Fused deposition modelling (FDM) is one of the fastest-growing additive manufacturing methods used in printing fibre-reinforced composites (FRC). The performances of the resulting printed parts are limited compared to those by other manufacturing methods due to their inherent defects. Hence, the effort to develop treatment methods to overcome these drawbacks has accelerated during the past few years. The main focus of this study is to review the impact of those defects on the mechanical performance of FRC and therefore to discuss the available treatment methods to eliminate or minimize them in order to enhance the functional properties of the printed parts. As FRC is a combination of polymer matrix material and continuous or short reinforcing fibres, this review will thoroughly discuss both thermoplastic polymers and FRCs printed via FDM technology, including the effect of printing parameters such as layer thickness, infill pattern, raster angle and fibre orientation. The most common defects on printed parts, in particular, the void formation, surface roughness and poor bonding between fibre and matrix, are explored. An inclusive discussion on the effectiveness of chemical, laser, heat and ultrasound treatments to minimize these drawbacks is provided by this review.

FDM-Based 3D Printing of Polymer and Associated Composite: A Review on Mechanical Properties, Defects and Treatments.

Fused filament fabrication (FFF), one of the most promising additive manufacturing (AM) methods has attracted considerable attention to date. Although FFF is evolving into a manufacturing tool with significant technological and material advancements, there remains a challenge to transfer FFF-printed parts into functional objects for practical applications. Polymer components fabricated by FFF technique exhibit weak and anisotropic mechanical properties compared to their counterparts by conventional processing. The limited mechanical property for the FFF-printed parts is a result of weak interlayer bond interface that develops during the layer-wise deposition process. This review documents recent advances on the bond interface in FFF-printed parts in aspects of its mechanisms, characterization and enhancement methods. The main objective is to provide a comprehensive understanding of the process-structure-properties of interlayer bond in FFF technique.

Fused filament fabrication of polymer materials: A review of interlayer bond

Additive Manufacturing (AM) is the significantly progressing field in terms of methods, materials, and performance of fabricated parts. Periodical evaluation on the understanding of AM processes and its evolution is needed since the field is growing rapidly. To address this requirement, this paper presents a detailed review of the Additive Manufacturing (AM) methods, materials used, and challenges associated with them. A critical review of the state of art materials in the categories such as metals and alloys, polymers, ceramics, and biomaterials are presented along with their applications, benefits, and the problems associated with the formation of microstructures, mechanical properties, and controlling process parameters. The perspectives and the status of different materials on the fabrication of thin-walled structures using AM techniques have also been discussed. Additionally, the main challenges with AM techniques such as inaccuracy, surface quality, reinforcement distribution, and other common problems identified from the literature are presented. On the whole, this paper provides a comprehensive outlook on AM techniques, challenges, and future research directions.

Methods and materials for additive manufacturing: A critical review on advancements and challenges

In this chapter, an overview of the basic principles of fused deposition modelling, commonly known as 3D printing technology, is presented. The chapter begins by introducing the holistic concept of additive manufacturing and its scientific principle as the technology for the modern and future industry. Then, the science of 3D printing is described. The applications of FDM in various fields are also highlighted with a focus on an interesting role the 3D printing technology is playing in the fight against Covid-19 pandemic. The chapter also gives a highlight of the parameters involved in fused deposition modelling of polymers and their basic interaction with the properties of the manufactured components. In relation to the process parameters, quality aspects of FDM products have also been briefly described in the chapter.

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Basics of Fused Deposition Modelling (FDM)

Three-dimensional (3D) printing is becoming a booming technology to fabricate scaffolds, orthoses, and prosthetic devices for tissue engineering, regenerative medicine, and rehabilitation for patients with disabling neurological diseases (such as amyotrophic lateral sclerosis, traumatic brain injuries, and spinal cord injuries). This is due to the potential of 3D printing to provide patient-specific designs, high structural complexity, and rapid on-demand fabrication at a low-cost. However, one of the major bottlenecks that limits the widespread acceptance of 3D printing for biomedical manufacturing is the lack of polymers, biomaterials, hydrogels, and bioinks functional for 3D printing, biocompatible, and more performing from the biomechanical point of view to meet the different needs. As a matter of fact the field is still struggling with processing of such materials into self-supporting devices with tunable biomechanics, optimal structures, degradation, and bioactivity. Here, will be highlighted all recent advances that have been made in the field of 3D printing in biomedicine, analyzing the polymers, hydrogels, and bioinks, according to their printability, ease of processability, cost, and properties such as mechanics, biocompatibility, and degradation rate. Finally, future considerations for 3D bio-fabrication will be discussed.

Polymeric biomaterials for 3D printing in medicine: An overview

Due to the rapid growth of 3D printing popularity, including fused deposition modeling (FDM), as one of the most common technologies, the proper understanding of the process and influence of its parameters on resulting products is crucial for its development. One of the most crucial parameters of FDM printing is the raster angle and mutual arrangement of the following filament layers. Presented research work aims to evaluate different raster angles (45°, 55°, 55'°, 60° and 90°) on the static, as well as rarely investigated, dynamic mechanical properties of 3D printed acrylonitrile butadiene styrene (ABS) materials. Configuration named 55'° was based on the optimal winding angle in filament-wound pipes, which provides them exceptional mechanical performance and durability. Also in the case of 3D printed samples, it resulted in the best impact strength, comparing to other raster angles, despite relatively weaker tensile performance. Interestingly, all 3D printed samples showed surprisingly high values of impact strength considering their calculated brittleness, which provides new insights into understanding the mechanical performance of 3D printed structures. Simultaneously, it proves that, despite extensive research works related to FDM technology, there is still a lot of investigation required for a proper understanding of this process.

Static and Dynamic Mechanical Properties of 3D Printed ABS as a Function of Raster Angle.

Polyoxymethylene (POM) is one of the most popular thermoplastic polymers used in the industry Therefore, the interest in its potential applications in rapid prototyping is understandable Nevertheless, its low dimensional stability causes the warping of 3D prints, limiting its applications This research aimed to evaluate the effects of POM modification with ethylene-vinyl acetate (EVA) (25, 50, and 75 wt%) on its processing (by melt flow index), structure (by X-ray microcomputed tomography), and properties (by static tensile tests, surface resistance, contact angle measurements, differential scanning calorimetry, and thermogravimetric analysis), as well as very rarely analyzed emissions of volatile organic compounds (VOCs) (by headspace analysis) Performed modifications decreased stiffness and strength of the material, simultaneously enhancing its ductility, which simultaneously increased the toughness even by more than 50% for 75 wt% EVA loading Such an effect was related to an improved linear flow rate resulting in a lack of defects inside the samples The decrease of the melting temperature and the slight increase of thermal stability after the addition of EVA broadened the processing window for 3D printing The 3D printing trials on two different printers showed that the addition of EVA copolymer increased the possibility of a successful print without defects, giving space for further development

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Mateusz Galeja

Papers

Static and Dynamic Mechanical Properties of 3D Printed ABS as a Function of Raster Angle.

POM/EVA Blends with Future Utility in Fused Deposition Modeling.