1. PUBLISHED BY THE AMERICAN WELDING SOCIETY TO ADVANCE THE SCIENCE, TECHNOLOGY, AND APPLICATION OF WELDING AND ALLIED JOINING AND CUTTING PROCESSES WORLDWIDE, INCLUDING BRAZING, SOLDERING, AND THERMAL SPRAYING March 2014 42017:Layout 1 3/18/14 7:56 aM Page C1

2. I f youre a manufacturer, youve likely heard the term additive manufactur- ing or 3D printing too many times to count over the past year. The process involves making a three-dimensional solid object of virtually any shape from a digital model. It is achieved using an ad- ditive process, where successive layers of materials are deposited in different shapes. This differs from traditional man- ufacturing techniques, which mostly rely on the removal of material, such as cut- ting or drilling (subtractive processes). Objects that are manufactured additively can be used anywhere throughout the product life cycle, from preproduction (i.e., rapid prototyping) to full-scale production (i.e., rapid manufacturing), in addition to tooling applications and postproduction customization, such as repairs. As you can imagine, there are numer- ous additive manufacturing approaches being used and tested all over the world. Fused-deposition modeling (FDM) is the popular extrusion approach that has been a hit with manufacturers who produce small thermoplastic products and parts that typically fit in the palm of your hand. Taking the Next Step in Additive Manufacturing RICHARD MARTUKANITZ, PhD, is director, Center for Innovative Materials Processing through Direct Digital Deposition, Applied Re- search Laboratory, Pennsylvania State Univer- sity, State College, Pa. JAY HOLLINGSWORTH is director, Public Relations, Phillips Service Industries, Inc. Large, high-value metal structures are the next big prize for additive manufacturing BY RICHARD MARTUKANITZ AND JAY HOLLINGSWORTH Fig. 1 An example of a three-dimensional shape produced by additive manufactur- ing. (Photo courtesy of Lockheed Martin) 42017:Layout 1 3/18/14 7:56 aM Page 40 3. Selective laser sintering (SLS) is a popu- lar granular (powder-based) approach that has produced a variety of small to medium-sized metal and ceramic items for manufacturers in a wide range of industries. Companies like Stratasys, which man- ufacture 3D printers to build objects rep- resenting complex geometries in a wide range of thermoplastic materials, have achieved significant mainstream success and media attention with their additive manufacturing processes. However, one has to wonder: Whats the next big prize for additive manufacturing? Large, high-value metal structures will be the holy grail for additive manu- facturing practitioners, said Chris Cor- nelius, director of Federal Business De- velopment at Phillips Service Industries, Inc. Manufacturers that rely on expen- sive metals like titanium, tantalum, and nickel-based alloys know how timely and costly it is to work with these difficult al- loys using traditional forging processes. An approach that is cultivating a lot of attention is the category of additive manufacturing processes referred to as directed energy deposition, which typi- cally uses a laser (directed laser deposi- tion) or electron beam (directed electron beam deposition) to repetitively melt and deposit layers of a metal, thus building three-dimensional shapes Fig. 1. These processes are capable of produc- ing relatively complex shapes that require minimal machining to achieve final di- mensions. Because these processes add material selectively, they offer promise in dramatically reducing material and machining costs associated with the fab- rication of large structures. The development of additive manu- facturing techniques relevant to building large structures within the United States may be traced back to early development efforts at Sandia National Laboratory, the Applied Research Laboratory at Penn State, and Sciaky, Inc., Chicago, Ill. Sciaky is a pioneer in electron beam welding technology. In the late 1990s, the company began exploring the use of high- energy electron beams for additive pro- cessing. The approach was introduced to the mainstream market in 2009. It com- bines computer-aided design (CAD), electron beam welding technology, and wire feedstock. In short, a free-moving electron beam welding gun deposits ma- terial, such as titanium, layer by layer onto a substrate plate (of the same ma- terial) until the structure reaches near- net shape. The entire process takes place in a vacuum chamber, which protects the selected material from external impuri- ties. After the structure reaches near-net shape, it undergoes minor postproduc- tion machining until it reaches its com- pleted state. To date, the Sciaky process, referred to commercially as electron beam direct manufacturing (EBDM), is the only additive manufacturing ap- proach that has produced metal struc- tures more than 10 feet long. The progression of the EBDM process is as follows: from CAD file, to part buildup on a substrate plate, to near-net shape, to finished part (after minor postproduction heat treatment / machining) Fig. 2. According to Sciaky, the EBDM process with its VX-300 electron beam welding chamber (Fig. 2) has a standard build envelope of 19 x 4 x 4 ft (L x W x H), which allows manufacturers to produce very large structures/parts, with virtually no waste. Deposition rates typically range from 7 to 20 lb per hour, depending upon part geometry and the material selected. A dual wire-feed system can be utilized with the process (Fig. 3) to increase depo- sition efficiency, as well as to easily switch to different deposition materials. In summary, the benefits of EBDM, when compared to traditional manufac- turing and prototype processes, are sig- nificantly reduced material costs, lead Fig. 2 The progression of the electron beam direct manufacturing process. A CAD file; B part buildup; C near-net shape; D finished part. (Photo