Offset printing is the main method of printing on metal cans because it is hard and does not absorb materials. The printing method can be divided into two types according to the tank structure. Sheet metal printing using lithographic plates is suitable for three sheet and DRD cans. In addition, surface printing using plastic relief plates (refer to two cans without horizontal plate printing) is suitable for two DWI cans and TULC.
Multiple identical images are coated on pre-processed metal plates and then transferred to a sheet press (rotary offset press) one by one for printing. A production line that is independent of the tank forming line.
The production process includes coating and printing. Coat the inner and outer surfaces of the plates (for example, tin plates about 0.2 mm thick) and large TFS (Wuxi steel) plates about 1 m long and wide, and then overprint each color on each plate.
The production process includes; Interior wall paint -& GT; Exterior wall paint -& GT; Print (many times) -& GT; Glazing oil - & gt; Baking and drying
Sizing (a transparent coating using a metal substrate to produce a metallic appearance) and a white coating to increase whiteness are used as a substrate. After printing, varnish is applied through a coating to protect the surface and provide gloss and smoothness.
(2) Surface printing
After the tank is formed, the surface of the two cans (DWI and TULC) is printed one by one using a curved press. Each color of ink is placed on a different (plastic relief) board and then sequentially transferred to a single blanket (the rubber surface transfers the inked image back to the tank) to print all colors at once. Varnish should be applied after printing and before the ink curing process.
The line control system automatically manages production consistency from tank forming to finishing (including printing and coating).
(3) Gravure printing lamination
A technique for laminating a preprinted PET film onto a forming tank using a gravure roller. Intaglio printing is a form of intaglio printing (the writing produced by pouring ink over engraved paper) that can be dried and overprinted by color and has the advantage of reproducing various color gradients (smooth shadows) and densities.
Multiple reproduction effects can be achieved, such as photo quality resolution, metal-like mirror appearance, and pearl-like appearance. The technology is also applied to laminate TULC.