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3DP PEEK implants for chest wall reconstruction
A

B
C

D E F

Figure 3. Bionic costal cartilage made of PEEK. (A) Design of wavy elastic structure; (B) 3DP PEEK wavy structure; (C) FEA results
of different wavy structures; (D) bending test of the wavy structure; (E) tension test of the wavy structure; and (F) the comparison of the
uniaxial stress-strain relationship between the adjustment range of the wavy structures and natural costal cartilages in tensile tests .
[38]
to melting point and denaturation temperature of PEEK properties of PEEK materials are significantly affected by
material. Some 3DP equipment with high temperature the thermal history of the materials (Figure 4B). A heat
(above the melting point of PEEK) print head can print insulation cover (Figure 5A-C) could be added near the
PEEK filaments, which can come from Apium Corp. in 3D printing head nozzle to improve the local environment
Germany, Jugao Corporation in China, etc. temperature near the nozzle, thus improving the uniformity
However, the time for this technology to process of the temperature field in the process of printing to
PEEK products is relatively short, and further theories and improve the ultimate strength and crystallinity of PEEK
results are still needed to prove it . However, there have materials, and the experimental results showed that under
[71]
been corresponding studies on the mechanical properties, the optimal process conditions, the maximum tensile
tensile properties, and thermal processing conditions of strength could reach 75 MPa, and the maximum bending
printed PEEK products [66,40] . strength can reach 120 MPa (Figure 5D-F) . Different
[68]
3.2. Crystallization and mechanical properties ambient temperatures can obtain PEEK material parts with
different crystallinity and mechanical properties in the 3D
regulating printing process. Using the printing room temperature of

As a semi-crystalline polymer material, PEEK’s crystal 140°C combined with post-printing annealing treatment
zone proportion is called crystallinity. The mechanical, (160°C for 30 min, followed by 200°C for 2 h) can
physical, and chemical properties of the crystal zone or the improve the crystallinity and mechanical properties of
amorphous zone are vastly different. The crystallization PEEK material manufactured by FDM, and its tensile

228 International Journal of Bioprinting (2022)–Volume 8, Issue 4