The role of the apron is to stop the reverse. It is a part that prevents the plastic melt from leaking back during injection. During operation, the aprons are in contact with the rubber meson (passing gasket) to form a closed structure that prevents the plastic melt from leaking. The precision of the weight of an injection molding machine injection molding machine has a great relationship with the speed of over-pressure of the rubber ring and the rubber meson. The speed of a reaction through the apron is determined by factors such as its anti-reverse stroke, sealing and pressing time, and the time it takes to leave the rubber head. The combination of a good rubber head, a rubber ring and a rubber meson can achieve high precision injection volume control. Especially in the production of transparent products and precision products, the role of plastic heads, aprons and rubber mesons is reflected.