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

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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Ankle-Foot Orthosis Made by 3D Printing Technique and Automated Design Software

Applied Bionics and Biomechanics ◽

10.1155/2017/9610468 ◽

2017 ◽

Vol 2017 ◽

pp. 1-6 ◽

Cited By ~ 15

Author(s):

Yong Ho Cha ◽

Keun Ho Lee ◽

Hong Jong Ryu ◽

Il Won Joo ◽

Anna Seo ◽

...

Keyword(s):

3D Printing ◽

Stress Test ◽

Automated Design ◽

Ease Of Use ◽

Foot Drop ◽

Fused Filament Fabrication ◽

Printing Technique ◽

3D Printed ◽

Design Software ◽

3D Printing Technique

We described 3D printing technique and automated design software and clinical results after the application of this AFO to a patient with a foot drop. After acquiring a 3D modelling file of a patient’s lower leg with peroneal neuropathy by a 3D scanner, we loaded this file on the automated orthosis software and created the “STL” file. The designed AFO was printed using a fused filament fabrication type 3D printer, and a mechanical stress test was performed. The patient alternated between the 3D-printed and conventional AFOs for 2 months. There was no crack or damage, and the shape and stiffness of the AFO did not change after the durability test. The gait speed increased after wearing the conventional AFO (56.5 cm/sec) and 3D-printed AFO (56.5 cm/sec) compared to that without an AFO (42.2 cm/sec). The patient was more satisfied with the 3D-printed AFO than the conventional AFO in terms of the weight and ease of use. The 3D-printed AFO exhibited similar functionality as the conventional AFO and considerably satisfied the patient in terms of the weight and ease of use. We suggest the possibility of the individualized AFO with 3D printing techniques and automated design software.

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Generation of Wholly Thermoplastic Composites and Their Processing in Additive Manufacturing

10.31224/osf.io/wnxqj ◽

2021 ◽

Author(s):

Tianran Chen

Keyword(s):

Mechanical Properties ◽

3D Printing ◽

High Performance ◽

Liquid Crystalline ◽

Mechanical Performance ◽

Crystalline Polymer ◽

Extrusion Process ◽

Thermoplastic Composites ◽

Fiber Reinforced ◽

Fused Filament Fabrication

3D printing has attracted great interest over the past three decades due to its high precision, less waste generation and design freedom [1-3]. One of the major challenges 3D printing is the poor mechanical performance of pure polymer parts. Researchers used traditional carbon and glass fiber reinforced composites to overcome this issue [4-7]. The traditional fibers can improve the mechanical properties of printed parts. However, the manufacturing techniques and printing process restrict the overall performance of the printed parts. Thermotropic liquid crystalline polymer (TLCP) is another reinforcement which offers lighter weight, lower viscosity, excellent mechanical performance and great recyclability [8-15]. TLCPs are capable of forming extended conformations when subjected to extensional or shear deformation.[16, 17] The formation of highly orientated molecular structure enables the generation of high mechanical properties. In this study, polyamide was reinforced with TLCP by the dual-extrusion technique to generate high performance composite filaments [18]. Rheological tests were used to optimize the processing conditions of the dual-extrusion process, which could minimize the degradation of matrix polymer. High performance and lightweight fiber-reinforced composite parts were fabricated by utilizing the fused filament fabrication (FFF) technique. The composite filaments were printed at the temperature below the melting point of TLCP to avoid the relaxation of TLCP. The mechanical performances of printed parts are greater than 3D printed parts which are reinforced by conventional fibers.

