Printing proof theing is not only inspection of the color separation film, but also pre quality analysis and assurance of the printing iron products. Its printing mode adopts the traditional offset printing printing mode. In the proofing process, it is necessary to keep color separation samples as the reference basis in the printing process control, so that the stable printing quality and color can truly reproduce the samples confirmed by customers. At the same time, since the printing iron is rarely a part of the final product, it is often a part of the processing process of various containers, lids and miscellaneous articles. At the same time, the proofing is used to test the processing performance and matching of the coating. Therefore, in this process, we need to process into finished products and put the contents in, that is, molding test. For example, food cans need to test the sealing, shelf life and freshness of the cans.