From technology push,to industrial pull: superplastic forming and diffusion bonding using lasers

The process of Superplastic Forming (SPF) has produced a vast number of components, from simple shapes to those with complex geometric features, all to a dimensional accuracy difficult to obtain by traditional sheet metal methods. When used in conjunction with Diffusion Bonding (DB), extraordinarily lightweight, stiff, strong and fatigue enduring components and structures can be manufactured that are virtually impossible to produce by any other means. However, SPF/DB is often criticised as too complicated, expensive, slow and unstable, a reputation that has contributed to its use being largely confined to manufacturing when no other means of production can be found. Perhaps, the fundamental cause of this negative perception of SPF/DB is the fact that derivatives of mid 18^th century hydraulic presses are used, virtually universally, that provide only a single temperature to the work piece, which is heated primarily through conduction, a form of heating which is slow and expensive. By comparison, modern, electrically efficient, lasers, if used to directly heat the work piece, could transform SPF/DB into a mainstream process and the first choice of designers. This paper compares, and contrasts, the two systems.