Field-Based Toolpath Generation for 3D Printing Continuous Fibre Reinforced Thermoplastic Composites

TL;DR

This paper introduces a novel field-based method for generating toolpaths in 3D printing of continuous fibre reinforced thermoplastic composites, optimizing fibre placement based on stress analysis to improve mechanical strength.

Contribution

The method uniquely uses stress tensor analysis to adaptively generate toolpaths, enhancing fibre reinforcement efficiency and mechanical performance in 3D printed composites.

Findings

Up to 71.4% increase in mechanical strength with the new method.

Adaptive toolpath density correlates with stress distribution.

Validated on various models and physical specimens.

Abstract

We present a field-based method of toolpath generation for 3D printing continuous fibre reinforced thermoplastic composites. Our method employs the strong anisotropic material property of continuous fibres by generating toolpaths along the directions of tensile stresses in the critical regions. Moreover, the density of toolpath distribution is controlled in an adaptive way proportionally to the values of stresses. Specifically, a vector field is generated from the stress tensors under given loads and processed to have better compatibility between neighboring vectors. An optimal scalar field is computed later by making its gradients approximate the vector field. After that, isocurves of the scalar field are extracted to generate the toolpaths for continuous fibre reinforcement, which are also integrated with the boundary conformal toolpaths in user selected regions. The performance of our method has been verified on a variety of models in different loading conditions. Experimental tests are conducted on specimens by 3D printing continuous carbon fibres (CCF) in a polylactic acid (PLA) matrix. Compared to reinforcement by load-independent toolpaths, the specimens fabricated by our method show up to 71.4% improvement on the mechanical strength in physical tests when using the same (or even slightly smaller) amount of continuous fibres.