Thermoplastic Extrusion Additive Manufacturing of High-Performance Carbon Fiber PEEK Lattices

Abstract

Polyetheretherketone (PEEK) has been the focus of substantial additive manufacturing research for two principal reasons: (a) the mechanical performance approaches that of aluminum at relatively high temperatures for thermoplastics and (b) the potential for qualification in both the aerospace and biomedical industries. Although PEEK provides outstanding strength and thermal stability, printing can be difficult due to the high melting point. Recently, high-temperature soluble support has enabled the printing of lattices and stochastic foams with overhanging features in these high-performance carbon fiber thermoplastics, in which density can be optimized to strike a balance between weight and strength to enhance performance in applications such as custom implants or aerospace structures. Although polymer powder bed fusion has long been capable of the combination of these geometries and materials, material extrusion with high-temperature sacrificial support is dramatically less expensive. This research provides a comprehensive mechanical analysis and CT-scan-based dimensional study of carbon fiber PEEK lattice structures enabled with high-temperature support and including model validation.

Experimental and Numerical Investigation of a Lattice Structure for Energy Absorption: Application to the Design of an Automotive Crash Absorber

“…In conclusion, many works [14][15][16][17][18][19][20][21][22][23] have shown that lattice structure can be opportunely designed and manufactured through the AM technique to obtain unprecedented properties in the energy absorption. The reader can refer to Tamburrino et al [24] for a recent extensive literature review on the design process of additively manufactured lattice structures.…”

“…In particular, unit cell types, sizes, densities, and structures were taken into consideration. Even though many works in the literature [14][15][16][17][18][19][20][21][22][23] have addressed the mechanical behavior of lattice structures made with thermoplastic polymers, reinforced and not, a comprehensive study that experimentally analyzes the mechanical behavior of lattice structures and applies these results for the design of a component subjected to crash has not been reported and was the aim of this work.…”

“…More recently, Santiago et al [ 18 ] used lattice structures made in PEEK materials for high temperature applications such as custom implants or aerospace structures. Although the study points to high temperature applications, it reports a preliminary activity on a small lattice structure made of amorphous PEEK, semi-crystalline PEEK, carbon fiber PEEK, and PEEK lattices based on an octet configuration.…”

Low Impact Velocity Modeling of 3D Printed Spatially Graded Elastomeric Lattices

“…Surface-based geometries and triply periodic minimal surface (TPMS) configurations as a spherical shell, gyroid, IWP, OCTO, Schwarz, TPMS diamond, and TPMS primitive have also been studied [ 5 , 7 , 14 , 15 , 29 , 30 , 31 , 32 ]. Likewise, modifications and combinations of the basic truss-based geometries can also be found in the literature, such as the re-entrant dodecahedron, reinforced BCC, octet, and face-body-centered cubic (FBCC), as well as structures with varying distribution of the volume fraction of each unit cell in the 3D design domain, also known as spatially graded lattices [ 5 , 7 , 9 , 18 , 22 , 24 , 25 , 26 , 27 , 33 , 34 , 35 , 36 , 37 , 38 , 39 , 40 ]. The manufacturability of some of the aforementioned geometries could be limited by the post-processing method, such as heat treatment, curing, or cleaning [ 10 ].…”

“…Lattice structures are mainly evaluated by their stiffness and energy absorption capabilities through quasi-static compression tests [ 9 , 10 , 11 , 12 , 13 , 14 , 16 , 17 , 19 , 22 , 27 , 30 , 34 , 35 , 36 , 37 , 38 , 39 , 41 ] and dynamic compression tests [ 18 , 22 , 23 , 25 , 35 , 42 ]. The behavior of the lattices is mainly affected by the geometry of its unit cell, the relative density, and the properties of the parent material [ 4 , 28 , 43 , 44 ]; therefore, multiple tests are carried out on the base (solid) material to characterize its mechanical behavior under tensile, flexural, and compressive loads [ 8 , 11 , 13 , 14 , 19 , 27 , 29 , 31 , 34 , 35 , 36 , 38 , 39 , 42 , 45 , 46 ], commonly via universal testing machines (UTM). The mechanical characterization of the base material and the appropriate adjustment to a material model enables the improvement of the design process and the study of lattice structures.…”