Elevated temperature forming die apparatus

A method for making and heating an elevated temperature forming die apparatus, the method including the steps of:

• providing a matched stamping die set having a die set stroke and comprising:
• a lower die part having an upper surface configured to engage a lower surface of a first region of a sheet material workpiece;
• an upper die part supported for reciprocal motion relative to the lower die part along a first portion of the die set stroke between open and closed die set positions, the upper die part having a lower surface configured to engage an upper surface of a second region of a sheet material workpiece;
• providing at least one heater in thermal communication with one of the lower die part and the upper die part using numerical thermal finite element and optimization analysis to position the at least one heater such that a desired temperature distribution will be produced within the die set such that at least one of the forming surfaces of the upper and lower die parts is maintained within a predetermined temperature range;
• maintaining at least one of the lower surface of the upper die part and the upper surface of the lower die part within a predetermined temperature range by controlling power application to the heaters;
• and
• providing a third die part having an upper surface configured to engage a lower surface of the second region of a sheet material workpiece whose first portion is positioned between the upper and lower die parts, supporting the third die part for reciprocal motion relative to the upper die part such that closure of the upper die part along the first stroke portion against the third die part will clamp the first portion of the workpiece between the upper and third die parts, and further supporting the third die part for reciprocal motion relative to the lower die part such that, once the first portion of a workpiece has been clamped between the upper and third die parts a draw region of the workpiece extending adjacent an interface between the first and second portions of the workpiece can be drawn in-plane by displacing the lower die part relative to the clamped-together upper and third die parts along a second portion of the die set stroke.