Commandant of the Marine Corps Gen. Robert Neller published an interim policy on additive manufacturing in the Marine Corps. In it, he imposes safety protocols for specific situations, such as requiring that a printed part to be used on a configuration controlled system be rendered in a bright color to distinguish it from the original equipment it is used with.

However, the directive is also a call for all Marines to explore the potential benefits of 3-D printing. As a result, Marine Wing Support Squadron 372 is experimenting with 3-D printing parts that eventually might be included on military vehicles.

The Marines learned how to use the printer through trial and error. Image source: U.S. Marine Corps)Capt. Marc Blair, a combat engineer officer with the squadron, led the project after he attended a presentation on additive manufacturing. His unit includes 72 occupational fields, all of which would likely find some use for 3-D printing.

The Invent3D printer used by the unit uses a single extrusion head and spool of black plastic tubing that feeds into the printer head. From there it is heated to about 220 degrees Celsius, making it pliable enough to print the desired object.

They measured a Humvee door handle by hand, and Chief Warrant Officer 2 Mathew Wright, a motor transportation maintenance officer, entered the data into the Tinkercad program. He chose to use a honeycomb pattern to fill the inside of the handle. That virtual model then was transferred to a second program, which translates the virtual model into the specific commands that tell the printer what to print.

This two-step process means that one virtual model master file can be translated into the specific language to any make and model of printer that is being used. Instead of Marines having to write different files for each type of printer they might use, the Marine Corps could have one standard file used across the Corps, and translate it into commands according to whatever printer is on hand.

If one unit develops and tests a successful part on their printer, that design can be sent to other units to begin using with their printers. The MWSS-372 Marines also hope that if they can prove the utility of 3-D printing in the field, they will be able to get a printer with the ability to make objects out of materials such as metal or rubber.