Patent ID: 9573183
Date: 2017-02-21
CPC Classifications: B21D,Y10T

Claim:
1. A method for forming a shell comprising: introducing material between tooling, forming the material to include a center panel, a circumferential chuck wall, an annular countersink between the center panel and the circumferential chuck wall, and a curl extending radially outwardly from the chuck wall, and selectively stretching at least one predetermined portion of the shell relative to at least one other portion of the shell to provide a corresponding thinned portion of the shell, cutting the material with a cut edge of a blank and draw die and an opposing annular cut edge die to form a blank; wherein the blank has a base gauge prior to being formed; wherein, after being formed, the material of the shell at or about the thinned portion has a thickness; and wherein the thickness of the material at or about the thinned portion is less than the base gauge; further comprising: forming the curl to include an outer lip, wherein the outer lip has a thickness substantially the same as the base gauge.