Mechanical structural design based on additive manufacturing and internal reinforcement

The design of modern mechanical components often requires the use of low-density and high-strength parts. Additive manufacturing presents competence in obtaining format complexity internally (voids, ducts, channels) and externally (shape, holes). However, parts obtained by material extrusion additive manufacturing are highly anisotropic and relatively weak. This paper aims to present a new mechanical design technique that combines the high geometry flexibility of additive manufacturing with internal structuring reinforcement by high-strength materials, which enables optimized parts with reinforcement in the most mechanical stressed areas during service, through adopting structured internal geometry filled with reinforcement material. Dense test specimens and test specimens with internal structural canals filled with reinforcement material (epoxy resin and carbon fibers) were designed, fabricated and tested physically and virtually. The obtained results provide property values for 3D-printed acrylonitrile butadiene styrene (typical material of additive manufacturing) and for this polymer reinforced with various reinforcement material configurations (useful for mechanical design). The reinforcement decreased anisotropy and improved mechanical properties. Optimized parts filled with resin and long carbon fibers had maximum flexural resistance of 112 MPa, with a specific weight of 1.1 g/cm(3). This reinforcement provided parts with specific flexural strength similar to structural aluminum alloys, preserving the geometry and external dimension of the printed parts. The technique presented here shows the possibility of new conceptions in mechanical components design and strength optimization by internal reinforcement canals in parts. The technique is useful for mechanical design activity and allows for new product conceptions based on additive manufacturing.