A canned container made of tinplate usually needs to be coated with a certain coating on its inner surface. The purpose is to prevent the chemical interaction between the contents of the can and the wall of the can and the contamination of the contents by trace harmful substances, and to protect the freshness of the contents. As well as the original flavor, the starting food can be stored, transported and sold for a long time without affecting its edible value.tinplate suppliers
The principle of coating：
The inner surface of the can container is coated with a coating that is applied to the smooth surface of the tinplate by a roller coater to form a uniform, thickness-controllable coating prior to cutting the tinplate into a can body blank. The coating machine can be independently coated by its own feeding device, or it can be combined with the printing machine to form a printing line.
The rotating stainless steel feed roller is half immersed in the feed tray, and the brought paint is transferred to the blanket cylinder through the screed roll. There is an impression cylinder under the blanket cylinder with a tooth decay device. When the tinplate is running to the blanket cylinder, the impression cylinder is licked at one end of the iron sheet, and the blanket cylinder and the impression cylinder cooperate to push the tinplate to pass, and the printing operation is completed. The thickness of the coating is controlled by the feed roller, the screed roll, and the gap between the blanket cylinder and the impression cylinder. Due to the spacing between the sheet metal and the sheet, a small amount of paint is carried away by the impression cylinder. The impression cylinder is scraped off with a spatula (to avoid the backside coating of the iron coating), and the scraped paint flows into the receiving tray, which is collected and returned to the storage tank through the conduit and recycled.galvanized steel pipe supplier
The side seam welding part of the can container can not be painted with paint, otherwise the body blank can easily break through the seam during the high-frequency resistance welding process and cause the waste can. Therefore, the operator needs to groove the blanket cylinder according to the printing area of the can container. The paint is grooved on the tinplate by the rubber drum, and the blank iron left in the slotted part is the high-frequency resistance welding part of the empty can.
The tinplate after printing is transported to the drying room by the conveyor belt, and is solidified by the oven at a high temperature by the circulating chain. The drying room is generally divided into three parts: the first part is to preheat the iron sheet to the baking temperature; the second part is the constant temperature baking; the third part is to make the iron sheet sufficiently cooled. The entire baking time takes 10 to 15 minutes. After that, the iron sheet was removed by an automatic unloading machine, and the coating was transferred to the can making process after passing the inspection, physical and chemical testing.4×4 square tubing