Fabrication and Compressive Behavior of a Micro-Lattice Composite by High Resolution DLP Stereolithography

Abstract

Lattice structures are superior to stochastic foams in mechanical properties and are finding increasing applications. Their properties can be tailored in a wide range through adjusting the design and dimensions of the unit cell, changing the constituent materials as well as forming into hierarchical structures. In order to achieve more levels of hierarchy, the dimensions of the fundamental lattice have to be small enough. Although lattice size of several microns can be fabricated using the two-photon polymerization technique, sophisticated and costly equipment is required. To balance cost and performance, a low-cost high resolution micro-stereolithographic system has been developed in this work based on a commercial digital light processing (DLP) projector. Unit cell lengths as small as 100 μm have been successfully fabricated. Decreasing the unit cell size from 150 to 100 μm increased the compressive stiffness by 26%. Different pretreatments to facilitate the electroless plating of nickel on the lattice structure have been attempted. A pretreatment of dip coating in a graphene suspension is the most successful and increased the strength and stiffness by 5.3 and 3.6 times, respectively. Even a very light and incomplete nickel plating in the interior has increase the structural stiffness and strength by more than twofold.

RETRACTED: Embedded Sensors with 3D Printing Technology: Review

“…To determine the ELP deposition area for 3D electronics, Hensleigh et al used SLA printing to create a dual-material structure using positive, negative, and neutral resins, which were then soaked in positive or negative catalyst solutions [ 102 ]. Using DLP and ELP procedures to deposit metal layers on the micro-lattice, Shin et al increased the lattice’s compressive rigidity from 8.8 MPa to 11.1 MPa [ 103 ]. To fabricate high-resolution 3D conformal/embedded circuit boards, sensors, antennas, etc., Liu et al integrated laser-activated ELP with a variety of AM technologies [ 104 , 105 , 106 , 107 , 108 ].…”

The Energy Absorption Behavior of 3D-Printed Polymeric Octet-Truss Lattice Structures of Varying Strut Length and Radius

“…FDM 3D printing is particularly attractive for hobbyist applications, such as sporting equipment and art projects, due to its ease of use, low cost of both equipment and filament, and reasonable resolution [ 21 , 22 ]. Due to higher resolution, excellent surface finish quality, isotropic mechanical properties, greater material variety and faster print times, SLA 3D printing is generally preferred, and will be the focus of the current work [ 3 , 23 , 24 ].…”

“…These structures are alternatives to existing cellular materials, which include aluminum honeycombs/foams [ 20 , 25 , 26 ] and conventional expanded polystyrene foams [ 26 , 27 , 28 , 29 , 30 ]. Unlike the stochastic unit cell structure of cellular materials, the regularity of the lattice unit cell allows one to control the overall structure performance and tune/optimize the lattice geometry to create a functionally graded material for individual design applications [ 8 , 14 , 17 , 23 , 26 ]. Several different unit cell geometries exist and have been examined in the literature [ 8 , 18 , 31 , 32 ].…”

Smart Lattice Structures with Self-Sensing Functionalities via Hybrid Additive Manufacturing Technology

“…For example, Hensleigh et al employed SLA printing to fabricate the dual-material structure with positive, negative, and neutral resins and soaked it in either a positive or negative catalyst solution to define the ELP deposition area for 3D electronics [ 29 ]. Shin et al [ 30 ] used DLP and ELP techniques to deposit metal layers on the micro-lattice and the compressive stiffness of the lattice increased from 8.8 MPa to 11.1 MPa. Our group combined laser activated ELP with various AM technologies for the fabrication of high-resolution 3D conformal/embedded circuit boards, sensors, antennas, etc.…”