scholarly journals Searching for Rheological Conditions for FFF 3D Printing with PVC Based Flexible Compounds

Materials ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 178 ◽  
Author(s):  
I. Calafel ◽  
R. H. Aguirresarobe ◽  
M. I. Peñas ◽  
A. Santamaria ◽  
M. Tierno ◽  
...  
Keyword(s):  
3D Printing ◽  
Thermal Degradation ◽  
Small Amplitude ◽  
Relaxation Modulus ◽  
Compression Modulus ◽  
Fused Filament Fabrication ◽  
Small Amplitude Oscillatory Shear ◽  
Poly Vinyl Chloride ◽  
G Ratio

Rheology is proposed as a tool to explore plasticized poly(vinyl chloride) (PVC) formulations to be used in the fused filament fabrication (FFF) 3D printing process and so manufactures flexible and ductile objects by this technique. The viscoelastic origin of success/failure in FFF of these materials is investigated. The analysis of buckling of the filament is based on the ratio between compression modulus and viscosity, but for a correct approach the viscosity should be obtained under the conditions established in the nozzle. As demonstrated by small amplitude oscillatory shear (SAOS) measurements, PVC formulations have a crystallites network that provokes clogging in the nozzle. This network restricts printing conditions, because only vanishes at high temperatures, at which thermal degradation is triggered. It is observed that the analysis of the relaxation modulus G(t) is more performing than the G″/G′ ratio to get conclusions on the quality of layers welding. Models printed according to the established conditions show an excellent appearance and flexibility, marking a milestone in the route to obtain flexible objects by FFF.

scholarly journals How Is Rheology Involved in 3D Printing of Phase-Separated PVC-Acrylate Copolymers Obtained by Free Radical Polymerization

Polymers ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 2070
Author(s):  
Mario Iván Peñas ◽  
Miren Itxaso Calafel ◽  
Roberto Hernández Aguirresarobe ◽  
Manuel Tierno ◽  
José Ignacio Conde ◽  
...  
Keyword(s):  
3D Printing ◽  
Radical Polymerization ◽  
Vinyl Chloride ◽  
Relaxation Modulus ◽  
Continuous Phase ◽  
3D Printer ◽  
Fused Filament Fabrication ◽  
Poly Vinyl Chloride ◽  
Melt Elasticity ◽  
Scanning Electron

New auto-plasticised copolymers of poly(vinyl chloride)-r-(acrylate) and polyvinylchloride, obtained by radical polymerization, are investigated to analyse their capacity to be processed by 3D printing. The specific microstructure of the copolymers gives rise to a phase-separated morphology constituted by poly(vinyl chloride) (PVC) domains dispersed in a continuous phase of acrylate-vinyl chloride copolymer. The analysis of the rheological results allows the suitability of these copolymers to be assessed for use in a screw-driven 3D printer, but not by the fused filament fabrication method. This is due to the high melt elasticity of the copolymers, caused by interfacial tension between phases. A relationship between the relaxation modulus of the copolymers and the interlayer adhesion is established. Under adequate 3D-printing conditions, flexible and ductile samples with good dimensional stability and cohesion are obtained, as is proven by scanning electron microscopy (SEM) and tensile stress-strain tests.

Research of 3D Printing Modes of Feedstock for Metal Injection Molding

2020 ◽  
Vol 992 ◽  
pp. 461-466
Author(s):  
A.Yu. Korotchenko ◽  
D.E. Khilkov ◽  
M.V. Tverskoy ◽  
A.A. Khilkova
Keyword(s):  
3D Printing ◽  
Injection Molding ◽  
Metal Injection Molding ◽  
Small Scale ◽  
Print Quality ◽  
Scale Production ◽  
Fused Filament Fabrication ◽  
Factors Affecting ◽  
The Cost

In this work, to reduce the cost of production of parts using injection molding metal technology (MIM technology), it is proposed to use additive technologies (AT) for the manufacture of green parts. The use of AT allows us to abandon expensive molds and expand the field of use of the MIM of technology in single and small-scale production. For manufacture of green parts, the technology of manufacturing fused filament (Fused Filament Fabrication – FFF) is offered. The original composition of the metal powder mix (feedstock) and the filament manufacturing modes for 3D printing have been developed for the FFF technology. The cost of filament is much lower than its analogs. The factors affecting the print quality of green part are considered. All factors are divided into two groups depending on the possibility of their change during printing. The research of the influence of the coefficient filament supply on the geometry of green parts during 3D printing is presented.

