Analysis of the Quality Problem of the Hot Stamping of Electro-aluminum

(1) Hot stamping is not strong. There are many reasons why hot stamping is not strong, and there are differences in processing methods. In summary, there are mainly the following three kinds. 1 When the hot stamping temperature is low or the pressure is light, the hot stamping temperature and pressure can be readjusted. 2 In the printing process, due to the excessive dry oil added in the ink, the surface of the ink layer is dried too quickly to cause crystallization, so that the hot stamping foil is not hot stamped. The solution is sufficient, first of all to prevent the appearance of crystallization when printing, and secondly, after the crystallization is generated, the hot stamping foil can be taken off, and the printed product can be air-compressed under heating, and the light can damage the crystallization layer and then be heated. India. 3 Adding a proper amount of a wax-containing lighter, anti-sticking agent, or non-drying oily material to the ink can also result in poorly hot stamping. The solution is to first apply a layer of highly absorbent paper on the printing plate to press it once again. After the wax on the color ink layer is not adsorbed by the oil, the hot stamping operation is performed.

(2) The hot stamping image is faint and dizzy. During the hot stamping process, it was found that the picture and text were imaginary and dizzy. The main hot stamping temperature was too high, and the Aluminum Foil was coked. If the printing temperature of the printing plate is too high, so that the aluminum foil exceeds the limit that can be tolerated, at this time the hot stamping, the aluminum foil will be expanded around, resulting in fainting, hair false phenomenon, you must adjust the temperature according to the characteristics of the aluminum foil To the right range. For galvanized aluminum foil coking, the main reason is that the shutdown during the hot stamping process is too long, so that a certain part of the galvanized aluminum foil comes into contact with the electrothermal high-temperature printing plate for a period of time and the phenomenon of heat coking occurs, and the graphic and text will become dizzy after hot stamping. Therefore, in case of shutdown in the production process, the temperature should be reduced or the electro-aluminum foil should be removed. Alternatively, a thick paper can be placed in front of the higher-temperature plate to isolate the electro-aluminum foil from the plate.

(3) Handwriting is vague and pastes. The main reasons for this failure are the high stamping temperature, the excessive thickness of the electro-aluminum aluminizing layer, the excessive embossing force, and the looseness of the electro-aluminum installation. According to the specific circumstances to take appropriate measures to resolve. Excessive hot stamping temperature is the main cause of illegible writing and stencil. During the hot stamping of galvanized aluminum, if the printing plate temperature is too high, the film base layer and other film layers will be transferred and sticked, resulting in illegible writing and stencil. Hot stamping should be based on the temperature of the application of aluminum foil, the appropriate reduction in the stamping temperature. In addition, we should choose a thin aluminum aluminized layer, adjust the appropriate pressure, and properly adjust the pressure of the pressure roller and the winding roller tension.

(4) The edges of the graphic are uneven and unclear. The main manifestation is that when the galvanized stamp is stamped, the edge of the picture is edging, which affects the printing quality. The main reasons for this phenomenon are: uneven pressure in the printing plate, which is mainly due to the irregular layout of the plate, causing uneven pressure across the surface of the plate. Some pressure is too great, and some are too small. Uneven stress, the hot stamping, the surface of aluminum foil is not smooth, the adhesion of the various parts and the substrate is not the same, resulting in imprinting is not uniform. Therefore, the printing plate of the electro-foiled aluminum foil must be filled with a flat pad to ensure that the stamping pressure is even and the picture and text are clear. In addition, if the pressure of the printing plate is too large during hot stamping, it may cause the image printing to be uneven. During the hot stamping process, the hot stamping pressure must be adjusted to a suitable level. It is necessary to ensure that the pad of the embossing mechanism should be accurately fitted according to the area of ​​the pattern, without shifting or moving. In this way, it can be ensured that the graphic and pad overlays are matched during hot stamping and the hair around the graphic is avoided. Also, the pressure of the same plate after stamping is uneven. This is because the size of the graphic area is very different, and it is necessary to increase the pressure of the large-scale graphic text. The pressure of the size and area can be corrected and adjusted by the pad-sheet method to make it equal. Finally, if the temperature is too high during hot stamping, the image imprinting will be uneven. Therefore, according to the characteristics of the aluminum foil, reasonable control of the printing temperature of the printing plate, in order to ensure that the four sides of the picture is smooth, smooth, not hairy.

