Patent ID: 6016603
Filing Date: 2000-01-25
Classification: B21D,B60G,B62D,Y10T

Abstract:
A method of hydroforming a closed channel structural member comprising the steps of:(a) disposing the closed channel structural member within a die cavity of a first hydroforming die defining a perimeter that is larger than the perimeter of the closed channel structural member;(b) performing a preliminary hydroforming operation to expand the closed channel structural member into conformance with the die cavity of the first hydroforming die such that the perimeter of the closed channel structural member is increased;(c) disposing the closed channel structural member within a die cavity of a second hydroforming die defining a perimeter that is approximately the same as the perimeter of the closed channel structural member; and(d) performing a final hydroforming operation to deform the closed channel structural member into conformance with the die cavity of the second hydroforming die such that the perimeter of the closed channel structural member remains approximately the same.