International Journal of Production Research Laser metal forming processes for rapid prototyping -A review Laser metal forming processes for rapid prototypingÐ a review

Abstract

ISSN: 0020-7543 (Print) 1366-588X (Online) Journal homepage: http://www.tandfonline.com/loi/tprs20 In the current rapid prototyping processes, a physical part of a computer model can be quickly produced for functional and dimensional veri® cation. Most of the existing systems can only produce non-metal parts, and thus limit rapid proto-typing applications. The laser-based metal forming process is a technique that has the potential to produce fully functional models directly from a CAD system and eliminate the need for an intermediate step. This paper presents a review of the state of the art laser metal forming (LMF) processes. LMF process hardware, software, and process parameters are discussed, including laser parameters, beam delivery systems, work table variables, metal deposition techniques, measurement, and control. Process limitations, materials, and costs are summarized. 1. Introduction For most manufacturers today, the key to success is to be able to satisfy customer needs by providing products in the shortest time possible and at lowest cost with better quality. Rapid prototyping (RP) is a technology initiated in the early 1980s. It is a manufacturing process that quickly produces physical prototypes directly from CAD solid models using a special class of fabrication technology. Since the intro-duction of the ® rst commercial stereolithography apparatus (SLA) in 1986, many RP systems have been developed for the growing industrial demands (Jacobs 1992). Most commercial systems use polymers of some form, and many use photopolymers. Large-scale production still requires a mould as an intermediate step before the ® nished product is realized. Some of the developing systems are capable of produ-cing direct metal prototypes while the commercial units require a polymer RP mould from which a metal casting is formed (Koch and Mazumder 1993). However, due to the increasing complexity of part geometry, producing highly accurate functional models directly from computerized data is often very di cult using available RP systems. The laser metal forming process is a techniques that has the potential to solve this problem. LENS (laser-engineered net shaping) is one developing rapid metal forming (RMF) process that has demonstrated the feasibility of laser metal forming to produce near-net-shape metal parts (Keicher et al. 1998, Beardsley 1997). Some e orts have been made to utilize the laser cladding technique, which is an established method in surface coating of metal parts, to produce metal parts by a layer additive approach (Koch and Mazumder 1993, Kreute et al. 1995). Directed light fabrication (DLF), which is being developed at Los Alamos National Laboratory, has proven capable of producing metal parts with reasonably good accuracy and improved metallurgical properties (Lewis et al. 1994).