scholarly journals Thermal Analysis by Finite Elements of Hotends for 3D Printing by Fused Filament Fabrication

2021 ◽  
Vol 65 (2) ◽  
pp. 129-133
Author(s):  
Germán Gutiérrez Arias ◽  
Fernando Jiménez Díaz ◽  
Edwin Rúa Ramírez ◽  
Jorge Valcarcel Guzman
Keyword(s):  
Thermal Analysis ◽  
Finite Elements ◽  
3D Printing ◽  
Flow Analysis ◽  
Design Parameters ◽  
Design Criteria ◽  
Fused Filament Fabrication ◽  
Design Elements ◽  
Chamber Volume

Nowadays, 3D printing Fused Filament Fabrication (FFF) currently presents obstacles to achieve high printing speeds, mainly due to the inability of the hotend to process the filament fast enough. This article presents the results of the thermodynamic flow analysis carried out on commercial designs of hotends, in the aim intending to identify the design parameters with a higher incidence in the mass flow of material output, so therefore, in the speed and quality of printing. Finite elements thermal analysis was carried out performed in order to characterize the effect of the materials and geometric design elements of the hotends. In this analysis the behavior of the commercial, the commercial melters' behavior and the effects caused by the changes in geometry and materials were obtained. The control variables were the chamber volume and the glass transition volume of each model. These results will be used as the design criteria of a new hotend.

3D Printed Injection Molds Using Various 3D Printing Technologies

2020 ◽  
Vol 1005 ◽  
pp. 150-156 ◽  
Author(s):  
John Ryan Cortez Dizon ◽  
Arnaldo D. Valino ◽  
Lucio R. Souza ◽  
Alejandro H. Espera ◽  
Qiyi Chen ◽  
...  
Keyword(s):  
3D Printing ◽  
Injection Molding ◽  
Polylactic Acid ◽  
Dimensional Accuracy ◽  
Damage Mechanism ◽  
Molding Machine ◽  
Fused Filament Fabrication ◽  
Commercial Software ◽  
3D Printed

This paper explores the possibility of using different 3d printing methods and materials in the production of polymer molds for injection molding applications. A mold producing a cube was designed using a commercial software. Following the standard 3d printing process, injection molds which could produce a cube were printed using different 3d printing materials and 3d printing technologies. The 3d printing technologies used were Stereolithography (SLA), Polyjet and Fused Filament Fabrication (FFF). A bench-top injection molding machine was used to inject polylactic acid (PLA) in these molds. The quality of the injected parts in terms of dimensional accuracy has been investigated. In some cases, the damage mechanism of the polymer molds has also been observed.

Biomimetic Design of 3D Printed Tissue-engineered bone Constructs

2020 ◽  
Vol 16 ◽  
Author(s):  
Wei Liu ◽  
Shifeng Liu ◽  
Yunzhe Li ◽  
Peng Zhou ◽  
Qian ma
Keyword(s):  
Tissue Engineering ◽  
3D Printing ◽  
Advanced Materials ◽  
Bionic Design ◽  
Material Interfaces ◽  
Precise Control ◽  
Cell Printing ◽  
Biomimetic Scaffolds ◽  
3D Printed

Abstract:: Surgery to repair damaged tissue, which is caused by disease or trauma, is being carried out all the time, and a desirable treatment is compelling need to regenerate damaged tissues to further improve the quality of human health. Therefore, more and more research focus on exploring the most suitable bionic design to enrich available treatment methods. 3D-printing, as an advanced materials processing approach, holds promising potential to create prototypes with complex constructs that could reproduce primitive tissues and organs as much as possible or provide appropriate cell-material interfaces. In a sense, 3D printing promises to bridge between tissue engineering and bionic design, which can provide an unprecedented personalized recapitulation with biomimetic function under the precise control of the composition and spatial distribution of cells and biomaterials. This article describes recent progress in 3D bionic design and the potential application prospect of 3D printing regenerative medicine including 3D printing biomimetic scaffolds and 3D cell printing in tissue engineering.

