You didn't say the material thickness, assuming it is 0.5mm iron, then the unilateral clearance between the punch and the knife edge is 0.03. According to the principle of inner hole drilling, the sizes of three circular holes are 4.0820.169.10, respectively. Then the aperture of the lower die blade is 4.14 20.229.16 respectively; The shape needs to be redrawn according to the dimensional tolerance. R5 on the left becomes R4.96, R 12 on the right becomes R 1 1.90, and the left and right horizontal lines are connected with the left and right R arcs respectively. The big R in the middle can be set to 36. 16, and R4 connected with the big R arc becomes R60 on the right side of R3.90 The shape thus drawn is the theoretical value of the size of the product. The shape is blanking, so the drawn shape is taken as the edge shape of the lower die, and the offset command and internal offset of 0.03 are the shape and size of the punch. The hole spacing of the three centers can be designed according to the median value.