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Generation of Wholly Thermoplastic Composites and Their Processing in Additive Manufacturing

10.31234/osf.io/4y58z ◽

2021 ◽

Author(s):

Tianran Chen ◽

Donald Baid

Keyword(s):

Mechanical Properties ◽

3D Printing ◽

High Performance ◽

Liquid Crystalline ◽

Mechanical Performance ◽

Crystalline Polymer ◽

Extrusion Process ◽

Thermoplastic Composites ◽

Fiber Reinforced ◽

Fused Filament Fabrication

3D printing has attracted great interest over the past three decades due to its high precision, less waste generation and design freedom[1-3]. One of the major challenges 3D printing is the poor mechanical performance of pure polymer parts. Researchers used traditional carbon and glass fiber reinforced composites to overcome this issue [4-7]. The traditional fibers can improve the mechanical properties of printed parts. However, the manufacturing techniques and printing process restrict the overall performance of the printed parts. Thermotropic liquid crystalline polymer (TLCP) is another reinforcement which offers lighter weight, lower viscosity, excellent mechanical performance and great recyclability [8-15]. TLCPs are capable of forming extended conformations when subjected to extensional or shear deformation.[16, 17] The formation of highly orientated molecular structure enables the generation of high mechanical properties . In this study, polyamide was reinforced with TLCP by the dual-extrusion technique to generate high performance composite filaments [18]. Rheological tests were used to optimize the processing conditions of the dual-extrusion process, which could minimize the degradation of matrix polymer. High performance and lightweight fiber-reinforced composite parts were fabricated by utilizing the fused filament fabrication (FFF) technique. The composite filaments were printed at the temperature below the melting point of TLCP to avoid the relaxation of TLCP. The mechanical performances of printed parts are greater than 3D printed parts which are reinforced by conventional fibers.

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Investigation of mechanical and fracture behavior of pure and carbon fiber reinforced ABS samples processed by fused filament fabrication process

Rapid Prototyping Journal ◽

10.1108/rpj-11-2020-0296 ◽

2021 ◽

Vol ahead-of-print (ahead-of-print) ◽

Author(s):

Cem Boğa

Keyword(s):

Mechanical Properties ◽

Carbon Fiber ◽

3D Printing ◽

Mixed Mode ◽

Fracture Behavior ◽

Production Method ◽

Fused Filament Fabrication ◽

Content Type ◽

Printing Technique ◽

3D Printing Technique

Purpose Acrylonitrile butadiene styrene (ABS), as a light and high strength thermoplastic polymer, has found extensive applications in different industries. Fused filament fabrication, known as three-dimensional (3D) printing technique is considered a rapid prototyping technique that is frequently applied for production of samples of ABS material. Therefore, the purpose of this study is to investigate the mechanical and fracture behavior of such materials and the techniques to improve such properties. Design/methodology/approach Experimental and numerical analyses have been conducted to investigate the effects of internal architecture and chopped carbon fiber (CF) fillers on the mechanical properties and mixed mode fracture behavior of the ABS samples made by 3D printing technique. Four different filling types at 70% filling ratios have been used to produce tensile and special fracture test samples with pure and CF filled ABS filaments (CF-ABS) using 3D process. A special fixture has been developed to apply mixed mode loading on fracture samples, and finite element analyses have been conducted to determine the geometric function of such samples at different loading angles. Findings It has been determined that the printing pattern has a significant effect on the mechanical properties of the sample. The addition of 15% CF to pure ABS resulted in a significant increase in tensile strength of 46.02% for line filling type and 15.04% for hexagon filling type. It has been determined that as the loading angle increases from 0° to 90°, the KIC value decreases. The addition of 15% CF increased the KIC values for hexagonal and line filling type by 64.14% and 12.5%, respectively. Originality/value The damage that will occur in ABS samples produced in 3D printers depends on the type, amount, filling speed, filling type, filling ratio, filling direction and mechanical properties of the additives. All these features are clearly dependent on the production method. Even if the same additive is used, the production method difference shows different microstructural parameters, especially different mechanical properties.

