Thinning extension die

The thinning extension die comprises an upper die body and a lower die body, and an extension male die body is arranged in the center of the upper die body; the lower die comprises a discharging plate, a lower die base and an elastic ejector structure, the discharging plate is installed above the lower die base in a liftable mode, a hole is formed in the center of the discharging plate, and the size of the discharging plate is matched with the size of the extending male die. A female die plate is installed on the upper surface of the lower die base, a female die insert is installed in the center of the female die plate, a hole is formed in the center of the female die insert, the size of the hole is larger than that of the hole formed in the center of the discharging plate, and an inner cavity of the stretching male die and an inner cavity of the female die insert are matched to form a forming space of a to-be-stretched part. An elastic ejector base plate of the elastic ejector structure is installed below th