Trainer development prints in third dimension

  • Published
  • By Steve Hoffmann
  • 81st Training Wing Public Affairs
Ever wanted to print yourself? Not merely a copy of your hand, face or, if so inclined, your bottom on a sheet of paper, but a life-sized three-dimensional print of the entire you--with moving parts, too.

The 81st Training Support Squadron's trainer development flight has two printers that can print objects, 3-D objects like you. Currently, these printers primary function is to replicate things like fire extinguisher valves on C-17's in order to train students.

So, unfortunately, unless a plastic version of you adds some value to the training mission, chances are you won't be printed anytime soon. Trainer development builds trainers and these printers have proved to be a valuable asset in performing that mission.

Trainer development has had these machines for two years and it uses them in the production of parts, prototypes and replicas of real things. One recent example of its capability was in the production of a near full-scale model of a GBU-32 guided bomb unit. The model consisted of the MK-83 bomb with its joint directed attack munitions tail section and a bomb release unit. It is being used to train student pilots at Tyndall Air Force Base, Fla. on how to do pre-flight inspections on a JDAM.

According to Tom Capers, one of the fabricators at trainer development, the bomb fuselage was printed in 21-inch sections and glued together to form the bomb. Printing at two inches per hour, that can take a while.

"We had one of the printers working non-stop for hours at a time over many days," said Capers. "However, we can produce these replicas at a fraction of the time and cost it takes to build the real thing."

The process for the two printers is essentially the same -- laying down successive layers of material, one on top of the other, over and over and over, building from bottom up. However, the build process is slightly different in the two.

One printer developed by Z Corporation uses successive layers of powdered gypsum, spraying a binding agent through an ink jet printer head in just the right places. Then another layer of gypsum is spread and binding agent is sprayed. This gets repeated over and over until the object is complete. The printer has a prep station where excess powder can be vacuumed and the object can be brushed and polished. Objects made with this printer are fragile but able to achieve greater detail and can be printed in color.

The other printer developed by Stratasys Inc. uses a process known as fused deposition modeling. In this process, successive layers of molten polymer are sprayed through a printer head. Each layer is approximately one tenth of a millimeter thick and, after a few seconds of cooling time, another layer is sprayed. This gets repeated until the object is complete. Objects formed using this printer are less detailed but much more durable.

But let's get back to the printing of you. How would these printers know what to print? What frame of reference would they need? Before you or any other object can be replicated, you would need to be scanned from top to bottom using a hand held scanner that emits a diffused laser beam to record your precise measurements, recording every contour, nook and cranny. Modeling software will use these measurements to create a three-dimensional file of yourself. Any voids created in the scanning process can be corrected with this software. You might even wish to trim a little around your waist, make yourself taller, shorter -- whatever cosmetic enhancement you desire. Negative spaces or areas where moving parts are located will be identified so that a special dissolvable material can be printed and later dissolved. Then, it's pretty much a matter of hitting the print button.

Aside from its use here at Keesler, other common applications for this technology are in the areas of industrial design, architectural modeling, and dental and medical applications. Doctors and surgeons can use a 3-D printer to print a patient's specific body part in order to plan their approach before the actual procedure is performed on the patient. Even personalized body parts such as jaws, joints, hip and knees can be printed to replace a body part that might need replacing.

Envision a group of students gathered around a life-sized replica of you. You're training them on something. What is that? Is the plastic or gypsum version of you mission essential? If so, you could be just a click away.