Does annealing improve the interlayer adhesion and structural integrity of FFF 3D printed PEEK lumbar spinal cages?
Does annealing improve the interlayer adhesion and structural integrity of FFF 3D printed PEEK lumbar spinal cages?
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DOI：
10.1016/j.jmbbm.2019.103455
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发表时间：
2020-02-01
影响因子：
3.9
通讯作者：
Kurtz, Steven M.
中科院分区：
文献类型：
--
作者：
Basgul, Cemile;Yu, Tony;Kurtz, Steven M.
聚芳醚酮（PEEK）因其生物相容性、射线可透性、耐久性和强度而常用于椎间融合器。虽然PEEK增材制造（AM）技术正在迅速发展，但3D打印PEEK的后处理技术仍然知之甚少。PEEK的AM具有挑战性，因为其熔融温度高（超过340摄氏度），需要专门的设备，直到最近才商业化。在ASTM实验室间研究中使用的腰椎融合器设计是在两种不同的打印速度下通过熔融长丝制造（FFF）用医用级PEEK长丝3D打印的。然后在高于PEEK玻璃化转变温度（200 ℃或300 ℃）的温度下对PEEK融合器进行退火。对AM笼进行CT扫描，以确定退火前后的孔隙率。根据ASTM F2077（ASTM F2077，2014）对融合器进行力学试验。SEM图像有助于评估热处理前后融合器的表面形态。观察到退火在任一温度下均未产生明显更好的机械性能，然而，在所有负载条件下，在较低打印速度下，退火对保持架的机械性能有影响。虽然退火后孔的结构发生了变化，但作为后处理方法，本文研究的退火条件不能减少3D打印过程中形成的不期望的孔隙率，也不能改变失效机制，这是由于层间脱粘。
Polyaryletheretherketone (PEEK) has been commonly used for interbody fusion devices because of its biocompatibility, radiolucency, durability, and strength. Although the technology of PEEK Additive Manufacturing (AM) is rapidly developing, post-processing techniques of 3D printed PEEK remain poorly understood. AM of PEEK has been challenging because of its high melt temperature (over 340 degrees C) and requires specialized equipment which was not commercially available until recently. A lumbar fusion cage design, used in ASTM interlabora tory studies, was 3D printed with a medical grade PEEK filament via Fused Filament Fabrication (FFF) under two different print speeds. PEEK cages were then annealed above the PEEK's glass transition temperature, at 200 degrees C or 300 degrees C. AM cages were CT scanned to determine the porosity before and after annealing. Mechanical tests were conducted on cages according to ASTM F2077 (ASTM F2077, 2014). SEM images helped to evaluate the cages' surface morphology before and after heat treatment. It was observed that annealing did not produce markedly better mechanical properties at either temperature, however, it had an effect on the cages' mechanical properties at lower printing speed under all loading conditions. Although the structure of the pores changed after annealing, annealing conditions examined here as a post-processing method were not able to decrease the undesired porosity formed during the 3D printing process or change the failure mechanism, which is due interlayer debonding.