scholarly journals Fused Deposition Modeling of Polyamides: Crystallization and Weld Formation

Polymers ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 2980
Author(s):  
Andrea Costanzo ◽  
Umberto Croce ◽  
Roberto Spotorno ◽  
Seif Eddine Fenni ◽  
Dario Cavallo
Keyword(s):  
3D Printing ◽  
Crystallization Kinetics ◽  
Fused Deposition Modeling ◽  
Degree Of Crystallinity ◽  
Temperature History ◽  
Weld Strength ◽  
Processing Conditions ◽  
Scanning Calorimetry ◽  
Fused Deposition ◽  
Deposition Modeling

International newspapers and experts have called 3D printing the industrial revolution of this century. Among all its available variants, the fused deposition modeling (FDM) technique is of greater interest since its application is possible using simple desktop printers. FDM is a complex process, characterized by a large number of parameters that influence the quality and final properties of the product. In particular, in the case of semicrystalline polymers, which afford better mechanical properties than amorphous ones, it is necessary to understand the crystallization kinetics as the processing conditions vary, in order to be able to develop models that allow having a better control over the process and consequently on the final properties of the material. In this work it was proposed to study the crystallization kinetics of two different polyamides used for FDM 3D printing and to link it to the microstructure and properties obtained during FDM. The kinetics are studied both in isothermal and fast cooling conditions, thanks to a home-built device which allows mimicking the quenching experienced during filament deposition. The temperature history of a single filament is then determined by mean of a micro-thermocouple and the final crystallinity of the sample printed in a variety of conditions is assessed by differential scanning calorimetry. It is found that the applied processing conditions always allowed for the achievement of the maximum crystallinity, although in one condition the polyamide mesomorphic phase possibly develops. Despite the degree of crystallinity is not a strong function of printing variables, the weld strength of adjacent layers shows remarkable variations. In particular, a decrease of its value with printing speed is observed, linked to the probable development of molecular anisotropy under the more extreme printing conditions.

scholarly journals Influence of Controlled Cooling on Crystallinity of Poly(L-Lactic Acid) Scaffolds after Hydrolytic Degradation

Materials ◽  
2020 ◽  
Vol 13 (13) ◽  
pp. 2943
Author(s):  
Javier Vazquez-Armendariz ◽  
Raquel Tejeda-Alejandre ◽  
Aida Rodriguez-Garcia ◽  
Yadira I. Vega-Cantu ◽  
Christian Mendoza-Buenrostro ◽  
...  
Keyword(s):  
Fused Deposition Modeling ◽  
Cooling System ◽  
Thermo Gravimetric Analysis ◽  
Hydrolytic Degradation ◽  
Degree Of Crystallinity ◽  
Gravimetric Analysis ◽  
Controlled Cooling ◽  
Scanning Calorimetry ◽  
Fused Deposition ◽  
Deposition Modeling

The use of hybrid manufacturing to produce bimodal scaffolds has represented a great advancement in tissue engineering. These scaffolds provide a favorable environment in which cells can adhere and produce new tissue. However, there are several areas of opportunity to manufacture structures that provide enough strength and rigidity, while also improving chemical integrity. As an advancement in the manufacturing process of scaffolds, a cooling system was introduced in a fused deposition modeling (FDM) machine to vary the temperature on the printing bed. Two groups of polylactic acid (PLA) scaffolds were then printed at two different bed temperatures. The rate of degradation was evaluated during eight weeks in Hank’s Balanced Salt Solution (HBSS) in a controlled environment (37 °C–120 rpm) to assess crystallinity. Results showed the influence of the cooling system on the degradation rate of printed scaffolds after the immersion period. This phenomenon was attributable to the mechanism associated with alkaline hydrolysis, where a higher degree of crystallinity obtained in one group induced greater rates of mass loss. The overall crystallinity was observed, through differential scanning calorimetry (DSC), thermo gravimetric analysis (TGA), and Fourier transformed infrared spectroscopy (FTIR) analysis, to increase with time because of the erosion of some amorphous parts after immersion.

Biodegradable 3D Printed Polymer Microneedles for Transdermal Drug Delivery

2018 ◽  
Author(s):  
Michael A. Luzuriaga ◽  
Danielle R. Berry ◽  
John C. Reagan ◽  
Ronald A. Smaldone ◽  
Jeremiah J. Gassensmith
Keyword(s):  
Drug Delivery ◽  
3D Printing ◽  
Transdermal Drug Delivery ◽  
Fused Deposition Modeling ◽  
Fused Deposition ◽  
Modeling Software ◽  
Deposition Modeling ◽  
3D Printed ◽  
Microfabrication Technique ◽  
Mechanical Strengths

Biodegradable polymer microneedle (MN) arrays are an emerging class of transdermal drug delivery devices that promise a painless and sanitary alternative to syringes; however, prototyping bespoke needle architectures is expensive and requires production of new master templates. Here, we present a new microfabrication technique for MNs using fused deposition modeling (FDM) 3D printing using polylactic acid, an FDA approved, renewable, biodegradable, thermoplastic material. We show how this natural degradability can be exploited to overcome a key challenge of FDM 3D printing, in particular the low resolution of these printers. We improved the feature size of the printed parts significantly by developing a post fabrication chemical etching protocol, which allowed us to access tip sizes as small as 1 μm. With 3D modeling software, various MN shapes were designed and printed rapidly with custom needle density, length, and shape. Scanning electron microscopy confirmed that our method resulted in needle tip sizes in the range of 1 – 55 µm, which could successfully penetrate and break off into porcine skin. We have also shown that these MNs have comparable mechanical strengths to currently fabricated MNs and we further demonstrated how the swellability of PLA can be exploited to load small molecule drugs and how its degradability in skin can release those small molecules over time.

