Enhancing Mechanical Properties of Thin-Walled Structures Using Non-Planar Extrusion Based Additive Manufacturing

2017 ◽  
Author(s):  
Abdullah T. Alsharhan ◽  
Timotei Centea ◽  
Satyandra K. Gupta
Keyword(s):  
Additive Manufacturing ◽  
Fiber Reinforced Composites ◽  
Reinforced Composites ◽  
Continuous Fiber ◽  
3 Dimensional ◽  
Thin Walled Structures ◽  
Significant Interest ◽  
Thin Walled ◽  
Planar Approach ◽  
Am Processes

Traditional extrusion based additive manufacturing (AM) processes build parts by depositing material in planar layers. The development of processes that adopt a non-planar approach is becoming a subject of significant interest in AM research. It is expected that such processes will impart superior mechanical strength to anisotropic and thin-walled structures, and will especially be useful in exploiting continuous fiber reinforced composites in additive manufacturing. This paper presents an extrusion based non-planar additive manufacturing process. The process allows for the deposition of material along 3-dimensional paths, providing the capability to reorient deposition head, build objects on curved platforms, and create complete structures using one continuous strand. Two different parts are fabricated and tested in this paper. One is produced using the developed process, while the other is created using a commercial FDM 3D printer. The two specimens are then mechanically tested to examine their behavior in two different loading configurations, and to investigate the effect that the deposition method and orientation has on the failure mode.

Recent Patents in Additive Manufacturing of Continuous Fiber Reinforced Composites

2019 ◽  
Vol 12 (1) ◽  
pp. 25-36 ◽  
Author(s):  
Chao Hu ◽  
Zeyu Sun ◽  
Yi Xiao ◽  
Qinghua Qin
Keyword(s):  
Additive Manufacturing ◽  
Raw Materials ◽  
Fiber Reinforced Composites ◽  
Reinforced Composites ◽  
Fiber Reinforced ◽  
Continuous Fiber ◽  
Manufacturing Method ◽  
Carbon Fiber Reinforced Composites ◽  
Bending Stresses ◽  
Continuous Carbon Fiber

Background: Additive Manufacturing (AM) enables the accurate fabrication of designed parts in a short time without the need for specific molds and tools. Although polymers are the most widely used raw materials for AM, the products printed by them are inherently weak, unable to sustain large tension or bending stresses. A need for the manufacturing of fiber reinforced composites, especially continuous fiber as reinforcement, has attracted great attention in recent years. Objective: Identifying the progress of the AM of continuous carbon fiber reinforced composites over time and therefore establishing a foundation on which current research can be based. Methods: Elaborating the most related patents regarding the AM techniques for fabricating continuous fiber reinforced composites in the top three institutions, including Markforged company, Xi’an Jiaotong University and President and Fellows of Harvard College. Results: The recent patents in AM of continuous fiber reinforced composites are classified into two aspects: patents related to novel technique methods and patents related to novel structures. The current issues and future development of AM-based composites are given. Conclusion: New structures and techniques have been introduced into conventional 3D printers to enable the printing of continuous fiber reinforced composites. However, until now, Markforged is the only company commercializing the fabrication of this kind of composites based on AM technique. Numerous challenges and issues need to be solved so that AM of continuous fiber reinforced composites can be a new manufacturing method.

Feasibility and Characterization of Large-Scale Additive Manufacturing With Long Fiber Reinforced Composites

2020 ◽  
Author(s):  
Aditya R. Thakur ◽  
Ming C. Leu ◽  
Xiangyang Dong
Keyword(s):  
Additive Manufacturing ◽  
Carbon Fiber ◽  
Carbon Fibers ◽  
Large Scale ◽  
Flexural Modulus ◽  
High Deposition Rate ◽  
Reinforced Composites ◽  
Fiber Reinforced ◽  
Continuous Fiber ◽  
Long Carbon Fibers

Abstract A new additive manufacturing (AM) approach to fabricate long fiber reinforced composites (LFRC) was proposed in this study. A high deposition rate was achieved by the implementation of a single-screw extruder, which directly used thermoplastic pellets and continuous fiber tows as feedstock materials. Thus, the proposed method was also used as a large-scale additive manufacturing (LSAM) method for printing large-volume components. Using polylactic acid (PLA) pellets and continuous carbon fiber tows, the feasibility of the proposed AM method was investigated through printing LFRC samples and further demonstrated by fabricating large-volume components with complex geometries. The printed LFRC samples were compared with pure thermoplastic and continuous fiber reinforced composite (CFRC) counterparts via mechanical tests and microstructural analyses. With comparable flexural modulus, the flexural strength of the LFRC samples was slightly lower than that of the CFRC samples. An average improvement of 28% in flexural strength and 50% in flexural modulus were achieved compared to those of pure PLA parts, respectively. Discontinuous long carbon fibers, with an average fiber length of 20.1 mm, were successfully incorporated into the printed LFRC samples. The carbon fiber orientation, distribution of carbon fiber length, and dispersion of carbon fiber as well as porosity were further studied. The carbon fibers were highly oriented along the printing direction with a relatively uniformly distributed fiber reinforcement across the LFRC cross section. With high deposition rate (up to 0.8 kg/hr) and low material costs (< $10/kg), this study demonstrated the potentials of the proposed printing method in LSAM of high strength polymer composites reinforced with long carbon fibers.

Future requirements in the characterization of continuous fiber-reinforced polymeric composites (IUPAC Technical Report)

2002 ◽  
Vol 74 (4) ◽  
pp. 601-628 ◽  
Author(s):  
D. R. Moore ◽  
A. J. Cervenka
Keyword(s):  
Mechanical Properties ◽  
Fiber Reinforced Composites ◽  
Reinforced Composites ◽  
Fiber Reinforced ◽  
Continuous Fiber ◽  
Interfacial Effects ◽  
Technical Report ◽  
Processing Properties ◽  
Historic Background

Characterization of continuous fiber-reinforced composites is examined in terms of processing, properties, and structure. Five processing and five property topics are then examined in terms of reviewing some of the historic background in these areas with the aim of identifying current issues and requirements for the future. The topics covered in the processing section are: polymeric matrix, impregnation, interfacial effects, residual stresses, and pre-preg tack. In the mechanical properties section the topics are: choice of standard, recycling and reusability, durability, environmental strength, and toughness. The paper provides a ten-point plan for future requirements.

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