Manufacturing of Mono-Material Tunable Thermal Expansion Structures using Additive Extrusion

Abstract

Currently, structures of tunable or even negative thermal expansion usually consist of two materials with different thermo-mechanical behaviour. Manufacturing of such structures therefore requires the ability to process two materials simultaneously or in short sequence. This paper contributes towards the simplification of said manufacturing process: It presents an approach that allows to design tunable thermal expansion structures using only exactly one single material. In principle, it describes a lattice structure that is activated by the thermomechanically orthotropic behavior of additively extruded beads. Tuning thermal expansion properties is thus possible by adapting the geometry of the structure itself or its processing parameters. The latter is presented briefly in a parameter study, using the example of layer height and printing speed. Future applications can range from the compensation of processinduced distortions to thermally triggered actuators.