courtesy of Air Force Research Laboratory (AFRL)) A B C D 42017:Layout 1 3/18/14 7:56 aM Page 41 4. times, and machining time. AeroMet Corp., Eden Prairie, Minn., in the mid-1990s provided the first com- mercial capability for large-scale builds using the directed laser deposition process. AeroMet, which was a subsidiary of MTS Corp., commercialized technol- ogy developed by the Applied Research Laboratory at Penn State and Johns Hop- kins University under sponsorship from the Defense Advanced Research Project Agency (DARPA). The AeroMet process utilized powder as the feed material along with an 18-kW CO2 laser to build structures up to several feet in size. In the early 1990s, Sandia National Labo- ratory developed the Laser Engineered Net Shaping (LENS) process utilizing lower laser power with powder additions. Several companies have developed and advanced laser and powder deposition within the United States for relatively large build sizes. This includes Optomec, Inc., which commercialized the original LENS technology, DM3D, Inc. (formerly POM), and RPM Innovations. An ad- vancement introduced by Optomec, Al- buquerque, N.Mex., was a large build en- velope system added to the product line. Its LENS 850R system (Fig. 5) has been commercially available since 2004. RPM Innovations, Rapid City, S.Dak., has also developed large-build capability with its system. Using an innovative powder feed- ing system, RPM Innovations technology enables large build volumes while pro- viding relatively good surface and fea- ture quality Fig. 6. The companys largest system is able to produce parts on the order of 5 x 5 x 7 ft. So, the race to produce large struc- tures through additive manufacturing has begun, and the current front runner is electron beam deposition technology. Through years of testing and devel- opment, the electron beam direct manu- facturing process has proven to produce strong, high-purity parts, and its cer- tainly less messy than powder-based ap- proaches, said Kenn Lachenberg, Ap- plications Manager at Sciaky, Inc. The most important factors are part quality and process repeatability. Over the past three years, technology- driven organizations like the U.S. De- partment of Defense (DoD), Lockheed Martin Aeronautics, Penn State Univer- sity, DARPA, and the Tank Automotive Research, Development and Engineer- ing Center (TARDEC), a United States Army laboratory, have entered into re- search and development projects to ex- plore the viability of the EBDM process. At the end of 2011, Sciaky entered a DoD Mentor-Protege Agreement with the Aeronautics business area of global security giant Lockheed Martin to ad- vance Sciakys EBDM technology. The DoD and the manufacturing industry identified EBDM for repair and discrete part production as a game changer, meaning it could redefine and advance the current state of the art in aerospace manufacturing. While the early focus is going to be the F-35, we ultimately plan to imple- ment EBDM technology across the breadth of our aircraft product lines to improve affordability and lead time for titanium structures, said Brian Rosen- berger, Affordability Lead for Improve- ments & Derivatives at Lockheed Mar- tin Aeronautics. In 2012, Sciaky partnered with the Center for Innovative Metal Processing through Direct Digital Deposition (CIMP-3D) at the Pennsylvania State University to advance Direct Digital Manufacturing (DDM) technology, via funding from DARPA. The mission of the Fig. 3 A dual wire system increases deposition efficiency. (Photo courtesy of Sciaky, Inc.) 42017:Layout 1 3/18/14 7:56 aM Page 42 5. Fig. 4 The large electron beam welding chamber on the VX-300 allows the manufacturing of large parts. (Photo courtesy of Sciaky, Inc.) Fig. 5 The Optomec LENS 850R system has five axes of motion and a build envelope of approximately 3 x 5 x 3 ft. Fig. 6 The directed laser deposition process developed by RPM Innovations for building relatively large, complex shapes. 4 5 6 42017:Layout 1 3/18/14 7:56 aM Page 43 6. center, which operates a state-of-the-art additive manufacturing demonstration fa- cility, is to advance and deploy DDM tech- nology for highly engineered components for the DoD and U.S. industry. Michael Maher of DARPAs Open Manufacturing Program stated, Addi- tive manufacturing, when properly im- plemented, has the potential to dramati- cally impact manufacturing cost and lead times for DoD systems; this means ad- dressing issues such as process capability, design requirements, and qualification and certification methodologies up front. In 2013, Sciaky entered into a Coop- erative Research and Development Agreement (CRADA) with TARDEC. The CRADA centers on four primary thrusts. The first is investigating new processes for joining armor. The second is blending (grading) metals to improve part life and performance. The third is discrete, on-demand metal part produc- tion using Sciakys EBDM process. The fourth is part repair and overhaul. In a nutshell, EB welding and EBDM processes will be used to support critical military weaponry, while significantly cutting material costs and usage, supply schedules, and design time. While additive manufacturing is be- coming more mainstream each passing year, there is still work to be done on per- fecting the process of producing large- scale, high-value parts. Like all great in- novations, the right resources will need access to the right tools. With additive manufacturing, new ground is being paved every day, said Cornelius. If full potential is ever achieved, Americas manufacturing in- dustry will soar to new heights. Reprinted with permission from WeLdIng JouRnaL, March 2014. on the Web at www.aws.org. american Welding Society. all Rights Reserved. Foster Printing Service: 866-879-9144, www.marketingreprints.com. 4915 W 67th Street Chicago, IL 60638 877-450-2518 www.sciaky.com 42017:Layout 1 3/18/14 7:56 aM Page 44