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Microfluidics as a Platform for the Analysis of 3D Printing Problems

Materials ◽

10.3390/ma12172839 ◽

2019 ◽

Vol 12 (17) ◽

pp. 2839 ◽

Cited By ~ 2

Author(s):

Rui Mendes ◽

Paola Fanzio ◽

Laura Campo-Deaño ◽

Francisco J. Galindo-Rosales

Keyword(s):

Fluid Flow ◽

3D Printing ◽

Flow Problem ◽

Numerical Models ◽

Flow Behavior ◽

Layer By Layer ◽

Actual Behavior ◽

Fused Filament Fabrication ◽

Back Flow ◽

Elasticity Number

Fused Filament Fabrication is an extrusion deposition technique in which a thermoplastic filament is melted, pushed through a nozzle and deposited to build, layer-by-layer, custom 3D geometries. Despite being one of the most widely used techniques in 3D printing, there are still some challenges to be addressed. One of them is the accurate control of the extrusion flow. It has been shown that this is affected by a reflux upstream the nozzle. Numerical models have been proposed for the explanation of this back-flow. However, it is not possible to have optical access to the melting chamber in order to confirm the actual behavior of this annular meniscus. Thus, microfluidics seems to be an excellent platform to tackle this fluid flow problem. In this work, a microfluidic device mimicking the 3D printing nozzle was developed, to study the complex fluid-flow behavior inside it. The principal aim was to investigate the presence of the mentioned back-flow upstream the nozzle contraction. As the microfluidic chip was fabricated by means of soft-lithography, the use of polymer melts was restricted due to technical issues. Thus, the working fluids consisted of two aqueous polymer solutions that allowed replicating the printing flow conditions in terms of Elasticity number and to develop a D e – R e flow map. The results demonstrate that the presence of upstream vortices, due to the elasticity of the fluid, is responsible for the back-flow problem.

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A hybrid additive manufacturing platform based on fused filament fabrication and direct ink writing techniques for multi-material 3D printing

The International Journal of Advanced Manufacturing Technology ◽

10.1007/s00170-021-06891-0 ◽

2021 ◽

Author(s):

Thibaut Cadiou ◽

Frédéric Demoly ◽

Samuel Gomes

Keyword(s):

Additive Manufacturing ◽

3D Printing ◽

Fused Filament Fabrication ◽

Direct Ink Writing ◽

Manufacturing Platform

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

Polymers ◽

10.3390/polym13040545 ◽

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.

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Fused Filament Fabrication 3D Printed Polylactic Acid Electroosmotic Pumps

Lab on a Chip ◽

10.1039/d1lc00452b ◽

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...

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Effects of 3D Printing-Line Directions for Stretchable Sensor Performances

Materials ◽

10.3390/ma14071791 ◽

2021 ◽

Vol 14 (7) ◽

pp. 1791

Author(s):

Chi Cuong Vu ◽

Thanh Tai Nguyen ◽

Sangun Kim ◽

Jooyong Kim

Keyword(s):

3D Printing ◽

Thermoplastic Polyurethane ◽

Three Dimensional ◽

Optimal Solution ◽

Human Motion ◽

Repeated Measurements ◽

Fused Filament Fabrication ◽

And Performance ◽

The Times ◽

Stretchable Sensors

Health monitoring sensors that are attached to clothing are a new trend of the times, especially stretchable sensors for human motion measurements or biological markers. However, price, durability, and performance always are major problems to be addressed and three-dimensional (3D) printing combined with conductive flexible materials (thermoplastic polyurethane) can be an optimal solution. Herein, we evaluate the effects of 3D printing-line directions (45°, 90°, 180°) on the sensor performances. Using fused filament fabrication (FDM) technology, the sensors are created with different print styles for specific purposes. We also discuss some main issues of the stretch sensors from Carbon Nanotube/Thermoplastic Polyurethane (CNT/TPU) and FDM. Our sensor achieves outstanding stability (10,000 cycles) and reliability, which are verified through repeated measurements. Its capability is demonstrated in a real application when detecting finger motion by a sensor-integrated into gloves. This paper is expected to bring contribution to the development of flexible conductive materials—based on 3D printing.

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