Overview
Continuous carbon fiber reinforced thermoplastic composites (CFRTPs) offer excellent mechanical performance for aerospace, automotive, and structural applications. However, 3D printing such materials with high fiber alignment and density remains a major challenge—especially in complex geometries.
Our team at the University of Manchester (UoM) presents a new toolpath generation method that significantly improves fiber alignment and placement density in multi-axis 3D printing of CFRTPs.
The Problem
Conventional fiber toolpaths often suffer from:
- Direction inconsistency: Stress-based paths are hard to align due to vector ambiguity.
- Sparse fiber coverage: Limited fiber density reduces reinforcement effects.
- Poor handling of complex regions: Around holes or curved surfaces, paths break or misalign.
These issues limit mechanical performance and print reliability.
In the blade structure under stress, the traditional method showed inconsistent fiber alignment and irregular spacing. Our method generated a smooth, dense, and stress-aligned fiber layout: (a, b) Principal stress field under loading; (c) Projection onto the curved surface, showing turbulence; (d) Smoothed direction field using 2-RoSy; (e) Periodic strip pattern with uniform spacing; (f1) Extracted fiber path from our method, compared to (f2) from baseline; (g) Final manufacturing path after constraint-based post-processing.
Our Solution
We developed a stress-guided, high-density toolpath algorithm with three key features:
- 2-RoSy Direction Field: Removes directional ambiguity, ensuring smooth, consistent fiber alignment along principal stresses.
- Periodic Scalar Field: Generates evenly spaced fiber paths for dense and uniform coverage.
- Hole and Geometry Compatibility: Supports complex structures by maintaining layer continuity and enabling fiber wrapping around holes.
Source Code is available!
Results
We validated our method on various printed structures using an 8-DoF robotic 3D printer:
- Fiber coverage: Up to 87.5%, compared to 26% in previous methods.
- Tensile strength: Increased by 84.6%.
- Stiffness: Improved by 54.4%.
- Bending load capacity: Boosted by 140.8%.
Microscopy confirmed denser fiber layout and better bonding. All parts were printed with smooth, manufacturable toolpaths.
Applications & Outlook
This method enables more efficient and reliable 3D printing of CFRTPs—especially for parts with curved layers, holes, and stress-sensitive zones. It’s ready for use in aerospace brackets, structural joints, and lightweight load-bearing designs.
Further improvements will focus on real-time sensing and adaptive path control to push fiber performance even further.
Contact:
Tianyu Zhang (zhangty019@gmail.com)