In a cutting die having a cutting chip, applied to a punch press, and cutting a work in collaboration with a cutting punch, a resistance member for guiding swarf generated during cutting of the work through the cutting chip and dividing it by giving resistance to it is provided around a scrap discharge hole so that the divided swarf does not remain in the scrap discharge hole but is discharged to an outside so as to prevent clogging by scrap.

In a cutting die having a cutting chip, applied to a punch press, and cutting a work in collaboration with a cutting punch, a resistance member for guiding swarf generated during cutting of the work through the cutting chip and dividing it by giving resistance to it is provided around a scrap discharge hole so that the divided swarf does not remain in the scrap discharge hole but is discharged to an outside so as to prevent clogging by scrap.

A bipolar plate having a surface structure for a flow field, inner forms such as holes and slots in the plate, and a reference geometry on the outer form thereof is produced by means of a hydraulic fine-blanking press having an at least three-stage progressive die, in the first stage of which a blank is cut partially free from a metal-foil strip, subsequently in a second stage the surface structure is formed in the connected blank via compression-forming using a forming force of at least 2500 to 3500 kN, the inner form, the slots and the reference geometry are formed by way of cutting in, and on, the blank and then, in a third stage, cutting of the outer contour and removal of the finished blank in the form of the bipolar plate are carried out successively in the stroke cycle.

In a back pressure device for progressive die apparatus, a suitable back pressure can be produced during the blanking interval preventing the iron core laminates from being pushed upward by using a simple structure. The back pressure device for progressive die apparatus comprises a support table (31) disposed in a vertically moveable manner in an iron core retaining member (22) for retaining iron core laminates blanked from the sheet steel strip in the progressive die apparatus (1) and for stacking the iron core laminates thereon one after another, a support unit (32) for supporting the support table, a lifting motor (33) for causing a vertical movement of the support table via the support unit and a control unit (34) for controlling a rotational motion of the lifting motor, wherein the control unit is configured to set a plurality of torque limit values for limiting an output torque of the lifting motor depending on an action of the progressive die apparatus so that the output torque is limited by a largest of the torque limit values during a blanking interval for the iron core laminates.