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

• Published in: Additive manufacturing 2022-01, Vol.49, p.102470, Article 102470
• Main Authors: Chen, Xiangjia, Fang, Guoxin, Liao, Wei-Hsin, Wang, Charlie C.L.
• Format: Article
• Language: English
• Subjects: Continuous Fibre Reinforcement; Stress-Field; Thermoplastic Composites; Toolpath Generation
• ISSN: 2214-8604; 2214-7810
• DOI: 10.1016/j.addma.2021.102470

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. [Display omitted] •A method to convert the stress-field obtained from FEA into a scalar-field to generate toolpaths for 3D printing CFRTPCs.•An algorithm to extract adaptive CCF toolpaths by controlling the minimally allowed distance between neighboring toolpaths.•A method to merge the boundary conformal toolpaths in user-specified boundary regions to reinforce the contact interface.•Physical experiment on a variety of models in different loading conditions to verify the advantage of our approach.