According to the different stretching methods of the wrap packaging equipment, the machines can be divided into two categories: “pre-stretching” type and “post stretch” type:
(1) Pre-stretched wrapping machine: refers to setting the stretching ratio of the wrapping film in advance, then stretching the wrapping film under the action of the pre-stretched film frame mechanism, and finally wrapping it on the goods to be packaged. The advantage is that it can spread the film evenly, has a beautiful appearance after packaging, is highly adaptable (can be used for special goods such as ultra-light and ultra-high height), and can save a lot of wrapping film under the same conditions.
(2) Post-stretch type wrapping machine: refers to making the goods rotate faster than the speed when the stretch film is pulled out (achieved by adjusting the friction damping of the anti-stretch mechanism), so that the stretch film can be wrapped while being pulled out onto the goods. Because the damping can be adjusted arbitrarily, any quality stretch film or ordinary plastic film can be used. However, for lighter and taller goods, stable packaging cannot be achieved, and the consumption of film is large.
Wrap packaging machines can be divided into the following three types according to their basic structure:
(1) Simple type: The wrapping and packaging process is controlled manually. Goods packaging speed is low. The rolling carriage speed, turntable/arm speed, etc. cannot be adjusted. When packaging, the overlap height of the film, the amount of flanging, the number of winding layers and the height of the goods to be packaged are all controlled by manual operations. And it cannot be connected to the production line.
(2) Semi-automatic type: The wrapping and packaging process is controlled manually and machine-wise. Goods packaging speed is low. The mixing carriage speed, turntable/arm speed, etc. can be adjusted at any time. When packaging, the overlap height, flanging amount, number of wrapping layers and the height of the goods to be packaged can be set in advance, and a program can be formed to automatically wrap the goods.
(3) Fully automatic type: The wrapping and packaging process is automatically controlled by the machine (i.e. production line type). The packaging speed of goods is higher. This type of packaging machine is directly connected to the conveyor belt on the production line. The wrapping and packaging process is controlled by the main control machine on the production line. The movement of the goods to be packaged and the movement of the conveyor belt are uniformly controlled, and the packaging position can be automatically positioned; all The adjustment parameters are all pre-set, and the cutting and control of the stretch film are fully automatic; and there are supporting safety facilities to ensure the personal safety of the staff.
The fully automatic rotary arm stretch wrapper is just the typical model of fully automatic machines. The fully automatic rotary arm stretch wrapper is mainly suitable for modern wrapping operations with large production volume and high logistics efficiency to meet the packaging requirements of lighter or heavier goods. Different packaging systems can be customized according to the actual needs of different products and sites, and can automatically complete the entire process of loads sensing, centering, covering and wrap packaging, transportation, and film loading and cutting. The conveying method can adopt different forms such as Tori, chain, chain plate, belt, etc. It is widely used in industries such as food, beverage, chemical industry, building materials, papermaking, etc. that require high packaging efficiency and require a top film to be covered.