1. Failure phenomenon: hot stamping is not strong
Main reasons and solutions: There are many reasons why hot stamping is not strong, and there are differences in processing methods. To sum up, it is mainly related to factors such as stamping temperature and pressure, ink formulation, surface characteristics of printed parts, properties of anodized aluminum, and so on. 1 When the hot stamping temperature is low or the pressure is light, the hot stamping temperature and pressure can be readjusted. Due to the difference in equipment, hot stamping materials, hot pressing time and hot stamping temperature are all different. For example, a high-speed circular press has a fast speed and the embossing line contacts. The hot stamping temperature is higher than that of a round press or a flat press. Under normal circumstances, round hot stamping temperature of about 190 °C ~ 220 °C, round flattening about 130 °C ~ 150 °C, flattening about 100 °C: ~ 120 °C. In addition, hot pressing time, hot stamping temperature and production efficiency are also largely constrained by the transferability of the electro-aluminum. 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 to prevent crystallization from occurring as much as possible during printing. Secondly, after the crystallization is completed, the stamping foil can be removed. After the heating, the printed product is air-compressed and the crystallized layer is destroyed first. India. 3 Adding proper amount of wax-containing retreating agent, anti-sticking agent, or non-drying oily substance to the ink may also result in poor hot stamping. The solution is to first apply a layer of highly absorbent paper on the printing plate to press it once again, adsorb the wax and non-drying oil on the ink layer, and then perform the hot stamping operation. 4 Too much dust on the surface of the print or the surface contains additives such as releasant and bright light, which hinders the adsorption of the aluminum foil and the paper. The solution is to remove the powder on the surface or to solve it in the printing process. 5 The improper use of anodized aluminum directly affects the fastness of hot stamping. According to the size of the bronzing area, the characteristics of the stamped material should be considered in consideration of what type of galvanized aluminum is selected. According to the practical experience of some manufacturers, when electrified aluminum is used for ordinary products, hot stamping (generally black) can be used with type 88-1, KURZ PM; cigarettes, cosmetics and other dark ink prints (including printing gold, printing silver) gold foil Select Type 88-2; cigarettes, cosmetic packaging and other fine handwriting stamping of electro-aluminum are 88-3, 88-4, PM288, etc.; suitable for OPP or PET overlay paper and UV ink cardboard, coating Paper and other products stamped with electro-aluminum are 88-4 type, K series, LK series, and SP series.
2. Failure phenomenon: pull back
The main reason and solution: In laminated hot stamping, anodized aluminum sticks down the printing ink or the varnish. The main causes of this failure are the following aspects. 1 The main reason is that the ink on the surface of the printed product is not dry or the post-processing of the surface of the printed matter such as UV varnish is improperly processed, which causes the surface ink, UV varnish, and the paper surface of the printed product to be loosely bonded. The adhesive force cannot withstand the adhesive force of the electro-aluminum foil layer and Peel force at separation. Solution: After the prints are dried and then hot gold. Can use fast-drying ink or add a proper amount of desiccant in the ink to ensure that the ink drying speed can be suitable for hot stamping requirements. Prolong the hot stamping time or use drying rack to dry and then hot stamping. In addition, anodized aluminum with low electro-aluminum separation and excellent heat transfer properties can be used. 2 When printing, the pressure is insufficient or the pad is even, so that the printing ink layer is too thick, and the ink does not penetrate into the fibrous structure of the paper and it floats on the surface of the paper. This requires the printing pressure to be controlled during printing. For the letterpress printing products, the plate printing requirements should be flat and uniform, and the bottom tray should be made of metal material to ensure that the printing pressure is solid, uniform and sufficient. 3 The viscosity of the ink itself is too low and less than that of the electro-aluminum foil layer. Pay attention to the use of fast-fixing inks that meet the requirements for viscosity printing. Pay attention to controlling the amount of anti-sticking agent added in the ink and ensuring that the viscosity of the ink meets the requirements. 4 When light-colored inks are formulated, inks with coarse pigment particles (such as white ink, etc.) are used. The binding force between the ink and the binder is poor, and the binder in the ink is easily absorbed by the paper after printing. The pigments are suspended on the surface of the paper and cause chalking. It is very easy to cause the disadvantages of discoloration. In this way, the layer of electro-aluminum foil cannot be peeled off successfully during stamping, but the ink layer on the print will be pulled back. Therefore, it is necessary to dilute the use of titanium white ink as little as possible or use a mixture of a light diffusing agent and white ink. In addition, when designing, it should be fully considered to avoid large-area hot stamping on a light-colored ink plate surface. In addition, for the phenomenon of chalking in the ink layer of the printed product, and the phenomenon of reverse pulling caused by excessive white ink, some measures can be taken to remedy it, such as using 991 No. light diffusing agent and appropriate amount of white dry oil for deployment. Stamping the plate once and then hot stamping can also improve the hot stamping effect.
