Self adhesive and bar code anti-counterfeiting
(5) hot stamping anodized aluminum. The bronzing of self-adhesive film material is completed in the form of a drum on the label machine at the same time as the printing process. On the flexographic label machine, the bronzing part adopts the rotary round pressing and bronzing method
① surface treatment of self-adhesive film. Bronzing is divided into two parts, one is bronzing directly on the film, and the other is bronzing on the ink layer. In order to prevent the ink layer or gold foil from falling off, the film must be corona treated first to make its surface tension reach 38 × N (38dyn) or more
② treatment of ink layer before bronzing. UV ink is the most commonly used in film printing. There are usually two kinds of failures when bronzing on the UV ink layer. One is that the ink surface cannot be hot stamped. The reason is that the surface tension of UV ink is low, or the quality of hot foil is poor, and the viscosity is not enough. The solution is to apply Special polish on the ink layer and polish it locally first to improve the surface tension of the ink layer; Or use hot foil with high viscosity. The second is that after bronzing, the gold foil is removed together with the ink. The reason is that the ink layer is too thick or the ink layer is not dry. The solution is to control the ink thickness during printing, and deep ink thin printing method can be used, that is, when mixing ink, the ink color should be slightly deeper than the sample; You can also print two layers of thin ink to ensure the color and density of the ink
③ selection of bronzing foil. Be sure to choose bronzing foil for film, and choose the appropriate variety according to the specific situation of bronzing pictures and texts
④ technician for making bronzing plate. The bronzing effect is directly related to the quality of the bronzing plate. The bronzing plate should be corroded deeper as far as possible to increase the height difference between the text and the blank part. SMM news: June 6, to prevent dirt; The corrosion between small words or patterns should be clear and clean, otherwise the small blank will be discharged unclearly during hot stamping, which will affect the quality. The surface of the bronzing plate is not smooth, and collision is avoided. When the bronzing area is large
, the variable duplex processing is single processing to reduce the processing area and ensure that the layout is flat and heated evenly
⑤ selection of hot stamping plate liner. The liner of hot stamping plate should be flat. For large-area on-the-spot hot stamping plates, medium hard liners are generally used, and hard liners should be used for hot stamping plates mainly composed of words and patterns. When bronzing
, always check and adjust the lining. If there is indentation deformation, replace the gasket immediately to ensure the consistency of hot stamping quality of batch products
⑥ adjustment of hot stamping temperature, pressure and speed. Different varieties of hot stamping foil have different applicable temperature ranges. Usually, the printing factory adjusts the temperature and pressure at a fixed machine speed
temperature control should ensure that the hot melt adhesive on the hot stamping foil is completely melted, and the aluminum foil is firmly adhered to the film without discoloration
the standard of pressure control is to carry out surface treatment before hot stamping and filling, with clear graphics and texts, no luminescence, no deformation, smooth waste discharge and no residue
(6) die cutting. The die cutting of film materials is different from that of paper. First, the film must be cut thoroughly to discharge the waste, while the paper can discharge the matured waste at room temperature under the condition of basic cutting. The film has high hardness and toughness, which requires the die
cutter to have high strength, so the blade is generally single edge, with an angle of 21o, while the paper die cutter is double-edged 28O
(7) waste discharge. Due to the high strength of the film, there is basically no fracture problem, and it is relatively easy to discharge waste, but the die cutting is not transparent, which is easy to peel off the labels when discharging waste
the arrangement of labels is very important, because waste discharge is closely related to the arrangement of icons. The labels are arranged horizontally in multiple ways, and staggered arrangement should be adopted as far as possible, so as to make the collection of waste more convenient
at the same time, in this way, only one horizontal blade is working at each time, rather than all the die-cutting blades, which can greatly reduce the working pressure of the die-cutting tool (Fig. a). This is particularly important when die cutting
thick paper (such as tag labels)
the arrangement of labels, the calibration of the force measuring lever, and the actual state of the tensile testing machine are also very important, as shown in Figure 1, because the waste collection is closely related to the arrangement direction of the icons. The recessed part or opening part on the icon should be placed on the paper output side, otherwise, it is easy to tear
or even tear, as shown in Figure B
a b
arrangement of icon labels
source: Jiangnan University
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