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Significance Statement
Vartanian and McDonald (2016) provided an industrial example of where the additive manufacturing (AM) industry is heading in order to guide further development activities in the materials community. The article published in JOM by The Minerals, Metals & Materials Society discussed the benefits of the combination of additive and subtractive metal working capabilities into one machine tool, how it came into existence and the current capabilities and advantages it offers.
The merger of AM technologies and traditional subtractive Computerized Numerical Control (CNC) methods, now known as Hybrid CNC machining, offers numerous advantages in terms of lower equipment acquisition costs, lower training time as it can be operated from a common Human Machine Interface (HMI), leverages capital assets to deploy AM technologies and provides more capabilities compared to either technology alone.
Two common methods for commercial use in laser-base AM technology are the Power Bed Fusion (PBF) and Power Fed Directed Energy Deposition (PF-DED) systems. The PBF and PF-DED systems offer different advantages; the PBF machines are better at building smaller and complex-shaped designs coupled with better surface finishes while PF-DED machines are better at building or adding materials to form large parts and repairing worn or defective metal components. The Laser Engineered Net Shaping (LENS) machines offered by Optomec are known to be a stronger candidate for PF-DED machines.
Optomec delivered a proposal to package LENS technology in a modular kit as a project call was issued to lower adoption barriers for laser metal AM. Optomec, in January 2014, were awarded an America Makes contract to package LENS technology into a modular print engine and to prove the concept by upgrading a legacy Fadel Vertical Mill into a Hybrid CNC machine tool.
Upgrading steps included interlocked access doors and ports to prevent possible exposure to the high-power laser beam in order to satisfy Class I Laser enclosure requirements, and a laser safety window for viewing the process and secondly, inclusion of a closed loop process monitoring system to control heat input and cooling rate as the AM build progresses.
The Hybrid Fadel Vertical Mill was delivered to TechSolve, a company with expertise in process improvement and CNC machines. Fast learning curve was observed as machine was installed and operational in a day despite TechSolve having no prior 3D printing experience. This was possible because the LENS Hybrid system utilizes a custom interface that enables 3D printing operations to be executed using traditional 3D CNC programing and G-codes commands already familiar to a machinist.
Live demonstration of the LENS Hybrid system by TechSolve showed the machine operating in subtractive mode as it did prior to upgrade, or in additive mode building a 3D part, or in Hybrid mode switching back and forth between subtractive and additive operations.
Repairing and selective finish machining of parts was seen as jaws of a stainless steel wrench were cut off and the resulting internal cavity of new jaws were grown back using integrated LENS printing and finish machined using the Hybrid machine’s milling capabilities.
The LENS Hybrid machine was evaluated by TechSolve to be MRL 6/7, the highest rating possible by a non-production entity. It offers enablement of the application of additive and Hybrid techniques for a wide range of structural materials at a significant lower cost.
Vartanian and McDonald (2016), noted the relevance of moving this technique forward even for AM only machines built on lower cost CNC platforms or for hybrid machines when dry machining is possible to build and finish the part on one machine. More research is required to study the thermal effects of lubricants on material microstructural integrity and how to remove resultant surface contamination prior to resuming AM operations after wet machining. However, lower cost and more flexible pathways for development and production will accelerate adoption of both additive and Hybrid fabrication methods.
REFERENCE
Optomec Additive Manufacturing Technologies and Product Offerings
Optomec is enabling new dimensions in 3D printing. Our solutions provide production grade/production scale printing of fully functional end-use devices and support a wide variety of low cost, commercially available materials used for structural metals and functional electronics printing applications. Optomec systems also enable the widest range of printed feature sizes, including support for very large meter-scale metallic structures down to very fine 10-micron scale electronic circuitry. In addition to printing full 3D structures Optomec systems can print in 3D space, enabling material to be added to existing components. With Optomec, high-volume additive manufacturing is a reality today, transforming how companies design, build and maintain critical parts and products.
Optomec introduced its first commercial additive manufacturing system in 1997 and has now installed systems at 200 customer sites in 15 countries. The company has invested more than $40 million in development, which has enabled it to bring to market unique capabilities never before possible in the 3D printing industry. Our worldwide customer base includes industry leaders in production and research in the area of additive manufacturing including General Electrics, Xerox, United Technologies, Lite-on Mobile Mechanical, Fraunhofer, and many leading universities. Optomec offers two distinct additive manufacturing technologies; Aerosol Jet technology for printing functional electronics and LENS technology for printing structural metals.
Aerosol Jet printers use proprietary technology to enable printing of micron-scale electronics in high volume and in a variety of use models, including printing circuits or components onto 2D or 3D surfaces. Our printers have been proven to meet the functionality, volume and cost demands of the Consumer Electronics Industry, particularly in mobile device and the emerging world of the Internet of Things (IoT). Aerosol Jet systems are capable of depositing a wide variety of commercially available electronic materials to produce high-resolution circuitry and functional components. Its unique aerodynamic focusing capability can precisely deposit electronic and other materials in dimensions ranging from 10 micrometers (micron) up to centimeter wide. The systems can deposit materials directly onto 3D surfaces enabling printed electronics devices such as conformal antennas, sensors, passives and active components, and interconnects within 3D IC and PCB applications. Aerosol Jet technology is available either in turnkey system configurations or as a modular print engine that can be integrated into automation platforms for high volume production applications.
LENS 3D printers use proprietary laser processing technology to print a wide range of structural metals with new levels of geometric flexibility and mechanical performance. These printers are widely used for repair, rework and coating of complex metal components in military, aerospace and general industrial markets, and well as for the production of large-scale metal components for rapid prototyping and low-volume production, thus reducing overall
product life cycle costs. LENS systems use commercially available powders to print high performance metals in materials including titanium, stainless steel and Inconel, with the quality required for critical applications. LENS 3D printers use the geometric information contained in a Computer-Aided Design (CAD) solid model to automatically drive the LENS Directed Energy Deposition process as it builds up a component layer by layer. Additional software and closed-loop process controls ensure the geometric and mechanical integrity of the completed part. LENS 3D printing technology is available either in turnkey system configurations or as a modular print engine that can be integrated into CNC machine tools for cost effective production applications.
All of Optomec systems are backed by world class customer support and service to keep your 3D printing process operating at full performance, maximizing your productivity and return on investment. To address specific customer needs, we offer a comprehensive set of service assets and support tools, both on-line and on-site.
Journal Reference
Accelerating Industrial Adoption of Metal Additive Manufacturing Technology. JOM, 2016, Volume 68, Issue 3, pp 806-810.
Optomec Corporation, Albuquerque, USA.
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