The gap value between the punch and the die varies according to the material and thickness: for example, the material thickness of low carbon steel and brass is 0.4~ 1.2mm, and the gap value is 7%~ 12% of the thickness (both sides), while the gap value of hard steel is 10% ~ 65400% of the same thickness. The material thickness is 1.2~2.5mm, the gap value is 9%~ 12% of the thickness (bilateral), and the gap value of hard steel is 18%~25% (bilateral); The material thickness is 2.5~4mm, and the gap value is 12%~ 16% of the thickness (bilateral), and the gap value of hard steel is 15%~28% (bilateral); The thickness of the material is 4~6mm, and the gap value is 15%~ 18% of the thickness (bilateral). The gap value of hard steel is 27%~29% (bilateral). The gap value has nothing to do with the size of the material area, but only with the thickness and hardness of the material. In case of fine blanking, the gap value is 1% of the material thickness (bilateral).