Supportless Lattice Structure for Additive Manufacturing of Functional Products and the Evaluation of Its Mechanical Property at Variable Strain Rates

Abstract

This study proposes an innovative design solution based on the design for additive manufacturing (DfAM) and post-process for manufacturing industrial-grade products by reducing additive manufacturing (AM) time and improving production agility. The design of the supportless open cell Sea Urchin lattice structure is analyzed using DfAM for material extrusion (MEX) process to print support free in any direction. The open cell is converted into a global closed cell to entrap secondary foam material. The lattice structure is 3D printed with Polyethylene terephthalate glycol (PETG) material and is filled with foam using the Hybrid MEX process. Foam-filling improves the lattice structure’s energy absorption and crash force efficiency when tested at different strain rates. An industrial case study demonstrates the importance and application of this lightweight and tough design to meet the challenging current and future mass customization market. A consumer-based industrial scenario is chosen wherein an innovative 3D-printed universal puck accommodates different shapes of products across the supply line. The pucks are prone to collisions on the supply line, generating shock loads and hazardous noise. The results show that support-free global closed-cell lattice structures filled with foam improve energy absorption at a high strain rate and enhance the functional requirement of noise reduction during the collision.

Improving the Mechanical Properties of a Lattice Structure Composed of Struts with a Tri-Directional Elliptical Cylindrical Section via Selective Laser Melting

“…For a tri-directional elliptical cylindrical section (TEC) and a cylindrical section (RD) of equal area, the area moments of inertia for the x-axis are I xTEC and I xRD , respectively. I xTEC > I xRD (5) This indicates that the TEC has a better ability to resist bending. Normal stress can be calculated from…”

“…Additive manufacturing largely bridges the gap between innovative design and advanced manufacturing [1][2][3][4][5]. As a typical example of an advanced structure, additive manufacturing lattice structures are becoming increasingly important in promoting the development of lightweight, multifunctional, intelligent, and biomimetic materials and structures.…”

Design and characterization of 3D-printed TPU-based lattice structures. Application to methodology for the design of personalized therapeutic products

“…Overhang is related to the maximum angle up to which a 3D parts can be 3D printed support free with, where a maximum overhang angle of 45° is considered a safe approximation. Moreover, the bridging distance depends on the melt viscosity of the extruded material and its cooling rate (Prajapati et al , 2022a). Both features can be optimized by adjusting variables such as printing speed, printing temperature and cooling speed among others.…”

“…In this sense, conventional manufacturing methods currently do not rival FFF processes because it is possible to generate free-support non-solid internal geometries with the possibility of providing a different elasticity to the same product, as well as obtaining elastic materials from rigid materials and different elasticities from the same elastic material (Herzberger et al , 2019; Rahmatabadi et al , 2023b; Rodríguez-Parada et al , 2021). As a consequence, the versatility and control over the manufacturing process offered by AM, has led to a growing trend in the use of lattice structures, making available a wide range of possibilities in the manufacture of lattice geometries and structures with more complex architectures (Almesmari et al , 2023; Günaydın et al , 2022; Kumar et al , 2020; de la Rosa et al , 2023; Nazir et al , 2023; Niknam and Akbarzadeh, 2020a; Prajapati et al , 2022a; de la Rosa et al , 2021). Several geometric lattice structures have been tested to improve their performance as a function of their mechanical properties (Almesmari et al , 2023; Günaydın et al , 2022; Mahbod and Asgari, 2019; Momeni et al , 2019; Nazir et al , 2023; Niknam and Akbarzadeh, 2020; Pham et al , 2019; Prajapati et al , 2022a; Sha et al , 2018; Wang et al , 2022).…”

“…As a consequence, the versatility and control over the manufacturing process offered by AM, has led to a growing trend in the use of lattice structures, making available a wide range of possibilities in the manufacture of lattice geometries and structures with more complex architectures (Almesmari et al , 2023; Günaydın et al , 2022; Kumar et al , 2020; de la Rosa et al , 2023; Nazir et al , 2023; Niknam and Akbarzadeh, 2020a; Prajapati et al , 2022a; de la Rosa et al , 2021). Several geometric lattice structures have been tested to improve their performance as a function of their mechanical properties (Almesmari et al , 2023; Günaydın et al , 2022; Mahbod and Asgari, 2019; Momeni et al , 2019; Nazir et al , 2023; Niknam and Akbarzadeh, 2020; Pham et al , 2019; Prajapati et al , 2022a; Sha et al , 2018; Wang et al , 2022). It was found that geometric and manufacturing variables, as well as the elastic variant, play a critical role in the variation of stiffness, deformation mechanisms and energy absorption properties (Bates et al , 2019; Dar et al , 2020; Habib et al , 2019; de la Rosa et al , 2021; Tafazoli and Nouri, 2022), even an adequate hybridization of several structures can lead to reducing the universal anisotropy (Khaleghi et al , 2021).…”