B. Dutta, V. Singh, H. Natu, J. Choi, J. Mazumder, POM Group, Inc., Auburn Hills, MI
Direct Metal Deposition (DMD) is a Laser Aided Manufacturing (LAM) technique commercialized by The POM Group Inc. which is used in repair and restoration of high performance nickel and cobalt superalloys in the aerospace industry. DMD provides a promising solution for hard to weld gas turbine components which are manufactured from directionally solidified(DS) or single crystal (SX) alloys. Examples of such components are gas turbine blades and stator vanes segments. DMD can also be used in providing OEM solutions such as welding of Z-notches in new gas turbine blades. Recent developments in the DMD process has allowed extended capabilities to control microstructure, minimize the heat affect zone(HAZ)and provide near net shape with the integration of new technological advanced laser systems such as the disc laser. With the integration of disc lasers and proprietary POMs’ software, DMD can achieve fine laser cladding of features with magnitude of 200 microns. Moreover DMD with the use of proprietary sensor technology controls the heat input into the part in real time. This technology has proven its use in DS and SX alloys where issues such as recrytallization of the base alloy cannot be tolerated. Besides rebuilding and used component, DMD technology has also been proven in hardfacing applications for gas turbines such as Z-notch welding with alloys such as Stellite 6 and Stellite 694. The near neat shape and the minimum heat input keep the cost of post processing and distortion to a minimum in such restored parts.
Summary: The present paper focuses on Direct Metal Deposition (DMD) technology as an advanced laser aided manufacturing technology for the aerospace and defense industries. It provides a brief introduction in the DMD technology, the recent advancements in the commercial DMD Systems ( 5 Axis and Robotic Systems) and patented software advancements for DMD ( DMDCAM and DMDVision). DMDVision is unique software developed for the gas turbine industry to provide a turn-key solution for manufacture and restoration of OEM gas turbine components such as turbine blades. Finally the paper discusses POM’s experience with various aerospace alloys families such as Inconel, Stellite, Waspalloy and Titanium based Alloys.
