Additive manufacturing of functional composites is getting more attention during the past few years due to advancement in 3D printing machines as well as new materials available for printing via different AM methods such as FFF, FGF, SLS and SLA. Thermally conductive polymers require a high amount of conductive fillers to reach a certain level of conductivity needed for electrical applications such as heat sinks, enclosures, and lighting fixtures. The downside of having high loading of thermally conductive fillers in the polymer matrix (usually >30 wt.%) is the impact on rheological properties, which makes 3D printing challenging.
In the present work, a thermally conductive polymer with high thermal conductivity (>3 W/m/K) and high mechanical properties (>60 MPa of tensile strength) was first developed. Fillers were selected carefully to optimize mechanical and thermal properties at minimum filler loading. The impact of filler and flow orientation on thermal and mechanical properties was then evaluated analytically through thermal simulations of heat sinks printed in different orientations as well as experimentally through material characterization and temperature measurements of printed coupons and heat sinks. We concluded that due to the anisotropic nature of the designed thermally conductive polymer, the component’s ability to dissipate heat and withstand high loading can be improved by controlling printing direction and filler/fiber orientation, which enables this technology to be used for making industrial heat sinks and luminaire.
- Learn about thermally conductive polymers and the challenges associated with 3D printing with them.
- Understand the impact of filler/fiber orientation on thermal properties of printed conductive polymers.
- Maximize thermal performance of the printed heat sinks by changing print orientation.