Influence of 3D Printing Infill Patterns on the Effective Thermal Properties

Abstract

The interior of most 3D printed objects is not completely solid, but rather a partially hollow infi ll pattern is used to save material and manufacturing time. Most commonly used infi ll designs were optimized for the mechanical strength-to-weight ratio, but little research exists on the effect of the 3D printed infi ll pattern on the thermal conductivity. As 3D printing penetrates into all types of industries and research areas, thermal properties become increasingly important. This project focuses on characterizing the effective thermal conductivity of 3D printed parts with different infi ll patterns. Specifi cally, three major commercially used infi lled patterns (zig-zag, linear crossing, and hexagon) are investigated experimentally and through numerical simulations. The thermal conductivity of 3D printed parts is not expected to be isotropic, and the orientation of the 3D printing fi laments impacts the heat conduction anisotropy. Thermal models are fi rst used to study the impact of infi ll pattern parameters on thermal conductivity, k. Neglecting natural convection, the models predict that thermal conductivity depends nearly linearly on the volume infi ll percentage, but the pattern orientation also impacts heat transfer. For the zig-zag infi ll patterns, as the infi ll supports are rotated, the highest k occurs when the supports are aligned with the direction of heat fl ow, and the lowest k occurs when the supports are perpendicular to the heat fl ow direction.