3-D printing saves maintainers money at Hill

Published Dec. 12, 2014
By Bill Orndorff
Ogden Air Logistics Complex

HILL AIR FORCE BASE, Utah -- The 309th Maintenance Support Group has a long history of building items, ranging from wooden office doors to splash molds that detect aircraft cracks. New technology is adding Rapid Prototyping, often referred to as 3-D printing, to the mix.

Part of the group's Engineering Division and located in the group's Precision Measurement Equipment Laboratory Facility, the equipment includes two printers -- one that makes items from powder and another that uses coiled plastic.

The newest machine, a Fortus 900mc, has been in place for two months and uses thermoplastic to create the item. According to company information, some of the materials can hold up in high heat, and against caustic chemicals, sterilization and high impact.

"Printing a part begins with a customer sending a Computer Aided Design -- CAD -- file. The printing software uses an slt (stereolithography) format, but we can convert other formats to slt. We can also develop the CAD model if needed," said Taylor Gittins, 309th MXSG manufacturing engineer.

"Depending on how large and complex the item is, it can take anywhere from 30 minutes to a day to produce the item," Gittins said. "The machine can safely run overnight without anyone watching it."

Roughly the size of a seven-passenger minivan, the Fortus 900 reproduces the item a layer at a time by applying the pliable plastic. The thermoplastic materials used by the Fortus system can create durable parts, according to company information.

One of the materials, called ULTEM 9085, is resistant to smoke and toxicity and has a high strength-to-weight ratio. In order to satisfy the requirements of a variety of workloads, MXSG has purchased four different material options to use with the printer, varying in strength and other properties.

The printer can produce items up to 3 feet by 2 feet by 3 feet in size, though larger items can be reproduced in pieces and fused together later. And if a customer has an item with no technical data, the MXSG measurement laboratory can accurately measure it so a CAD file can be developed for printing or manufacture, Gittins said.

"We work with the customers to determine what their needs are," Gittins said. "So far, we've received positive feedback from customers, as we have been able to quickly make design changes to meet their specifications."

One customer, David Astle, a chemical engineer with the 532nd Commodities Maintenance Squadron, considers the printer to be an asset to his area.

"I love that printer," Astle said. "It has allowed me to rapidly create parts we use in our processes, in a timely manner and with precision. It has been a great asset to what we've accomplished here."

Astle, who uses the parts for landing gear processing procedures, said he was pleased with how the printer "gets it right the first time."

"Money and time cost savings are enormous," Astle said. "Several of our departments place ongoing orders through MXSG. We can send them a patch and the part is ready the next day."

Printing an item costs about $5 to $8 per cubic inch but can be a substantial savings over building a prototype from metal. One item the group printed originally cost $10,000 and took several weeks to manufacture in metal. MXSG printed it for $429 and completed it in one day.

"The advantage is cost and time, but our items are high-quality, too, because they are based completely on the CAD design," said Nancy Lengyel, 309th MXSG Rapid Prototyping program manager. "A prototype part, for example, can be printed overnight then checked on the aircraft to see if it will fit. If it doesn't fit, design changes are made in the CAD file, and it is printed again.

"Once the part works, it can then be machined in metal, if needed. We don't print critical aircraft parts, but 3-D printing is a great option for prototypes, tooling, fixtures, forms, jigs, plugs, covers, blast and paint masks, training aids and more."