Abstract

Additive manufacturing (AM) of medical devices including orthopaedic implants and hearing aids is highly attractive because of AM’s potential to match the complex form and mechanics of individual human bodies. Wearable and implantable tissue-support devices, such as ankle or knee braces, and hernia repair mesh, offer a new opportunity for AM to mimic tissue-like mechanics and improve patient quality of life. Here, we demonstrate how explicit programming of the toolpath in an extrusion AM process can enable new, flexible mesh materials with digitally tailored mechanical properties and geometry. Meshes are fabricated by extrusion of thermoplastics, optionally with continuous fibre reinforcement, using a continuous toolpath that tailors the elasticity of unit cells of the mesh by incorporation of slack and modulation of filament-filament bonding. We show how the tensile mesh mechanics can be engineered to match the nonlinear response of muscle, incorporate printed mesh into an ankle brace with directionally specific stiffness, and present further concepts for tailoring the 3D geometry for medical applications.