The variations of the rollover depth and burr height with the number of strikes for punching with a moving die
for v=5 mm/s are given in Fig. 4. The punched sheets were cut into half and the rollover depth and burr height
were measured at มุม=0 and 180°. The rollover depth and burr height are high for มุม=0°, whereas low for มุม=180° in
the initial stage of strikes. The variations of the rollover depth and burr height forมุม=0 and 180° are steadily
decreased with the increase in n and the rollover was measured for almost at the same depth for n=4 and above.