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Optimization of 3D Printing Parameters of PLA/HA Bone Plates

A B C

D E F

G H I

J

Figure 5. (A-J) Cross-sectional shapes of single deposited line of scheme 1-10.
Table 5. Temperature measurement results of outlet/substrate
Scheme Outlet Substrate Temperature
temperature temperature gap (°C)
(°C) (°C)
1 191.6 174.6 17.1
2 167.0 152.8 14.2
3 178.2 174.0 4.2
4 201.2 160.9 40.3
5 190.2 170.8 19.4
6 188.8 159.8 29.0
7 212.6 154.3 58.3
8 202.4 161.8 40.6
9 196.6 146.2 50.4
10 207.9 169.3 38.6
Figure 6. Effect of overlap rate on porosity and flexural strength.
material was conducive to the full fusion of the extruded
the experimental group of PLA/HA filaments were higher material with the surrounding material. The melting point
than those of the PLA filament, and the temperature of
the 20% HA filament was higher. The temperature of the of PLA is 150 – 180°C. The comparison of the optimized
scheme 10 with scheme 9 shows that the temperature on
molten material in the nozzle outlet had little to do with the substrate for scheme 10 reached the melting point
the printing speed, the layer thickness, or the filament range of the PLA. However, the temperature of the
feeding speed. It mainly depended on the temperature of molten material of scheme 9 on the substrate was lower
the nozzle and the properties of the material. With the than the melting point of PLA. Furthermore, the width of
same heating temperature as the nozzle, the HA content the deposited line printed in the optimized scheme 10 was
increased, making it easier for the material to be heated 3.7 times that of scheme 9, which could melt and fuse a
to a higher temperature. After the material was extruded larger area of solidified materials. The temperature of the
from the nozzle, the temperature-drop status of different deposited line printed in scheme 3 on the substrate was
schemes varied, and the temperature drop of the 20% HA the highest among all the parameters, mainly because the
filament was significantly greater than that of the other high filament feeding speed led to more materials being
two materials due to a number of factors. extruded onto the substrate per unit time, resulting in a
When the extruded material reached the substrate (or slow cooling speed within the distance from the nozzle
front layer), a larger high-temperature area of the molten to the substrate. However, because the layer thickness

160 International Journal of Bioprinting (2022)–Volume 8, Issue 1