# Parts on Demand

/ Published April 20, 2016
Fort Belvoir, Virginia, 
Hershey’s uses 3D printing to make chocolate kisses. A Minnesota man built a concrete castle using 3D printing, and prosthetics companies are using it to build custom arms and legs. Now, Defense Logistics Agency officials are looking into whether 3D printing could help lower the cost of some military repair parts and fill in gaps where material and manufacturing are sparse.

3D printing, also known as additive manufacturing, could change the way DLA provides parts in the future, said Kelly Morris, chief of research and development for DLA Logistics Operations.

“Imagine if we had an additive manufacturing machine and everything that goes with it at the Air Force’s logistics center in Oklahoma. We could send them the 3D technical data package for a particular part, and they could make it right there on site,” she said.

This emerging technology could dramatically reduce the time it takes customers to get parts and in most cases minimize or eliminate the need for transportation and storage fees, Morris added.

The possibilities are years away, but DLA’s research and development team is already working with the military services to identify 10 parts for possible 3D modeling and manufacturing. Items were selected based on such criteria as backorder status, how long they take to produce, whether manufacturers have the machines and skills to produce them, and whether material to create them by additive manufacturing is available.

The top two candidates have been described by the Naval Air Systems Command as critical and hard to source. The first is a leading-edge extension for the AV-8B Harrier II jet, designed to improve airflow at high angles of attack and low airspeeds. The second is a ball fitting that mounts the engine exhaust duct to the airframe of the CH-53E Sea Stallion helicopter. 

Unlike traditional methods of manufacturing that follow a subtractive process and require machines like drills and mills to cut and shape material, additive manufacturing uses a laser-powered 3D printer to lay down successive layers of material, such as plastic or metal, to create functional parts and products.

“If you’re forging something, you’re taking a piece of metal and heating it up, then hammering or smashing it into the design you want. There’s almost always excess material that needs to be trimmed away,” Morris said, adding that additive manufacturing leaves much less waste although some machining or milling may be needed to complete the product.

The process starts with a 3D technical data package, or digital blueprint, that depicts all of an item’s specifications. For the initial parts DLA intends to have additively manufactured, the agency will do a limited test of contractors’ additive manufacturing capabilities. Those contractors will use 3D data specifically approved for additive manufacturing and produce parts for testing.

After the parts are produced, DLA will work with the military services’ engineering support activities to evaluate feasibility of testing, evaluation and acceptance of parts, also known as first-article testing, into the supply system.

The introduction of 3D parts into DLA’s inventory will require additional focus on data integrity as the agency meets the challenges of storing and accessing 3D drawings, added Tony Delgado, DLA’s 3D program manager.

“There’s a cyber security component here. When data is transferred between manufacturers and DLA, we need to ensure it’s done in a secure environment so there’s no interference and no one is changing the specifications,” he said.

That will also lead to the need for training quality assurance specialists to certify that manufacturers are producing 3D parts that comply with technical requirements. While the military’s engineering support activities are responsible for testing and certifying that additively manufactured parts meet structural standards, DLA maintains the role of quality assurance.

“Even industry is struggling with training and certification. Pennsylvania State University and the University of North Carolina have academic programs specifically for additive manufacturing, so they are developing the workforce curriculum for that,” Delgado said. “DLA might have to bring those skills into the quality assurance arena so we understand the designs and material qualifications when inspecting vendors.”

Defense Department officials have become more interested in additive manufacturing as the department works to increase innovation and embrace new technologies. DLA is helping to shape DoD’s additive manufacturing program by creating a repeatable process to identify suitable parts for additive manufacturing.

And just because a part can be produced additively and meet military standards doesn’t mean DLA or the military services should forgo traditional manufacturing, Morris said. Evaluation factors will include the cost of generating 3D data, additive manufacturing costs, demand patterns and whether a part made additively has the same lifecycle as one produced with traditional methods, she added.