Manufacturing is changing. While we’ve come a long way from the human-intensive times of the 1930s, when automotive assembly required extensive participation from workers (www.plantservices.com/multimedia/2013/manpower-behind-horsepower), organizations such as America Makes, the National Additive Manufacturing Innovation Institute (www.namii.org), are leading the revolutionary charge onto the shores of 3D printing. “You can manufacture things in ways you never could before,” said Lonnie Love, manufacturing systems research group leader at Oak Ridge National Laboratory (ORNL, www.ornl.gov), during his recent presentation at the Fluid Power Systems Conference in Rosemont, Illinois.
Morris Technologies, a division of GE Aviation, is using additive manufacturing to produce 35,000 fuel-injection nozzles for inclusion in the CFM LEAP engine (www.plantservices.com/articles/2013/11-from-the-editor-new-manufacturing). The revolution has begun. And the armory is located in Oak Ridge, Tennessee, where the U.S. Department of Energy's Manufacturing Demonstration Facility is located.
“In most manufacturing, you're removing material,” explained Love. “In additive manufacturing, you're adding material to make the part. We have nine metal machines. We have an electron beam melting system. An electron beam melts the particle/powder (http://www.youtube.com/watch?v=BxxIVLnAbLw). You're spreading the heat out. It’s precision melting of powder materials.”
Another of the machines at ORNL is the ultrasonic additive manufacturing. “Instead of fully additive, this puts down a strip of metal and welds it together and then a CNC cuts the metal,” explained Love. “This is an additive and subtractive process. There's some waste, but it's a low-temperature process so you can embed sensors and wires and fibers.”
“With laser metal deposition, you can blend materials, unlike the first two types,” said Love. “This is site-specific material addition, which allows for the application of advanced coating materials for corrosion and wear resistance.”
Other additive manufacturing machines at ORNL include the laser powder bed, laser sintering, fused deposition modeling, and stereolithography. There’s more than one way to print a part.
Desktop 3D printing, made available in schools and homes, is the next wave.
“The clone wars happened in the late 1980s when companies came out with personal computers,” said Love. “It changed our world. It's happening right now. Stratasys (www.stratasys.com) had the patent for three dimensional modeling. The patent ran out three years ago.” And new innovations from Stratasys continue spur litigation, including a recent suit against rival Affinia (http://www.3ders.org/articles/20131125-stratasys-brings-patent-infringement-suit-against-afinia.html).
“One of the big challenges is you're melting the metals and then they're cooling,” explained Love. “Neutrons penetrate anything. So we can get thermography. Laser additive manufacturing creates large residual stress leading to distortion. We're looking at understanding the limits of mechanical strength. Less mass means less material, less energy, faster build, and lower cost. Blending hydraulics and additive manufacturing means mesh structures for weight reduction.” The difficulty is that very little research funding is available for hydraulics.
“There's a lot of potential in the polymer area,” said Love. “The strength-to-weight ratio can shoot through the roof if you have the right additives.”
Size also matters with additive manufacturing. “We're going really big, really fast with 3D printers,” said Love. “There's an interesting trend going on. Big manufacturers are thinking it's time for them to go in. Cincinnati (www.e-ci.com) is working with ORNL to create a product for tooling. It’s got a work volume of 8-by-8-by-8-ft gantry with a Kuka robot.” Big area additive manufacturing (BAAM) is just around the corner. Cincinnati and Lockheed Martin are working on a 20-by-20-ft product line, too.
“Tooling is an expensive endeavor with long lead time,” said Love. “A large-scale deposition system provides unbounded build envelope, high deposition rates, and direct build components, tools, dies, and molds. Carbon fiber material reduces warping out of oven. If we put in 5-10% carbon fiber, it changes everything. It increases the strength of the material, and it changes the thermal conductivity, so it doesn't curl up when it comes out and cools.”