The purpose of tray packaging for food three-piece cans is to facilitate the transfer, storage, and unstacking of empty can products from the canning workshop to the food and beverage filling workshop. It aims to prevent product damage, moisture, rust, and external contamination during the transfer process, ensuring that the performance of the product meets customer requirements and safely arrives at the food and beverage filling workshop.

The packaging process for three-piece cans mainly involves tray stacking and packaging equipment and materials. The packaging equipment includes stacking machines, automatic packaging machines, PE film wrapping machines, or heat shrink machines, while packaging materials include bottom pallets, neutral liner paper, pressure plates, strapping belts, PE wrapping film, or heat shrink film.

Stacking machines are divided into two types: layer-by-layer automatic stacking (where the pallet automatically descends one level after each layer of empty cans is fed) and layer-by-layer electromagnetic stacking (where the pallet remains stationary, and entire layers of empty cans and neutral paperboard used as separators are conveyed onto the fixed pallet by electromagnetic suction plates and pneumatic suction cups). The former is more widely used in the industry.

The process of automatic stacking and packaging involves the stacking machine completing the required number of stacks. During this process, a layer of neutral paperboard is placed on the pallet surface, between each layer of empty cans, and under the pressure plate. After manual placement of the pressure plate, the stack is lowered and transported to the packaging area. Then, it is strapped with packaging belts manually or automatically using a packaging machine in both longitudinal and transverse directions. Subsequently, it is conveyed to the film wrapping area, where it is wrapped from top to bottom using a PC film automatic wrapping machine or bagged using a bagging machine. Finally, it is passed through a heat shrink machine for film shrinking, completing the entire packaging process in one cycle.

Strict control over the selection of packaging materials and the stacking and packaging process is essential to maintain product performance and packaging quality throughout the entire circulation process of packaging, storage, and transportation.