scholarly journals The Direct 3D Printing of Functional PEEK/Hydroxyapatite Composites via a Fused Filament Fabrication Approach

Polymers ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 545
Author(s):  
Krzysztof Rodzeń ◽  
Preetam K. Sharma ◽  
Alistair McIlhagger ◽  
Mozaffar Mokhtari ◽  
Foram Dave ◽  
...  
Keyword(s):  
Tensile Strength ◽  
3D Printing ◽  
Selective Laser Sintering ◽  
Fused Filament Fabrication ◽  
Bone Apposition ◽  
Innovative Solutions ◽  
3D Printed ◽  
Work Samples ◽  
Viable Approach ◽  
Crystalline Domains

The manufacture of polyetheretherketone/hydroxyapatite (PEEK/HA) composites is seen as a viable approach to help enhance direct bone apposition in orthopaedic implants. A range of methods have been used to produce composites, including Selective Laser Sintering and injection moulding. Such techniques have drawbacks and lack flexibility to manufacture complex, custom-designed implants. 3D printing gets around many of the restraints and provides new opportunities for innovative solutions that are structurally suited to meet the needs of the patient. This work reports the direct 3D printing of extruded PEEK/HA composite filaments via a Fused Filament Fabrication (FFF) approach. In this work samples are 3D printed by a custom modified commercial printer Ultimaker 2+ (UM2+). SEM-EDX and µCT analyses show that HA particles are evenly distributed throughout the bulk and across the surface of the native 3D printed samples, with XRD highlighting up to 50% crystallinity and crystalline domains clearly observed in SEM and HR-TEM analyses. This highlights the favourable temperature conditions during 3D printing. The yield stress and ultimate tensile strength obtained for all the samples are comparable to human femoral cortical bone. The results show how FFF 3D printing of PEEK/HA composites up to 30 wt% HA can be achieved.

Fused Filament Fabrication 3D Printed Polylactic Acid Electroosmotic Pumps

Lab on a Chip ◽  
2021 ◽  
Author(s):  
Liang Wu ◽  
Stephen Beirne ◽  
Joan-Marc Cabot Canyelles ◽  
Brett Paull ◽  
Gordon G. Wallace ◽  
...  
Keyword(s):  
Additive Manufacturing ◽  
3D Printing ◽  
Polylactic Acid ◽  
Fused Filament Fabrication ◽  
Flexible Approach ◽  
Electroosmotic Pump ◽  
3D Printed ◽  
Electroosmotic Pumps

Additive manufacturing (3D printing) offers a flexible approach for the production of bespoke microfluidic structures such as the electroosmotic pump. Here a readily accessible fused filament fabrication (FFF) 3D printing...

scholarly journals Gaining a better understanding of the extrusion process in fused filament fabrication 3D printing: a review

2021 ◽  
Author(s):  
Bahaa Shaqour ◽  
Mohammad Abuabiah ◽  
Salameh Abdel-Fattah ◽  
Adel Juaidi ◽  
Ramez Abdallah ◽  
...  
Keyword(s):  
3D Printing ◽  
Numerical Models ◽  
Extrusion Process ◽  
Analytical Models ◽  
Limiting Factor ◽  
Fused Filament Fabrication ◽  
Promising Tool ◽  
Relevant Work ◽  
3D Printing Technique ◽  
Required Quality

AbstractAdditive manufacturing is a promising tool that has proved its value in various applications. Among its technologies, the fused filament fabrication 3D printing technique stands out with its potential to serve a wide variety of applications, ranging from simple educational purposes to industrial and medical applications. However, as many materials and composites can be utilized for this technique, the processability of these materials can be a limiting factor for producing products with the required quality and properties. Over the past few years, many researchers have attempted to better understand the melt extrusion process during 3D printing. Moreover, other research groups have focused on optimizing the process by adjusting the process parameters. These attempts were conducted using different methods, including proposing analytical models, establishing numerical models, or experimental techniques. This review highlights the most relevant work from recent years on fused filament fabrication 3D printing and discusses the future perspectives of this 3D printing technology.

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