The most important consideration in the design of a pressure pad for fineblanking die is the special construction required to lock the workpiece tightly against the die and force the metal to flow against the punch. A v shape impingement ring is provided on the pressure pad surrounding the out line of the part. This v impingement ring fully penetrates into the scrap metal out side the shear line during blanking.

The out line of an impingement ring is a closed shape conforming to that of the blank to be produced. In general, the height of the v ring ( Penetration ) is of 20% of the stock material for low ductile material. The more ductile material require a penetration of 32-35 % of the stock thickness.

If the ring is to be used on both side of the stock, the height of each ring should be half the penetration required for the metal.

In the fine blanking die, the v ring is use on both the pressure pad and the die plate when the material thickness is more the 4mm. The single v ring is use in the fineblanking die when the stock material is equal or lesser than 4mm.

Detail dimension of V impingement ring is listed in the following table.