Patent ID: 8096233

Claim:
A method of operating a servo press line in which a servo press having a slide and servo transfer devices are alternately disposed in a workpiece transfer direction, the method comprising the steps of: performing a normal press operation that adjusts a slide position of the servo press to a target slide position corresponding to a first step phase that is based on slide motion information while causing the first step phase to advance, and performing a normal transfer operation that adjusts a transfer position of the workpiece of each of the servo transfer devices to a target transfer position corresponding to a second step phase that is based on transfer motion information while causing the second step phase to advance, the second step phase being the same as the first step phase; performing a correction that delays a transfer step of one of the servo transfer devices disposed on a downstream side of the servo press as compared with the normal transfer operation when a slide upward movement step has been determined to be in a delayed state based on a current first step phase in slide upward movement and an apparent first step phase corresponding to a current actual slide position, the apparent first step phase having been calculated from the slide motion information; and performing a correction that delays a slide downward movement step of the servo press as compared with the normal press operation when an upstream-side transfer step has been determined to be in a delayed state based on a current second step phase in slide downward movement and an apparent second step phase corresponding to a current actual transfer position of the workpiece, the apparent second step phase having been calculated from the transfer motion information of the servo transfer device disposed on an upstream side of the servo press.