Two projects funded by America Makes, the National Additive Manufacturing Innovation Institute (NAMII), are aimed at speeding industrial adoption of LENS metal additive manufacturing technology.

The LENS, or Laser Engineered Net Shaping process, uses a high-power laser (500W to 4kW) to fuse powdered metals into dense, 3-dimensional structures. LENS 3D printers use geometric information contained in a CAD model to automatically build up components layer by layer. Housed in a hermetically-sealed chamber which is purged with argon so that the oxygen and moisture levels stay below 10 parts per million, parts made with the process are kept clean to prevent oxidation. Metal powder feedstock is delivered to the material deposition head by a proprietary powder-feed system. Once a single layer has been deposited, the material deposition head moves on to create the next layer of an object by building up successive layers.

Finished components can then be heat-treated, Hot-Isostatic-Pressed, machined, or finished in a variety of ways to achieve the final product.

The first of the two projects led by Optomec, working in partnership with Lockheed Martin Missiles & Fire Control, MachMotion, TechSolve, and the U.S. Army Benet Laboratories, is aimed at developing a modular, cost-effective "LENS Engine" for integration with existing machine tools to enable 3D printing of metals. A hybrid system, the project will bridge the gap between subtractive and additive manufacturing processes via the latest in controls, toolpath generation and quality monitoring. The systems will be embedded in a modular design that can be retrofitted to an existing or new CNC machine tool.

For the second project, Optomec will work in partnership with Applied Optimization Inc. to develop a "process parameter knowledge base" aimed at providing defect-free 3D printing of metals using the LENS process.

This database will allow a process engineer to select from a matrix of known good process parameters. It's hoped that these "recipes" will eliminate trial-and-error process development and the instruction sets will be generated for two aerospace alloys using the physics-based simulation software, ParaGen, and then verified using deposition trials.

"The new capabilities developed under these America Makes projects will provide an evolutionary approach for industry to realize the benefits of metal additive manufacturing solutions," said Dr. Richard Grylls, LENS General Manager. "The LENS Engine will provide a low-cost entry point for 3D printing of metals because it leverages the widely available installed base of conventional machine tools, enabling additive manufacturing to co-exist with subtractive manufacturing methods."

Grylls says the project will gather as much of the known information about the LENS process technology as possible.

"The knowledge database will provide a growing repository of proven process parameters, speeding productive use of metal 3D printing with LENS," Grylls said.

Based in Youngstown, Ohio, America Makes is the pilot institute for up to 45 manufacturing innovation institutes and is a cooperative effort with the National Center for Defense Manufacturing and Machining (NCDMM).

Optomec, a privately-held supplier of Additive Manufacturing systems, is the creator of Aerosol Jet Systems for printed electronics and LENS 3D Printers for metal components.