| 摘要 |
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. Forming gas, such as argon, flows from a bottle 51 through a pressure regulator 55 and a gas mass flow meter 57 to an input port 75 in the lid 67 of a forming die 61. A metal sheet 71 to be formed is trapped between the periphery of the lid 67 and the walls of a bottom section 69 of the die. An exhaust port 79 in the bottom section 69 allows gas between the sheet 71 and the bottom section 69 to escape as the forming gas superplastically forms to sheet 71. A pressure gage 59 indicates the forming pressure. 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. The method may also be used to form cells of multiple sheet panels from a stack of sheets. |
