Citation: Zhang, H.; Lei, X.; Hu, Q.;
Wu, S.; Aburaia, M.; Gonzalez-
Gutierrez, J.; Lammer, H. Hybrid
Printing Method of Polymer and
Continuous Fiber-Reinforced
Thermoplastic Composites
(CFRTPCs) for Pipes through
Double-Nozzle Five-Axis Printer.
Polymers 2022, 14, 819. https://
doi.org/10.3390/polym14040819
Academic Editor: Lilia Sabantina
Received: 1 December 2021
Accepted: 16 February 2022
Published: 20 February 2022
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Article
Hybrid Printing Method of Polymer and Continuous
Fiber-Reinforced Thermoplastic Composites (CFRTPCs) for
Pipes through Double-Nozzle Five-Axis Printer
Haiguang Zhang
1,2,3,
* , Xu Lei
1
, Qingxi Hu
1,2,3
, Shichao Wu
1
, Mohamed Aburaia
4
,
Joamin Gonzalez-Gutierrez
5
and Herfried Lammer
6
1
Rapid Manufacturing Engineering Center, Mechatronic Engineering and Automation of Shanghai University,
Shanghai 200444, China; YamaS@shu.edu.cn (X.L.); huqingxi@shu.edu.cn (Q.H.); seedo@i.shu.edu.cn (S.W.)
2
Shanghai Key Laboratory of Intelligent Manufacturing and Robotics, Shanghai University,
Shanghai 200072, China
3
National Demonstration Center for Experimental Engineering Training Education, Shanghai University,
Shanghai 200444, China
4
Competence Center Digital Manufacturing and Robotics, University of Applied Science Technikum Wien,
Höchstädtplatz 6, 1200 Wien, Austria; aburaia@technikum-wien.at
5
Institute of Polymer Processing, Montanuniversitaet Leoben, Otto Gloeckel-Strasse 2, 8700 Leoben, Austria;
joamin.gonzalez-gutierrez@unileoben.ac.at
6
Kompetenzzentrum Holz GmbH, Altenberger Straße 69, 4040 Linz, Austria; h.lammer@wood-kplus.at
* Correspondence: haiguang_zhang@i.shu.edu.cn
Abstract:
The most widely used 3D process, fused deposition modeling (FDM), has insufficient
interlayer adhesion due to its layer-by-layer forming method. A support material is also essential
for the hollow parts and cantilevers. Moreover, the polymer materials used have limited mechanical
properties. These issues have restricted the application of FDM in high-performance fields. Con-
tinuous fiber-reinforced thermoplastic composites (CFRTPCs) have high mechanical properties and
have recently become the focus of research in the field of 3D printing. This paper, using pipe parts
as an example, proposes a hybrid of pure polymer (pure PLA used) and CFRTPC (flax fiber pre-
impregnated filament) material to develop a printing method based on the outstanding mechanical
properties of CFRTPC material. After studying the printing path planning algorithm, the CFRTPC
filament is laid along the axial and radial directions on the surface of the polymer base to improve
the printed parts’ properties. The method feasibility and algorithm accuracy are verified through the
development of five-axis printing equipment with a double nozzle. Through the printed sample’s
tensile, compression and bending tests, the results show that the tensile, compressive and bending
properties of PLA pipe can be significantly enhanced by laying CFRTPC filament along the axial
and radial directions of the pipe. To summarize, the introduction of CFRTPCs greatly improved
the mechanical properties of the printed parts, and the implementation of our method provides an
effective way to solve the defects of the FDM process.
Keywords: 3D printing; continuous fiber-reinforced; 5-axis printer; printing path
1. Introduction
Three-dimensional printing (3DP), also called additive manufacturing (AM), plays a
key role in high-tech areas such as bioengineering [
1
] and aerospace [
2
] and is increasingly
gaining attention. One of the most popular and widely used AM processes is fused
deposition modeling (FDM) [
3
]. Polylactic acid (PLA) and Acrylonitrile Butadiene Styrene
(ABS) are the most commonly used filaments in FDM because they are cheap, readily
available and environmentally friendly. However, with increasing demands on product
performance, high-performance plastics can also meet the increased requirements, but fiber
materials perform even better. People are therefore turning their attention to composites in
Polymers 2022, 14, 819. https://doi.org/10.3390/polym14040819 https://www.mdpi.com/journal/polymers