scholarly journals 3D Printing of Mini Tablets for Pediatric Use

2021 ◽  
Vol 14 (2) ◽  
pp. 143
Author(s):  
Julius Krause ◽  
Laura Müller ◽  
Dorota Sarwinska ◽  
Anne Seidlitz ◽  
Malgorzata Sznitowska ◽  
...  
Keyword(s):  
3D Printing ◽  
Fused Deposition Modeling ◽  
Dosage Forms ◽  
Small Scale ◽  
Fused Deposition ◽  
On Demand ◽  
Pediatric Diseases ◽  
Deposition Modeling ◽  
Manufacturing Techniques ◽  
Pediatric Use

In the treatment of pediatric diseases, suitable dosages and dosage forms are often not available for an adequate therapy. The use of innovative additive manufacturing techniques offers the possibility of producing pediatric dosage forms. In this study, the production of mini tablets using fused deposition modeling (FDM)-based 3D printing was investigated. Two pediatric drugs, caffeine and propranolol hydrochloride, were successfully processed into filaments using hyprolose and hypromellose as polymers. Subsequently, mini tablets with diameters between 1.5 and 4.0 mm were printed and characterized using optical and thermal analysis methods. By varying the number of mini tablets applied and by varying the diameter, we were able to achieve different release behaviors. This work highlights the potential value of FDM 3D printing for the on-demand production of patient individualized, small-scale batches of pediatric dosage forms.

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.

Influence of Part Orientation on the Surface Roughness in the Process of Fused Deposition Modeling

2021 ◽  
Vol 896 ◽  
pp. 29-37
Author(s):  
Ján Milde ◽  
František Jurina ◽  
Jozef Peterka ◽  
Patrik Dobrovszký ◽  
Jakub Hrbál ◽  
...  
Keyword(s):  
Surface Roughness ◽  
3D Printing ◽  
Fused Deposition Modeling ◽  
Orientation Angle ◽  
Acrylonitrile Butadiene Styrene ◽  
Lower Surface ◽  
Geometrical Model ◽  
Fused Deposition ◽  
Deposition Modeling ◽  
Part Orientation

The article focused on the influence of part orientation on the surface roughness of cuboid parts during the process of fabricating by FDM technology. The components, in this case, is simple cuboid part with the dimensions 15 mm x 15mm x 30 mm. A geometrical model is defined that considers the shape of the material filaments after deposition, to define a theoretical roughness profile, for a certain print orientation angle. Five different print orientations in the X-axis of the cuboid part were set: 0°, 30°, 45°, 60°, and 90°. According to previous research in the field of FDM technology by the author, the internal structure (infill) was set at the value of 70%. The method of 3D printing was the Fused Deposition Modeling (FDM) and the material used in this research was thermoplastic ABS (Acrylonitrile butadiene styrene). For each setting, there were five specimens (twenty five prints in total). Prints were fabricated on a Zortrax M200 3D printer. After the 3D printing, the surface “A” was investigated by portable surface roughness tester Mitutoyo SJ-210. Surface roughness in the article is shown in the form of graphs (Fig.7). Results show increase in part roughness with increasing degree of part orientation. When the direction of applied layers on the measured surface was horizontal, significant improvement in surface roughness was observed. Findings in this paper can be taken into consideration when designing parts, as they can contribute in achieving lower surface roughness values.

Understanding and improving FDM 3D printing to fabricate high-resolution and optically transparent microfluidic devices

Lab on a Chip ◽  
2021 ◽  
Author(s):  
Reverson Fernandes Quero ◽  
Gessica Domingos Silveira ◽  
Jose Alberto Fracassi da Silva ◽  
Dosil Pereira de Jesus
Keyword(s):  
High Resolution ◽  
3D Printing ◽  
Fused Deposition Modeling ◽  
Microfluidic Devices ◽  
Fused Deposition ◽  
Optically Transparent ◽  
Deposition Modeling

The fabrication of microfluidic devices through Fused Deposition Modeling (FDM) 3D printing has faced several challenges, mainly regarding obtaining microchannels with suitable transparency and sizes. Thus, the use of this...

Hochproduktiver fertigungsangepasster 3D-Druck/Productive and manufacturing adjusted 3D printing

2017 ◽  
Vol 107 (07-08) ◽  
pp. 520-523
Author(s):  
J. Prof. Bliedtner ◽  
M. Schilling
Keyword(s):  
3D Printing ◽  
Research And Development ◽  
Fused Deposition Modeling ◽  
Dynamic Properties ◽  
Development Project ◽  
Efficient Production ◽  
Large Format ◽  
Printing Process ◽  
Fused Deposition ◽  
Deposition Modeling

Das FDM (Fused Deposition Modeling)-Verfahren ist aufgrund der Vielzahl von industriellen und privaten Anwendungen gegenwärtig das erfolgreichste 3D-Druck-Verfahren. Ziel des Forschungs- und Entwicklungsprojektes „HP3D“ ist die effiziente Herstellung von großformatigen Bauteilen in einem echten 3D-Verfahren aus frei wählbaren thermoplastischen Kunststoffen. An die Umsetzung des Projekts wurde sehr komplex herangegangen, um zu garantieren, dass die mechanischen und dynamischen Eigenschaften der aufgebauten Teile den konzipierten Eigenschaften entsprechen.   The FDM process is currently the most successful 3D printing process due to the multitude of industrial and private applications. The aim of the research and development project HP3D is the efficient production of large-format components in a real 3D process made of freely selectable thermoplastics. The implementation of the project has been very complex in order to ensure that the mechanical and dynamic properties of the assembled parts correspond to the designed properties.

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