Applications of a Hybrid Manufacturing Process for Fabrication and Repair of Metallic Structures

Abstract

Since its appearance, rapid prototyping technology has been of interest to various industries that are looking for a process to produce/build a part directly from a CAD model in a short time. Among them, the direct metal deposition process is the only process which directly manufactures a fully dense metal part without intermediate steps. However, challenges of the direct metal deposition process include building overhang structures, producing precision surfaces, and making parts with complex structures. Coupled between the additive and the subtractive processes into a single workstation, the integrated process, or hybrid process, can produce a metal part with machining accuracy and surface finish. Therefore, the hybrid process is potentially a very competitive process to fabricate and repair metallic structures. This paper summarizes the current development of the hybrid process to process high temperature metallic materials, including tool steel and Ti64. Research in simulation and modeling, process development, and actual part building and repair are discussed. Introduction For more than a decade, layered manufacturing technology, also known as Rapid Prototyping (RP) has given industry an approach to achieve the goal of providing products in a shorter time and at a lower cost. Most of the current RP systems are built on a 2.5-D platform. Among them, the laser-based deposition process is a potential technique that can produce fully functional parts directly from a CAD system and eliminate the need for intermediate steps. However, such a process is currently limited by the need for supporting structures – a technology commonly used in all the current RP systems. Support structures are not desirable for high strength and high temperature materials such as metals and ceramics since these support structures are very difficult to remove. Multi-axis systems can offer much more flexibility in building complex objects. Laser aided RP is advancing the state-of-the-art in fabrication of complex, near–net shape functional metal parts by extending the laser cladding concept to RP. The Laser Aided Manufacturing Process being developed in the Laser Aided Manufacturing Processes (LAMP) Laboratory at the University of Missouri-Rolla (UMR) combines laser deposition and machining processes to develop a hybrid rapid manufacturing process to build functional metal parts. This paper summarizes the research and applications of such a hybrid process for fabrication and repair of metallic structures. A Hybrid Manufacturing System In order to expand the applications of metal deposition processes, multi-axis capability is greatly needed. A multi-axis rapid manufacturing system can be hardware-wise configured by adding extra degrees of mobility to a deposition system or by mounting a laser deposition device on a