A shrink packaging machine is a machine in which a product is wrapped with a heat shrinkable film and then heated to shrink the film to wrap the product. According to the type of machine is divided into drying tunnel type shrinking machine, oven type shrinking machine, frame type shrinking machine, gun type shrinking machine. Automatic shrink packaging machine is a kind of automatic packaging equipment that combines pneumatic components and mechanical devices and is controlled by PLC and other peripheral circuits. The actuator of this equipment is the cylinder. It is controlled by the two-position and five-way electromagnetic valve. The working position of the cylinder is detected by the magnetic switch and the proximity switch and fed back to the PLC. The PLC sends the control command to the solenoid valve of the corresponding cylinder through the program. To control the operation of the cylinder.