The Surface Characteristics, Microstructure and Mechanical Properties of PEEK Printed by Fused Deposition Modeling with Different Raster Angles

Abstract

Additive manufacturing provides a novel and robust way to prepare medical product with anatomic matched geometry and tailored mechanical performance. In this study, the surface characteristics, microstructure, and mechanical properties of fused deposition modeling (FDM) prepared polyether-ether-ketone (PEEK) were systematically studied. During the FDM process, the crystal unit cell and thermal attribute of PEEK material remained unchanged, whereas the surface layer generally became more hydrophilic with an obvious reduction in surface hardness. Raster angle has a significant effect on the mechanical strength but not on the failure mechanism. In practice, FDM fabricated PEEK acted more like a laminate rather than a unified structure. Its main failure mechanism was correlated to the internal voids. The results show that horizontal infill orientation with 30° raster angle is promising for a better comprehensive mechanical performance, and the corresponding tensile, flexural, and shear strengths are (76.5 ± 1.4) MPa, (149.7 ± 3.0) MPa, and (55.5 ± 1.8) MPa, respectively. The findings of this study provide guidelines for FDM-PEEK to enable its realization in applications such as orthopedic implants.

Mechanical Properties of Fused Deposition Modeling of Polyetheretherketone (PEEK) and Interest for Dental Restorations: A Systematic Review

“…Several parameters influence the printing of PEEK via FDM technology and, thus, its mechanical properties: the layer thickness [ 21 , 22 , 23 , 24 , 25 , 26 ], the nozzle diameter [ 27 ], the printing speed [ 23 , 27 ], the printing temperature [ 22 , 23 , 24 , 27 , 28 , 29 ], the chamber temperature [ 28 , 30 , 31 ], the raster angle [ 21 , 24 , 25 , 26 , 32 , 33 ], the build plate orientation [ 16 , 24 , 34 , 35 ], the infill rate [ 35 ], the PEEK modifications [ 34 , 36 , 37 ] and the possible post-treatment [ 25 , 31 , 36 , 38 ].…”

“…Among the 18 studies included, 4 exhibited a low risk of bias [ 35 , 39 , 40 , 41 ], 14 showed a moderate risk [ 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 33 , 34 , 35 ] and none exhibited a high risk of bias ( Table 2 , Figure 2 ). Studies were badly scored in relation to the blinding of the tests and the calculation of sample size or allocation, whereas all studies [ 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 36 , 37 , 38 ] except one [ 35 ] were found to be adequate in regard to the presence of a control group.…”

“…The raster angle had even more of an influence on the flexural strength than the layer thickness [ 21 ]. Similarly, the best tensile (82 MPa) and flexural (149.7 MPa) strength values were obtained for the samples printed with a raster angle of 0° compared to 90° [ 32 ] and alternating 0/90° angles [ 33 ]. However, the raster angle alternating between 0 and 90° displayed the highest flexural modulus (2.4 GPa) as compared to raster angles of 90° (2 GPa) and 0° (1.9 GPa) [ 33 ].…”

“…Similarly, Arif et al obtained the best mechanical properties with a raster angle of 0°, with a tensile strength of 82.58 MPa, a flexural strength of 142 MPa and a flexural modulus of 3.08 GPa. Under this condition, the PEEK elements demonstrated 75% and 85% flexural and tensile strengths of those of the molded PEEK, respectively [ 24 , 32 ]. This raster angle induced a good interfacial adhesion and dimensional stability [ 25 ].…”

Additive manufacturing of polyetheretherketone and its composites: A review

“…The samples printed with 100% infill density had better mechanical properties than samples with infill less than 100%. [94,95] Extrusion and printing speed are crucial factors in the FDM of PEEK. Studies have reported the effect of extrusion and printing speed on the microstructure and dimensions of extruded PEEK in 3D printing.…”