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RESEARCH ARTICLE

Optimization of 3D Printing Parameters of

Biodegradable Polylactic Acid/Hydroxyapatite

Composite Bone Plates

Patiguli Aihemaiti, Houfeng Jiang, Wurikaixi Aiyiti*, Ayiguli Kasimu

School of Mechanical Engineering, Xinjiang University, Urumqi 830000, PR China

Abstract: The building parameters of three-dimensional (3D) printed polylactic acid/hydroxyapatite (HA) composite
bone plates were optimized by an orthogonal experiment, and the effects of the layer thickness, printing speed, filament
feeding speed, and HA content on the bending strengths of the specimens were analyzed. The deformation characteristics
of the specimens were studied by 3D full-field strain analysis, and the internal defects of the specimens were analyzed.
The effects of different combinations of the process parameters on the cross-sectional shape of the single deposited line,
printing temperature, and pressure of the molten material were further analyzed. The results showed that the factors affecting
the bending properties were the layer thickness, printing speed, filament feeding speed, and HA content, successively. The
optimized process parameters were an HA content of 10%, a layer thickness of 0.1 mm, a printing speed of 30 mm/s, and a
filament feeding speed of 0.8 mm/s, and the optimized specimen bending strength was 103.1 ± 5.24 MPa. The deposited line
with a flat section shape and width greater than the print spacing helped to reduce the porosity of the specimens. The process
parameters that resulted in large high-temperature areas and a high extrusion pressure could better promote material fusion.

Keywords: Additive manufacturing; Composite material; Biodegradable bone plate; Orthogonal experiment; Bending strength

*Correspondence to: Wurikaixi Aiyiti, School of Mechanical Engineering, Xinjiang University, Urumqi 830000, PR China; wurikaixi@xju.edu.cn
Received: November 8, 2021; Accepted: November 30, 2021; Published Online: December 17, 2021

Citation: Aihemaiti P, Jiang H, Aiyiti W, et al., 2022, Optimization of 3D Printing Parameters of Biodegradable Polylactic Acid/Hydroxyapatite
Composite Bone Plates. Int J Bioprint, 8(1):490. http:// doi.org/10.18063/ijb.v8i1.490

1. Introduction Metal implant materials have excellent mechanical
properties, but its elastic modulus is much higher than that
Additive manufacturing (AM), also known as three- of human bone and will lead to stress shielding . Unlike
[15]
dimensional (3D) printing or rapid prototyping, has been
widely applied in various fields, including manufacturing, artificial joints, cages, and other implants that do not need
to be removed after implantation into the human body,
medicine, architecture, and art . The combination of
[1]
AM with digital medical imaging technology, reverse metal plates need to be removed after fracture healing to
[16]
engineering, and computer-aided design (CAD) can avoid stress shielding . The ideal plate should realize
provide support for the accurate and customized treatment strong fixation in the early stage of fracture treatment and
of patients based on their individual characteristics . The prevent osteoporosis of the fixed bone induced by stress
[2]
application of AM in orthopedics is the main use of AM shielding in the later stage. If the plate is degradable, it
in the medical field and customized implants are one can degrade and crack gradually with fracture healing,
of the key applications of 3D printing in orthopedics . and the stress shielding effect will gradually decrease
[3]
Orthopedic implants include trauma implants (e.g., plates until it disappears completely, which is conducive to the
and screws) [4,5] , spinal implants (such as artificial vertebral conduction of physiological stress and accelerates the
bodies and cages) , joint implants (e.g., artificial hip formation and reconstruction of bone. At the same time,
[6]
joints and knee joints) [7,8] , personalized prostheses (e.g., it does not need to be removed again through surgery [17,18] .
scapular prosthesis, chest prostheses, and rib prostheses) Polylactic acid (PLA) is a kind of promising polymer
[9-11] , and bone tissue engineering scaffolds [12-14] . for use in various biomedical applications owing to its

© 2021 Author(s). This is an Open Access article distributed under the terms of the Creative Commons Attribution License, permitting distribution and
reproduction in any medium, provided the original work is properly cited.
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