(5) Photographic prints are incomplete and lack of writing. This failure is mainly caused by the delivery of electro-aluminum foil, printing plates and other reasons. For example, the printing plate is damaged or deformed, which is one of the important reasons for the incompleteness of the graphic print. Therefore, if the plate is found to be damaged, the plate should be repaired or replaced immediately. The deformation of the printing plate does not allow the printing plate to withstand the applied stamping pressure, and the printing plate should be replaced and the pressure adjusted. If the electro-aluminum foil is cut and conveyed with deviations, when the electro-aluminum foil is cut horizontally when the edge is too small or the skew is applied, the cow will deviate when it is obliquely unwound, and the electro-aluminum foil will not coincide with the plate and graphic, and part of the picture will be exposed. Incomplete and incomplete. In order to prevent such problems, it should be neat and tidy when cutting electro-aluminum foil, and the margin size should be appropriately increased. Improper speed and tightness of the electro-aluminum foil can also cause such failure. Heart-shaped aluminum foil feeding and receiving device occurs - loose movement, or between the electro-aluminum foil core and the reel, the unwinding speed changes, the degree of tightness of the electro-aluminum foil changes, and the hot stamping position deviates, resulting in a figure Incomplete text. At this time to adjust the winding and unwinding device, but if the hot stamping foil is too tight, the pressure of the rewinding roller and the tension of the rewinding roller should be properly adjusted to ensure that the galvanized aluminum foil has a suitable speed and tightness. If hot stamping materials and hot stamping materials are not suitable or if excessive dusting during printing may cause such failures, adjustments should be made. In addition, the position of the printing plate at the bottom plate moves, drops, and the pad of the embossing mechanism shifts, so that the normal hot stamping pressure changes, and unevenness results in the incompleteness of the graphic imprint, such as light pressure. , can increase the pressure. Therefore, in the electro-aluminum hot stamping process, the apricot stamping quality should always be checked, quality problems should be immediately analyzed, and the plates and underlays should be inspected. Found that the printing plate moves or the pad shifts, adjusts in time, puts the printing plate and the padding back in place to fix.

(6) Hot stamping or texting. During hot stamping, there is a lack of printed flowers or hot stamping at the end of the picture. The main reasons are: 1 The hot stamping temperature is too low. The hot stamping temperature of the printing plate is too low for the electroformed aluminum foil to separate from the substrate and transfer to the substrate. The minimum required temperature, when hot stamping, the electro-aluminum foil is not completely transferred, resulting in the text flowers, exposed or hot stamping. When this quality problem is discovered, the temperature of the hot plate must be adjusted properly in time until it is printed. 2 Hot stamping pressure is small. During the hot stamping process, if the platen stamping pressure is too small and the pressure applied to the electrodeposited aluminum foil is too light, the galvanic aluminum foil cannot be transferred smoothly and the hot stamping graphic is incomplete. Found that this situation should first analyze whether it belongs to the stamping pressure is small, the outside observation of imprinted traces of the severity, if the stamping pressure is small should increase the stamping pressure. 3 The background color is excessively dry and the surface is crystallized. The underlying ink layer on the surface of the substrate is too thick and excessively dry, and crystallization will occur, so that the galvanized aluminum foil will not be hot stamped. When hot stamping, the dryness of the background color is printed immediately within the printable range. When the background color is printed, the ink layer should not be too thick. When the printing volume is large, it is necessary to print in batches, and the production cycle is appropriately shortened. Once the crystallization phenomenon is found, the printing should be stopped immediately, and the printing should be continued after searching for defects. 4 The type of galvanized aluminum foil is incorrect or of poor quality. When the type of galvanized aluminum foil is wrong or its quality is not good, it also causes problems in the quality of hot stamping. At this time, it should replace the type of aluminum foil with good quality, good adhesion and strong adhesion. Stamping larger area of ​​the substrate, can be hot stamping twice, you can avoid hair, exposed bottom and hot stamping is not on.

(7) Pattern stamping is dull. Most of this is because the hot stamping temperature is too high, and the temperature of the hot plate should be properly reduced. In addition, it is necessary to minimize the number of empty cars and reduce unnecessary parking because empty cars and parking will increase the temperature of the hot plate.

(8) The stamping quality is unstable. The same kind of material is mainly used, but the quality of hot stamping is good or bad. The main reasons are unstable material quality, temperature control of the hot plate, or loose pressure adjustment nut. The material can be replaced first. If the failure persists, it may be a problem of temperature or pressure. The temperature and pressure should be adjusted and controlled one by one.

(9) Leakage after hot stamping. The main reason is that the pattern of the object to be heated is too deep and the pattern of the object to be heated is replaced. When the pressure is too low and the temperature is too low, the pressure can be increased and the temperature can be increased.

In a word, there are many hot stamping faults in the aluminum foil. In addition to the hot stamping temperature and pressure speed, we must also pay attention to the printing materials or the replacement of the aluminum foil. We must carefully analyze them in order to solve the problem and eliminate the faults. .

(Text/Lin Qishui)