Nano-CT Characterization of Structural Voids and Air Bubbles in Fused Deposition Modeling for Additive Manufacturing

2015 ◽  
Author(s):  
Roland K. Chen ◽  
Terris T. Lo ◽  
Lei Chen ◽  
Albert J. Shih
Keyword(s):  
Fused Deposition Modeling ◽  
Three Dimensional ◽  
Material Testing ◽  
Air Bubbles ◽  
Part Quality ◽  
Fused Deposition ◽  
Deposition Modeling ◽  
Non Destructive

The build quality of fused deposition modeling (FDM) parts depends on many build parameters, such as toolpath and temperature. Destructive material testing methods are widely used to examine FDM parts with different build parameters. The optimization of build parameters relies on methods of experimental design and extensive material testing. However, this approach mainly considers the bulk properties of the FDM part, without fully understanding the effect of each parameter on the build quality. This study presents a method to investigate the integrity of FDM parts using nano-focus computed tomography (NanoCT). A solid filled ULTEM sample was built and underwent NanoCT scan. The three dimensional geometry of this sample was reconstructed. Structural voids and bubbles inside the sample were also identified and quantified. The volume of this solid filled sample consists of 11.9% structural voids and bubbles. Air bubbles are further categorized into internal bubbles (bubbles inside the deposited fibers) and necking bubbles (bubbles at the bonding region of two adjacent fibers). While structural voids can be predicted according to toolpath, layer thickness, and extruder diameter, the occurrence of air bubbles are unexpected and can compromise the integrity of the built parts. NanoCT offers a non-destructive way to inspect the integrity of FDM parts. NanoCT can also be used to study three dimensional meso-structure and correlate that with build parameters. This will provide insightful information for further studying the FDM process and help to predict material strengths and to improve the part quality.

scholarly journals Automated Testing and Characterization of Additive Manufacturing (ATCAM)

2021 ◽  
Author(s):  
Arash Alex Mazhari ◽  
Randall Ticknor ◽  
Sean Swei ◽  
Stanley Krzesniak ◽  
Mircea Teodorescu
Keyword(s):  
Additive Manufacturing ◽  
Fused Deposition Modeling ◽  
Cell System ◽  
Automated Testing ◽  
Fused Deposition ◽  
Deposition Modeling ◽  
Machine Calibration

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.

Surface Characterization in Fused Deposition Modeling

3D Printing ◽  
2017 ◽  
pp. 22-47 ◽  
Author(s):  
Alberto Boschetto ◽  
Luana Bottini
Keyword(s):  
Surface Characterization ◽  
Fused Deposition Modeling ◽  
Prediction Models ◽  
Great Effort ◽  
Roughness Parameters ◽  
Fused Deposition ◽  
Design Specifications ◽  
Deposition Modeling

Fused deposition modeling is a proven technology, widely diffused in industry, born for the fabrication of aesthetic and functional prototypes. Recently used for small and medium series of parts and for tooling, it received particular attention in order to integrate prototyping systems within production. A limiting aspect of this technology is the obtainable roughness and above all its prediction: no machine software and Computer-Aided Manufacturing implements a relationship between process parameters and surface quality of components. The prediction of the surface properties is an essential tool that allows it to comply with design specifications and, in process planning, to determine manufacturing strategies. Recently, great effort has been spent to develop a characterization of such surfaces. In this chapter, prediction models are presented and a new characterization approach is detailed. It is based on the theoretical prediction of the geometrical roughness profile, thus allowing it to obtain, in advance, all roughness parameters.

Surface Characterization in Fused Deposition Modeling

2014 ◽  
pp. 249-280 ◽  
Author(s):  
Alberto Boschetto ◽  
Luana Bottini
Keyword(s):  
Surface Characterization ◽  
Fused Deposition Modeling ◽  
Prediction Models ◽  
Great Effort ◽  
Roughness Parameters ◽  
Fused Deposition ◽  
Design Specifications ◽  
Deposition Modeling

Fused deposition modeling is a proven technology, widely diffused in industry, born for the fabrication of aesthetic and functional prototypes. Recently used for small and medium series of parts and for tooling, it received particular attention in order to integrate prototyping systems within production. A limiting aspect of this technology is the obtainable roughness and above all its prediction: no machine software and Computer-Aided Manufacturing implements a relationship between process parameters and surface quality of components. The prediction of the surface properties is an essential tool that allows it to comply with design specifications and, in process planning, to determine manufacturing strategies. Recently, great effort has been spent to develop a characterization of such surfaces. In this chapter, prediction models are presented and a new characterization approach is detailed. It is based on the theoretical prediction of the geometrical roughness profile, thus allowing it to obtain, in advance, all roughness parameters.

scholarly journals Process of Manufacturing Transparent Models of Anatomical Structures

2020 ◽  
Vol 44 (2) ◽  
pp. 62-66
Author(s):  
Wiktoria Wojnarowska ◽  
Maciej Nieroda ◽  
Ewelina Gładysz ◽  
Sławomir Miechowicz ◽  
Tomasz Kudasik
Keyword(s):  
3D Printing ◽  
Fused Deposition Modeling ◽  
Three Dimensional ◽  
New Method ◽  
Fused Deposition ◽  
Internal Structures ◽  
Huge Impact ◽  
Deposition Modeling ◽  
Surgical Treatments

AbstractIn recent years, a rapid increase in the use of three-dimensional (3D) printing technologies in medicine, especially in the manufacturing of the diagnostic models, can be observed. In some cases, there is a need to fabricate transparent models that allow visualization of internal structures of the object. Unfortunately, techniques used to manufacture such models are often very expensive and time-consuming. The above-mentioned issues were the motivation for developing a new method of fabrication transparent models for visualization of internal structures for planning surgical treatments. This paper presents the process of making transparent models using the newly developed method – the stacked layers method. In order to compare this new method and one of the most common 3D printing technologies – fused deposition modeling (FDM) – the models for two medical cases using both of these methods were fabricated. As a result of this work, it can be concluded that the stacked layers method provides faster and cheaper way of making transparent medical models. The main features of fabrication process that have a huge impact on quality of the models made by new method were pointed. The results of this study suggest that models fabricated with the use of this method can be useful as a diagnostic tool in medical applications for planning surgical treatments.

