Simulating CNT Alignment in SLA 3D Prints

Stereolithography (SLA) 3D printing has had rather limited use of carbon nanotubes (CNTs) as additives with its historic use for making parts ESD safe. However, it has been demonstrated that CNTs in resin parts increases part strength and aligning the nanotubes within the part increase strength even further. This project aims to compare the effects of aligning CNTs in static viscosity resin to that of dynamic viscosity of curing resin and the determine the feasibility of CNT alignment in SLA 3D printing. Through simulation it can be shown that supposed sweet spot for CNT alignment on a viscosity profile exists however, the gains in time and alignment quality are marginal at best.

The simulation models the alignment of carbon nanotubes in two dimensions within a resin matrix under the influence of an electric field. Key focus areas include:

- Dielectrophoretic (DEP) torque from electric fields - Viscous friction effects - Coulombic interactions between charged nanotubes

The simulation incorporates time-dependent viscosity changes during resin curing using the Castro-Macosko model, which accounts for the degree of cure evolving from 0 to 1.