Reverse stretching forming system of safety airbag generator shell

The invention provides a reverse stretching forming system of a safety airbag generator shell. The reverse stretching forming system of the safety airbag generator shell is characterized by comprisinga first stretching device, a second stretching device, a third stretching device and a fourth stretching device which are sequentially arranged; the first stretching device comprises a first fixing part and a first stretching part; the second stretching device comprises a second fixing part and a second stretching part; the third stretching device comprises a third fixing part and a third stretching part; the fourth stretching device a fourth fixing part and a fourth stretching part; it is set that the stretching distance of the first stretching par is a; it is set that the stretching distance of the second stretching par is b; it is set that the stretching distance of the third stretching par is c; it is set that the stretching distance of the fourth stretching par is d; and a