Analysis of Extrusion Parameters for the Fused Deposition Modeling Process

2020 ◽  
Author(s):  
Wenqiang Yu ◽  
Zhengwei Nie ◽  
Yuyi Lin ◽  
Huakai Jiang
Keyword(s):  
Fused Deposition Modeling ◽  
Three Dimensional ◽  
Three Dimensional Printing ◽  
Technical Parameters ◽  
Fused Deposition ◽  
Modeling Process ◽  
Deposition Modeling ◽  
Dimensional Printing ◽  
Screw Pitch

Abstract Fused deposition modeling (FDM) is an additive manufacturing technology commonly used for three-dimensional printing. The screw rod is an important part of the extrusion nozzle in the FDM manufacturing. The technical parameters of the screw rod, such as the screw pitch, screw angle, groove width, and length-diameter ratio (or aspect ratio), etc., directly determine the speed of extrusion and the precision of modeling. To improve the printing speed and quality of FDM models, this work analyzed the influence of extrusion screw’s parameters on the extrusion flow rate and proposed the best parameters for the screw rod of the FDM process. The results of this work have a crucial significance on the modeling speed and accuracy of the FDM.

Thermal characterization of ABS-Graphene blended three dimensional printed functional prototypes for electro chemical energy storage

2018 ◽  
Vol 1 (1) ◽  
pp. 1-11 ◽  
Author(s):  
Kamaljit Singh Boparai ◽  
Rupinder Singh
Keyword(s):  
Energy Storage ◽  
Structural Changes ◽  
Fused Deposition Modeling ◽  
Morphological Changes ◽  
Three Dimensional ◽  
Thermal Characterization ◽  
Chemical Energy ◽  
Flow Index ◽  
Fused Deposition

This study highlights the thermal characterization of ABS-Graphene blended three dimensional (3D) printed functional prototypes by fused deposition modeling (FDM) process. These functional prototypes have some applications as electro-chemical energy storage devices (EESD). Initially, the suitability of ABS-Graphene composite material for FDM applications has been examined by melt flow index (MFI) test. After establishing MFI, the feedstock filament for FDM has been prepared by an extrusion process. The fabricated filament has been used for printing 3D functional prototypes for printing of in-house EESD. The differential scanning calorimeter (DSC) analysis was conducted to understand the effect on glass transition temperature with the inclusion of Graphene (Gr) particles. It has been observed that the reinforced Gr particles act as a thermal reservoir (sink) and enhances its thermal/electrical conductivity. Also, FT-IR spectra realized the structural changes with the inclusion of Gr in ABS matrix. The results are supported by scanning electron microscopy (SEM) based micrographs for understanding the morphological changes.

Development of three-dimensional printing filaments based on poly(lactic acid)/hydroxyapatite composites with potential for tissue engineering

2021 ◽  
pp. 002199832098856
Author(s):  
Marcela Piassi Bernardo ◽  
Bruna Cristina Rodrigues da Silva ◽  
Luiz Henrique Capparelli Mattoso
Keyword(s):  
Tissue Engineering ◽  
Lactic Acid ◽  
Fused Deposition Modeling ◽  
Three Dimensional ◽  
Poly Lactic Acid ◽  
Scanning Calorimetry ◽  
Three Dimensional Printing ◽  
Fused Deposition ◽  
Deposition Modeling ◽  
3D Printed

Injured bone tissues can be healed with scaffolds, which could be manufactured using the fused deposition modeling (FDM) strategy. Poly(lactic acid) (PLA) is one of the most biocompatible polymers suitable for FDM, while hydroxyapatite (HA) could improve the bioactivity of scaffold due to its chemical composition. Therefore, the combination of PLA/HA can create composite filaments adequate for FDM and with high osteoconductive and osteointegration potentials. In this work, we proposed a different approache to improve the potential bioactivity of 3D printed scaffolds for bone tissue engineering by increasing the HA loading (20-30%) in the PLA composite filaments. Two routes were investigated regarding the use of solvents in the filament production. To assess the suitability of the FDM-3D printing process, and the influence of the HA content on the polymer matrix, thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and scanning electron microscopy (SEM) were performed. The HA phase content of the composite filaments agreed with the initial composite proportions. The wettability of the 3D printed scaffolds was also increased. It was shown a greener route for obtaining composite filaments that generate scaffolds with properties similar to those obtained by the solvent casting, with high HA content and great potential to be used as a bone graft.

scholarly journals Design and Characterization of a Screw Extrusion Hot-End for Fused Deposition Modeling

Molecules ◽  
2021 ◽  
Vol 26 (3) ◽  
pp. 590
Author(s):  
Tim Feuerbach ◽  
Markus Thommes
Keyword(s):  
Vinyl Acetate ◽  
Fused Deposition Modeling ◽  
Ethylene Vinyl Acetate ◽  
Direct Printing ◽  
Fused Deposition ◽  
Screw Extrusion ◽  
Deposition Modeling ◽  
Feedstock Material ◽  
Material Form

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.

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.

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