The strength and stiffness of parts made by Fused Filament Fabrication (FFF) are highly dependent on printing parameters, and particularly so for Z-direction and interlaminar/inter-trace properties. The strength and stiffness are somewhat affected for parts made from semi-crystalline polymer, and strongly affected for parts made from chopped carbon or glass fiber reinforced polymer.
Various forms of Thermoplastic-Liquid Crystal-Polymer (TLCP) filament have been studied in the research literature and have recently become available in the 3D printing market. One form of these new TLCP based filaments involves continuous TLCP fibrils reinforcing a thermoplastic matrix polymer. These new high performance filament materials have been used to 3D print FFF parts with strengths upwards of 200MPa and modulus upwards of 20GPa using open system desktop 3D printers. The strength and stiffness of parts printed from TLCP based filament have been shown to vary by up to 10x with simple modification of acceptable printer parameters. These tailorable properties with exceptional upper limits and are enabled by the introduction and control of molecular orientation during 3D printing.
This presentation will share the results of a study examining how printing parameters in FFF affect the decree of molecular orientation, and thus mechanical properties in a new class of commercially available TLCP materials. Intra-trace (along the trace direction) properties will be contrasted with inter-trace/inter-laminar properties, as both are affected by printing parameter induced control of molecular orientation of rigid rod TLCP polymers. These new materials with exceptional and tailorable properties can be used with distributed compliant design for innovative applications such as morphing wings, various aerostructures in unmanned drones as well as offering stronger parts and shorter print times for jigs, fixtures and other structural parts.
Learning Objectives:
List important materials and printing parameters that enable high-strength and high-stiffness parts in fused filament fabrication.
Recognize how new TLCP polymer materials enable high-strength and high-stiffness parts to be printed with low-cost desktop printers as well as larger industrial systems.
Understand the materials science mechanisms responsible for the exceptional and tailorable mechanical properties.
