PBT for FDM

2017 ◽  
Vol 23 (4) ◽  
pp. 804-810 ◽  
Author(s):  
Shiqing Cao ◽  
Dandan Yu ◽  
Weilan Xue ◽  
Zuoxiang Zeng ◽  
Wanyu Zhu
Keyword(s):  
Mechanical Properties ◽  
Impact Strength ◽  
Fused Deposition Modeling ◽  
Complex Structure ◽  
Three Dimensional ◽  
Sebacic Acid ◽  
Wire Drawing ◽  
Content Type ◽  
Fused Deposition ◽  
Deposition Modeling

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.

Fracture assessment of polycarbonate parts produced by fused deposition modeling in the out-of-plane printing direction – effect of raster angle

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
Keyword(s):  
Fracture Toughness ◽  
Finite Element ◽  
Fracture Behavior ◽  
Fused Deposition Modeling ◽  
Mode I ◽  
Content Type ◽  
Fused Deposition ◽  
Out Of Plane ◽  
Deposition Modeling ◽  
Fracture Tests

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.

scholarly journals 3D Printing of Functional Assemblies with Integrated Polymer-Bonded Magnets Demonstrated with a Prototype of a Rotary Blood Pump

2018 ◽  
Vol 8 (8) ◽  
pp. 1275 ◽  
Author(s):  
Kai von Petersdorff-Campen ◽  
Yannick Hauswirth ◽  
Julia Carpenter ◽  
Andreas Hagmann ◽  
Stefan Boës ◽  
...  
Keyword(s):  
Fused Deposition Modeling ◽  
Permanent Magnets ◽  
Low Cost ◽  
Magnetic Bearing ◽  
Blood Pump ◽  
Rotary Blood Pump ◽  
Pump Impeller ◽  
Fused Deposition ◽  
Magnetic Components ◽  
Deposition Modeling

Conventional magnet manufacturing is a significant bottleneck in the development processes of products that use magnets, because every design adaption requires production steps with long lead times. Additive manufacturing of magnetic components delivers the opportunity to shift to agile and test-driven development in early prototyping stages, as well as new possibilities for complex designs. In an effort to simplify integration of magnetic components, the current work presents a method to directly print polymer-bonded hard magnets of arbitrary shape into thermoplastic parts by fused deposition modeling. This method was applied to an early prototype design of a rotary blood pump with magnetic bearing and magnetic drive coupling. Thermoplastics were compounded with 56 vol.% isotropic NdFeB powder to manufacture printable filament. With a powder loading of 56 vol.%, remanences of 350 mT and adequate mechanical flexibility for robust processability were achieved. This compound allowed us to print a prototype of a turbodynamic pump with integrated magnets in the impeller and housing in one piece on a low-cost, end-user 3D printer. Then, the magnetic components in the printed pump were fully magnetized in a pulsed Bitter coil. The pump impeller is driven by magnetic coupling to non-printed permanent magnets rotated by a brushless DC motor, resulting in a flow rate of 3 L/min at 1000 rpm. For the first time, an application of combined multi-material and magnet printing by fused deposition modeling was shown. The presented process significantly simplifies the prototyping of products that use magnets, such as rotary blood pumps, and opens the door for more complex and innovative designs. It will also help postpone the shift to conventional manufacturing methods to later phases of the development process.

Multi-objective optimization approach in design for additive manufacturing for fused deposition modeling

2019 ◽  
Vol 25 (5) ◽  
pp. 875-887
Author(s):  
Elnaz Asadollahi-Yazdi ◽  
Julien Gardan ◽  
Pascal Lafon
Keyword(s):  
Optimization Problem ◽  
Fused Deposition Modeling ◽  
Topological Optimization ◽  
Design For Additive Manufacturing ◽  
Multi Objective Optimization ◽  
Content Type ◽  
Fused Deposition ◽  
Design And Manufacturing ◽  
Deposition Modeling ◽  
Manufacturing Parameters

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.

The influence of load direction, microstructure, raster orientation on the quasi-static response of fused deposition modeling ABS

2019 ◽  
Vol 25 (3) ◽  
pp. 462-472 ◽  
Author(s):  
Oluwakayode Bamiduro ◽  
Gbadebo Owolabi ◽  
Mulugeta A. Haile ◽  
Jaret C. Riddick
Keyword(s):  
Additive Manufacturing ◽  
Fused Deposition Modeling ◽  
Mechanical Response ◽  
Mechanical Performance ◽  
Bead Geometry ◽  
Static Response ◽  
Load Direction ◽  
Content Type ◽  
Fused Deposition ◽  
Deposition Modeling

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.

Simulation of edge quality in fused deposition modeling

2019 ◽  
Vol 25 (3) ◽  
pp. 541-554 ◽  
Author(s):  
Antonio Armillotta
Keyword(s):  
Fused Deposition Modeling ◽  
Experimental Tests ◽  
Geometric Errors ◽  
Content Type ◽  
Fused Deposition ◽  
Graphical Simulation ◽  
Deposition Modeling ◽  
Edge Quality ◽  
Input Variables

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.

scholarly journals Comparison Of FEA Simulations And Experimental Results For As-Built Additively Manufactured Dogbone Specimens

2021 ◽  
Author(s):  
Prathamesh Baikerikar ◽  
Cameron J Turner
Keyword(s):  
Fused Deposition Modeling ◽  
Experimental Tests ◽  
Continuum Models ◽  
Element Analysis ◽  
Fused Deposition ◽  
Accuracy And Precision ◽  
Structure Strength ◽  
Deposition Modeling ◽  
End Use ◽  
Strength And Stiffness

Abstract Parts built using Fused Deposition Modeling (FDM – an additive manufacturing technology) differ from their design model in terms of their microstructure and material properties. These differences lead to a certain amount of ambiguity regarding the structure, strength and stiffness of the final FDM part. Increasing use of FDM parts as end use products, necessitates accurate simulations and analyses during part design. However, analysis methods such as Finite Element Analysis, are used for analysis of continuum models, and may not accurately represent the non-continuous non-linear FDM parts. Therefore, it is necessary to determine the accuracy and precision of FEA for FDM parts. The goal of this study is to compare FEA simulations of the as-built geometries with the experimental tests of actual FDM parts. Dogbone geometries that include different infill patterns are tested under tensile loading and later simulated using FEA. This study found that FEA results are not always an accurate or reliable means of predicting FDM part behaviors.

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