Session: 03-16-01: Manufacturing: General

Paper Number: 112988

112988 - Parametric Modeling of Lattice Structures for Manufacturing via Masked Stereolithography Apparatus 

Lattice structures provide many desirable characteristics when compared to a bulk material of similar size. Through removal of unnecessary material and subsequent lightening, lattice structures can be applied in many applications where weight saving is critical such as in the aerospace industry. Lattice structures offer more surface area, leading to better heat dissipation properties. Varying lattice parameters throughout an object allows engineers to fine-tune the structure to suit the desired application such as increasing or decreasing the strength in a specific area. Lattice structures can be combined with other objects through simple boolean operations (union, subtract, intersect) to create largely hollow complex internal structures that supply comparable integrity and support at a fraction of the weight of a solid object. Manufacturing of complex lattice structures via additive manufacturing allows for the creation of geometry that could otherwise be impossible when considering traditional manufacturing techniques. Due to the nature of the geometry of lattice structures, designing a mold is impossible in all but the most trivial of cases meaning lattice structures cannot easily be injection molded or cast, if at all. Similarly, the geometry of lattice structures do not lend themselves well to subtractive manufacturing, where reaching the internal sections of the lattice would be difficult.

An investigation into parametric modeling of lattice structures is conducted in pursuit of an effective and efficient process for manufacturing lattice structures via masked stereolithography apparatus (MSLA). Principals of Design for Additive Manufacturing (DfAM) are applied, keeping in mind the manufacturing process to be used. Key design features are parameterized to decrease the effort required to design and implement changes to the structures. Unit cells are modeled as interconnected struts according to parameters such as unit cell side length, strut diameter or thickness, and unit cell solid volume fraction. As well as parameterizing the unit cell geometry, the number of cells in each of the three cartesian directions are parameterized such that a three dimensional array of unit cells is constructed based on the single unit cell. In the case that a lattice is to be used as the internal structure for another object, the object’s “skin thickness” is also parameterized. Three unit cells are to be considered: the simple cubic unit cell, the body-centered cubic (BCC) unit cell, and the face-centered cubic (FCC) unit cell. A simple procedure for interfacing the lattice to bulk material is proposed. The proposed design process is validated through qualitative analysis of lattice samples designed with varying unit cell and overall lattice properties such that the modeling technique may be assessed for efficacy and ease of use. Additionally, an example of replacing a solid model’s interior with the lattice structure is detailed to demonstrate the simplicity and power of the approach.

Presenting Author: Yingtao Liu University of Oklahoma

Presenting Author Biography: Dr. Yingtao Liu is an Associate Professor in the School of Aerospace and Mechanical Engineering at the University of Oklahoma.

Authors:

Benjamin Sherwood The University of Oklahoma
Christopher Billings The University of Oklahoma
Yingtao Liu University of Oklahoma