Toward the Printed World: Additive Manufacturing and Implications for National Security

Abstract

Additive manufacturing (AM)--commonly referred to as "three-dimensional" or "3D" printing--is a prospective game changer with implications and opportunities that affect not just the Department of Defense (DOD) but the economy as a whole. The technology allows the "art to part" fabrication of complex objects from a computer model without part-specific tooling or human intervention. (1) AM has already impacted a variety of industries and has the potential to present legal and economic issues with its strong economic and health-care benefits. Because of its remarkable ability to produce a wide variety of objects, AM also can have significant national security implications. The purpose of this paper is to provide a general introduction to these issues for nontechnical readers through a survey of the recent history and the current state of technology. Included in this paper is a brief review identifying key individuals and organizations shaping developments as well as projected trends. AM refers to the production of a three-dimensional object through the layer-by-layer addition of material according to a geometrical computer model. AM contrasts with other forms of manufacturing that require either the removal or alteration of material to produce a completed object. For example, a 3D printer could build a crescent wrench by adding a layer of material and stacking another layer on top of that one and fusing them together, repeating the process until the wrench is complete. There are distinct benefits to objects produced in this manner. Considering the above example, if a customer wanted a wrench to be fashioned with a grip unique to his hand, he could scan his hand by computer and modify the existing design accordingly before the 3D printer begins production. Additionally, since the wrench is not assembled from preexisting parts, it would be a complete entity--unable to break into component parts as there is only one "part." Since the wrench is made by additive manufacturing as opposed to conventional "subtractive manufacturing"--taking a block of raw material and removing excess until the finished product remains--the process as a whole is more efficient and less wasteful. [ILLUSTRATION OMITTED] Another major benefit of AM is the fact that complexity is "free." In conventional manufacturing, increasing design complexity entails increased costs. AM allows for complexity to increase independently of cost. By AM's very nature of layer-by-layer additions, one can optimize in advance via 3D software a given engineering component's strength, durability, and other material properties. For example, in the aerospace industry, one typically desires high strength but low weight. Weight savings translate into savings on fuel consumption. Traditional subtractive manufacturing is fundamentally limited in its ability to remove material from the interiors of aerospace components to optimize these conflicting parameters. With AM, however, one can design a part to have more material where strength is needed, and less where it is not. Moreover, the changing of a digital design and reprinting of it via AM are more cost-effective than retooling subtractive systems and remanufacturing the same part. Developed in the late 1980s, 3D printers are becoming more affordable and dynamic, able to handle a greater variety of material than before. Researchers at Wake Forest University have used AM to produce a range of living tissue, including human skin. This potential has not gone unnoticed by the defense community--the Armed Forces Institute of Regenerative Medicine (AFIRM) has funded such initiatives and fostered collaboration between research institutions. Commerce and industry have also been shaped by these developments. The relative ubiquity of 3D printers, combined with the increasing range of materials these devices can handle, has fostered the growth of a new industry around manufacturing specialized components. …