Geometric Perforation for Controlling Elasticity in 3D Printing
Shane Transue, PhD student & Min Choi, CMTC Co-Director

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Summary:
This research explores how Computer Aided Design (CAD) applications can be used to procedurally generate geometric structures that control the elastic behavior of 3D printed objects. Our work provides a set of applications and algorithms that allows users to create hollow structures that modify how 3D printed materials behave once they have been printed. The objective of this research is to provide control of elastic behaviors for 3D objects without the extreme cost of 3D multi-material and voxel printers.

Problem that Inspired Research:
3D printing has established a solid foundation for replicating the shape of hard objects and has recently expanded into adding textures, color, and other material properties. However, the introduction of elastic 3D printable materials is still quite limited and is only customizable using extremely expensive 3D printers (>$10K USD).  The options for controlling elastic behavior for consumer-level 3D printers is quite limited. Even for printers that have a discrete number of elastic materials (ex. 1=soft, 10=hard), there is no way to mix arbitrary levels of elastic materials to get exact control (ex. 5.5/10) of the printed material. This means that there is no current way to precisely control elastic material behaviors of 3D prints using consumer-level 3D printers. Even as newer printers provide more options for flexible materials, obtaining exact behaviors from a 3D print will still be difficult. Additionally, even if the user is free to mix a set of elastic materials, obtaining the exact mixture for the desired outcome remains a difficult process.

Objective / Proposed Solution:
The aim of this research is to provide a simple and open-source set of algorithms that can be simply downloaded and used with any 3D printer. This method allows control of the geometric structure of 3D printed objects to change how they deform using only one type of flexible ink, as is provided by most consumer-level 3D printers. Through expanding the possibilities of 3D printing complex materials, this will have a significant influence on 3D printing research which has already established widespread impact on research in mechanical engineering, material science, and industrial design.

Greatest Challenge to Overcome:
The domain of 3D printing is an extremely popular and ever changing research area, so the core technologies, algorithms, and hardware is constantly in flux. Therefore, contributions within this domain must provide flexible solutions to difficult problems that can adapt to this ever changing environment. This means that any contribution must be usable with a large variety of 3D printers and existing software. To handle every case, there has been a significant challenge in providing a theoretical basis for generating correct geometry for any provided input mesh. Another challenge is related to deployment, the resulting algorithm should be simple to use and easy to obtain and use with any existing 3D printer.

Benefits of Research:
One of the primary contributions of this research is the open-source code of the core algorithm that allows the geometric perforation method to be used by anyone with their own 3D printer or within any application. This is an extremely useful tool for mechanical engineers and industrial designers due to the ability to prototype and refine elastic materials.

Real-World Application(s):
The application of this research fits within the academic domain and industry through the development of new complex geometric structures that can alter how objects behave in dynamic situations. For example, there are numerous potential applications in: soft robotics, elastic material prototyping, component manufacturing, and interactive objects for Virtual and Augmented Reality (VR/AR).

Innovations to Media and Technology:
Due to the broad applicability of 3D printed objects, this research contributes significantly to this domain at a fundamental level. This is due to the core method being applicable to any 3D printed object. Within media and technology this may incorporate the use of controlling elastic components in robotics, introducing real-world interactive objects for Virtual and Augmented Reality (VR/AR), and other forms of game entertainment.

Cutting-edge Technology Being Used:
The objective of this research is to work around the most expensive cutting edge technologies. However, in the direction of providing more flexibility in how consumer-level printers can be used, this research looks at how current 3D multi-material printers operate and how the same level of flexibility can be introduced to a wider user-base.

Transdisciplinary Collaboration:
This research incorporates components from computer simulation, mechanical engineering, materials science, and the evolving field of 3D printing. The process of design, prototyping, 3D printing, and behavior optimization incorporates fundamental contributions from all of these fields.

Additional Information:
This research is interdisciplinary project between Computer Science (Dr. Min-Hyung Choi), Mechanical Engineering (Dr. Kai Yu), and Inworks at both the UC Denver and Anschutz Medical Campuses. This research is partially funded by the DoEd GAANN Fellowship: P200A150283.