US 6,305,203 B1 · 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.

Claims12

Dependent claims

A method for controlling the superplastic forming of at least one metal sheet into an object having a shape, comprising the steps of:

positioning at least one metal sheet in a forming die;
providing means for fluidly communicating a forming gas into the forming die at an actual gas mass flow rate;
providing means for regulating the actual gas mass flow rate;
providing means for measuring the actual gas mass flow rate;
providing means for determining a target gas mass flow rate for the actual mass flow rate;
providing means for comparing the actual gas mass flow rate with the determined target gas mass flow rate;
creating a forming pressure in the forming die by fluidly communicating forming gas into the forming die, so as to provide a differential pressure across the said metal sheet effective to deform the sheet;
comparing the actual gas mass flow rate with the determined target gas mass flow rate;
and
adjusting the actual gas mass flow rate at the regulating means effective to minimize the difference between the actual gas mass flow rate and the target gas mass flow rate, to control the deforming of the sheet,
wherein the comparing and adjusting steps effect a feedback loop including said comparing means and said adjusting means.

8 more elements

Dependencies are inferred from the claim text.

Controlling superplastic forming with gas mass flow meter

Life of this patent

Controlling superplastic forming with gas mass flow meter

Life of this patent

Abstract

Claims12