Patent ID: 6068179
Filing Date: 2000-05-30
Classification: B21D

Abstract:
A method of manufacturing a heat exchanger comprises the steps of:a) stacking two lots of three sheets of a superplastically formable metal, at least the centre sheet of each lot having had an anti diffusion bonding substance applied in desired local places,b) diffusion bonding each separate three sheet stack to form two integral structures,c) heating each integral structure to a temperature conducive to superplastic forming,d) applying an inert gas under pressure between those faying faces where anti diffusion bonding material was applied, so that those portions formed from the former outer sheets move away from the former centre sheets at those places, pulling with them the opposing portions of the former centre sheets where diffusion bonding has been effected to form a row of internal passageways,e) preparing two further sheets of a superplastically formable metal, at least one of which has a major portion of its faying face coated with a said anti diffusion bonding material such as to leave a peripheral area thereof exposed and preparing a frame formed from a superplastically formable metal,f) stacking the two, three sheet, integral structures, the two further sheets and the frame such that the two further sheets and the frame are sandwiched between the two, three sheet, integral structures,g) sealing the abutting edges of the two, three sheet, integral structures, the two further sheets and the frame to form a module,h) placing the module in an appropriately shaped die and heating the module to a temperature conducive to superplastic forming, and theni) applying an inert gas under pressure into the rows of internal passageways of the two, three sheet, integral structures and between those faying faces of the two further sheets where anti diffusion bonding material was applied, so that one of the two further sheets moves away from the other of said two further sheets, to form a single passageway centrally of the whole and to diffusion bond the two, three sheet, integral structures, the two further sheets and the frame together to form an integral module.