| 摘要 |
A punching die for punching out a seal member from a sheet of an inorganic fiber mat having a contour. The punching die includes a base plate. A first blade is supported on the base plate and has a cutting edge extending to form a loop. The first blade punches out a frame-shaped unnecessary portion, which includes the contour, and a seal member formation portion, which includes the seal member, from the inorganic fiber mat. A second blade, which is supported on the base plate at an outer side of the first blade, partially cuts the frame-shaped unnecessary portion. The at least one second blade forms a perforation in the frame-shaped unnecessary portion to separate the unnecessary portion into a plurality of unnecessary fragments. This improves productivity for production of the seal members.
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