Patent Number: 6,305,203

Title: Controlling superplastic forming with gas mass flow meter

Abstract: The forming time necessary to superplastically form an object from a metal sheet is estimated by empirical analysis. The required rate of gas mass flow into a forming cavity is then determined using either a nomograph composed of four interrelated graphs, or a single graph which requires the input of fewer variables than the nomograph. The present invention may also be used to form cells of multiple sheet panels from a stack of sheets. In the latter application, forming time necessary to complete forming of the cells from an interim point where the core sheet forming pressure and the die temperature are increased from interim levels to their final values is estimated by empirical analysis. A nomograph or single graph of the present invention then determines the gas mass flow rate necessary to safely and efficiently complete forming of the cells from the foregoing interim point. In both of the foregoing embodiments, the required gas mass flow rate, which is a target value, is maintained by regulating the forming pressure until the final forming pressure is reached.

Inventors: Yasui; Ken K. (Huntington Beach, CA)

Assignee: McDonnell Douglas Corporation

International Classification: B21D 26/02 (20060101); B21D 26/00 (20060101); B21D 026/02 ()

Expiration Date: 10/23/2018