Rotatable stuffing device for superplastic forming and method

A method of superplastic forming of flattened metal sheets into shaped parts comprising the steps of:

• inserting the sheet onto a forming block extending upward from the upper surface of a concave forming die, heating the flattened sheet so that it drapes on the forming block, moving an upper die into a blank pre-form position and mechanically preforming the sheet by physically contacting and pulling the sheet inwardly with a roller stuffing member adjacent to the forming block, and pressurizing the upper chamber to fully form the sheet onto the surface of the forming chamber and the forming block to effect the final shaping of the part, opening the upper die with respect to the lower die and removing the shaped part from the die.

Equipment for superplastic forming of a sheet of metal into profiled parts comprising a forming die member, said forming die member having a concave shaping surface with a profiling unit that projects upwardly therefrom, a complementary gas chamber member that provides a chamber selectively pressurized with a working gas therein, said gas chamber having a rotatable blank stuffing member fixed therein, said rolling blank-stuffing member being offset from the profiling unit and which projects into the gas chamber, said blank-stuffing rolling member being adapted to contact said blank and mechanically draw said sheet inwardly to a preliminary preform position on said profiling unit, control mechanism for pressurizing said chamber so that said pressure can subsequently form said blank around said profiling unit to effect and complete formation of said part.

Superplastic forming dies including upper and lower relative movable die members, said lower die member having a concave forming surface therein and an upstanding profiling unit extending at least partly across a portion of the lower forming surface, said forming surface having an upward support surface for supporting a flattened sheet of metal plastic forming material at points between the side edges thereof, said lower die having a peripheral edge supporting said side edges of said sheet, said upper die member having a stuffing unit extending downwardly therefrom, said stuffing unit comprising a rotatable member for low-friction rolling contact with the sheet for mechanically forming the sheet into a preform, and pneumatic construction for subsequently further deforming the sheet into a fully formed part.