3. Failure phenomenon: exposed
Main reasons and solutions: During the hot stamping process, the graphic or text will not appear on the bottom or the hot stamping is not possible. The main reasons are as follows: 1 The stamping temperature is too low, and the hot stamping temperature is too low for the electroformed aluminum foil to break away from the film base and transfer. To the minimum temperature required on the substrate, the electro-aluminum foil was not completely transferred during hot stamping, which resulted in the failure of the graphic text, the exposed bottom, or the 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 hot stamping pressure, and observe the severity of imprint marks, such as the hot stamping pressure is small, the stamping pressure should be increased. 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.
4. Symptoms: flowers and flowers
Main reasons and solutions: There are many reasons for this failure. For example, the pressure of stamping is not enough, the force is not even, etc., and it is not enough to completely peel off the affixed aluminum foil and adhere to the printed product. Attention should be paid to adjusting the control pressure and ensuring the printing. The plate is flat; the temperature is too low, so that the adhesive layer of the aluminum foil is not melted or is not uniform, and a suitable stamping temperature is to be pre-tested; the hot stamping speed is too fast, so that the foil separation force and peel force of the aluminum foil do not match. , to adjust the hot stamping speed; lining is not smooth or too soft, so that the location of the pressure of the stamping foil is not complete separation of electroformed aluminum foil, we must pay attention to check the quality of the liner, replace the liner and its liner material, so that the liner is good The degree of flatness; the use of the type of aluminum foil is not consistent or poor quality, so that the foil layer is difficult to completely peel and transfer, should replace the appropriate quality of the good quality of aluminum.
5. Symptoms: the picture is made of virtual, faint
Main reasons and solutions: In the process of hot stamping, it was found that the failure of the picture and text and fainting was mainly caused by the high stamping temperature and the coking aluminum foil. 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.
6. Failure phenomenon: paste version
Main reasons and solutions: This is one of the more prominent issues in foil stamping. The main reasons for this failure are the high printing temperature of bronzing, the excessive thickness of galvanized aluminum plating layer, the excessive force of embossing, the looseness of the installation of galvanized aluminum, the incorrect foiling of galvanized aluminum, and the poor production of bronzing plates. According to the specific circumstances to take appropriate measures to resolve. Excessive hot stamping temperature is the main cause of unclear writing and stencil. During the hot stamping of galvanized aluminum, if the printing plate temperature is too high, melting occurs when the galvanized aluminum foil layer is separated, resulting in transfer and stickiness of the film base layer and other film layers. If the writing is unclear and the stencil is blurred, the hot stamping temperature should be appropriately adjusted according to the applicable range of the temperature of the galvanized aluminum foil, and the temperature increase caused by the long downtime in the hot stamping should be avoided as much as possible. In addition, there are obvious slopes on the edge of the printing plate or the plate is too thin, or the over-hot stamping of the printing plate wears down, so that the difference between the hot printing plate surface and the blank space is too small, the cushion material is too soft, and blank areas and electroplating of the plate are caused. For aluminum foil layer contact, etc., the edge of the plate shall be made to a right angle of nearly 90 degrees (if the engraving process is used for plate making, the edge of the plate will have almost no slope). According to the features of the hot plate surface, a thick plate of plate material is used. And the blank part of the corrosion deeper, using a hard lining for hot stamping; In addition, should choose a thin layer of aluminum electroplating aluminum, adjust the appropriate printing pressure, and adjust the pressure of the pressure roller and the winding drum tension.
7. Symptoms: the picture is not clear, the edge is not smooth
The main reason and solution: This fault is mainly manifested in the aluminum foil hot stamping, the edge of the graphics (flash) phenomenon, affecting the quality of printing. The main reasons for this phenomenon are: uneven pressure in the printing plate, which is mainly due to uneven layout during plate loading, causing uneven pressure on various areas of the plate, some pressure is too large, and some are too small, thus making the graphic Uneven stress, the surface of the stamping foil is not clean, the adhesion of the various parts and the substrate is not the same, resulting in uneven printing. Therefore, the printing plate of the electro-foiled aluminum foil must be flat and solid to ensure that the stamping pressure is even and the graphic image can be avoided. In addition, improper loading of the plate results in bowing or loosening of the plate; wear and looseness associated with the embossing mechanism; cushion material is too soft and deformed badly; the plate is too thin or the layout slope is too small and the like can cause this failure. Therefore, we must carefully observe and analyze, find out the reasons for the treatment of the right medicine, such as text, line layout and field version can be adjusted to lower the pressure, check the fixed version of the printing plate, eliminating the plate from the bow and loose Phenomenon: Check whether the embossing mechanism and other parts are tangled or loose during hot stamping. Repair and tighten the worn and loose parts. Replace the neutral hard material for the liner. Never dig on the liner. Empty or repeated affixing, according to the structural characteristics of hot stamping layout, choose a thickness one
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