Additive manufacturing of PLA structures using fused deposition modelling: Effect of process parameters on mechanical properties and their optimal selection

An overview on 3D printing technology: Technological, materials, and applications

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.

Recent progress on polymer materials for additive manufacturing

Throughout the world there have been alarming concerns over the use of nonrenewable resources during manufacturing of goods and associated environmental legislations. Therefore, the use of natural materials and fabrication of composites therefrom, particularly, development of natural fiber reinforced polymer composites is gaining significant attention. Although natural fiber reinforced composites (NFRCs) show strong application prospects, various materials and processing related challenges needs to be addressed to achieve long-term stability and performance. In this review, we attempted to provide an overview of different types of natural fibers, their characteristics and properties enabling them to be used as reinforcing agents in different polymers. Then the unique requirement of fiber surface modification to achieve enhanced fiber-matrix bonding is discussed. The article also discusses conventional processing routes and critical issues associated with NFRCs processing. The use of different additive manufacturing (AM) technologies in processing polymer composites is also discussed. At the end, we have critically analyzed the challenges and opportunities associated with AM of NFRCs.

Additive manufacturing of natural fiber reinforced polymer composites: Processing and prospects

Fused deposition modelling (FDM) is a promising additive manufacturing technology and an alternative of conventional processes for the fabrication of fibre reinforced composites due to its ability to build functional parts having complex geometries. Continuous fibre reinforced thermoplastic composites (CFRTPCs) are becoming more significant in industrial applications due to their inherit advantages such as excellent mechanical performance, recycling and potential lightweight structures [1,2]. However, a major concern affecting the efficient use of 3D printed composites is the effect of impact damage on the structural integrity, compared to conventional pre-preg composites. The aim of this study is to evaluate the effect of build orientation, layer thickness and fibre volume content on the impact performance of 3D printed continuous carbon, glass, and Kevlar® fibre reinforced nylon composites, manufactured by FDM technique. Charpy impact tests are carried out to determine impact strength. SEM images of fractured surfaces are examined to assess failure mechanics of the different configurations. It is observed that the effect of layer thickness of nylon samples on the impact performance was different for flat and on-edge samples. Impact strength increases as layer thickness increases in flat samples but, conversely, it decreases in on-edge samples, depicting a more brittle fracture. In addition, the results show that impact strength increases as fibre volume content increases in most cases. Glass fibre reinforced samples exhibits the highest impact strength and carbon fibre reinforced samples the lowest one and similar to nylon performance. Furthermore, on-edge reinforced samples exhibit higher values of impact strength than flat reinforced samples. Finally, the results obtained demonstrate that impact strength exhibited by 3D printed composites are significantly higher than the usual 3D printed thermoplastics and, in some cases, even better than common pre-preg materials.

Impact damage resistance of 3D printed continuous fibre reinforced thermoplastic composites using fused deposition modelling

The application of non-destructive techniques for the evaluation of internal damage in composite materials is a challenge due to their complexity. The aim of this study is to analyse the ability of ultrasonic technique to identify and evaluate manufacturing defects and internal damage in composite laminates. Artificial object inclusions of different shapes, sizes and materials were embedded in carbon fibre reinforced epoxy (CFRP) laminates. Comprehensive investigation of non-destructive evaluation using phased array ultrasonic testing to trace and characterize the embedded defects is presented. Phased array ultrasonic technique was able to precisely locate most of the artificial inclusion in the composite laminates. Nerveless, the shape and size of the inclusions were not accurately determined due to the high signal attenuation and distortion characteristics of the carbon fibre epoxy composite. Furthermore, a major concern affecting the efficient use of composite laminates is their vulnerability to low velocity impact damage. The dynamic behaviour of composite laminates is very complex as there are many concurrent phenomena during composite laminate failure under impact loading. Thus, the practicality of the previous results is demonstrated by the evaluation of impacted carbon fibre reinforced epoxy laminates using ultrasonic testing. The influence of laminate thickness and impact energy on impact damage is also investigated. The performance of phased array ultrasonic testing for the inspection of composite laminates with barely visible impact damage is evaluated. In addition, fibre-reinforced thermoplastic composites are becoming more significant in industrial applications due to their excellent mechanical performance and potential recycling. In this study, impact damage in 3D printed continuous glass fibre reinforced thermoplastic laminates is also analysed. Phased array ultrasonic testing is performed and the amount of damage is quantified in terms of delaminated area.

Internal damage evaluation of composite structures using phased array ultrasonic technique: Impact damage assessment in CFRP and 3D printed reinforced composites

Effect of stacking sequence on Charpy impact and flexural damage behavior of composite laminates

Experimental study of the influence of thickness and ply-stacking sequence on the compression after impact strength of carbon fibre reinforced epoxy laminates

G.P. Rodríguez

Papers

Impact damage resistance of 3D printed continuous fibre reinforced thermoplastic composites using fused deposition modelling

Internal damage evaluation of composite structures using phased array ultrasonic technique: Impact damage assessment in CFRP and 3D printed reinforced composites

Effect of stacking sequence on Charpy impact and flexural damage behavior of composite laminates

Experimental study of the influence of thickness and ply-stacking sequence on the compression after impact strength of carbon fibre reinforced epoxy laminates

Damage resistance of carbon fibre reinforced epoxy laminates subjected to low velocity impact: Effects of laminate thickness and ply-stacking sequence