David Gurrola, a former an engineer with Northrop Grumman and Parker Aerospace, saw a gap between the parts traditional machining could produce and what aerospace engineers really wanted, a gap he thought could be filled with additive technology.  “Aerospace companies are constantly battling a break point where they can’t get drastic increases in efficiency due to standard manufacturing practices,” says Gurrola, who founded GROWit (www.growit3D.com; Anaheim, CA), which provides rapid prototyping/manufacturing services.  “These additive technologies are bringing in a whole new thought process on how to think more efficiently.”  For example, he points out that designers are no longer limited to what a lathe or a mill can do.

The GROWit team mainly relies on the Connex500 3D printer from Objet and M270 Direct Metal Laser Sintering systems from EOS to produce multi-material and metal aerospace parts, for both production prototyping and quality/durability validation testing.

One example is onboard heat exchangers, which require multiple and complex cooling paths. Traditional machining creates 90° angles to flow fluid, i.e., hot air, around various components, but additive machinery can form parts with more subtle curves for more efficient flow and heat dissipation, Gurrola says.

Another example is modifying injection mold tools to speed up parts’ cooling time.  Most injection mold tools are constructed with cooling channels that consist of a hole or two, which means material closer to that channel cools faster than other places in the molded part, thus requiring the mold to stay shut longer so that the entire part can cool.  Additive technologies can create tools with multiple cooling channels that conform to the shape of the part, without sacrificing mold integrity.

“If you’re doing 100 molds, it’s not that big a deal [to use older technology], but if you’re doing a hundred thousand of them, that adds up,” he says.--SEA