Patent ID: 6460394
Filing Date: 2002-10-08
Classification: B21D,Y10T

Abstract:
A method of manufacturing a heat exchanging fin having a plurality of collared-through-holes, comprising the steps of:forming a plurality of dome sections, having diameters greater than inner diameters of the collared-through-holes and which are projected from one side face of a thin plate, and a plurality of circular recesses having diameters greater than said diameters of said dome sections, each of said circular recesses enclosing one of said dome sections, the circular recesses being depressed toward an opposite face of the thin plate; forming said dome sections and said recesses into truncated cone-shaped sections having prescribed height in a plurality of steps; forming a through-hole in each of said truncated cone-shaped sections; forming edges of said through-holes into collars; and forming a flange at a front end of each of said collars.