The hot stamping process is a special printing process that does not use ink. The so-called hot stamping refers to the process of hot stamping electrochemical aluminum foil onto the surface of the substrate under a certain temperature and pressure. The hot stamp machine is the equipment that completes the hot stamping process. Correct and efficient operation of equipment can bring greater benefits to our work. So, how to use hot foil stamping machine? Now, as one of the leading hot stamping machine suppliers, TRODISS will briefly introduce you to the operation process of the hot stamping machine:
Hot foil stamping machine mainly uses the principle of hot pressure transfer. Under the action of combined pressure, the anodized aluminum comes into contact with the hot stamping plate and the substrate. Due to the heating of the electric heating plate, the hot stamping plate has a certain amount of heat. The heating of the anodized aluminum melts the hot-melt dyeing resin layer and adhesive, and the dyeing resin layer has a strong adhesion. decreases, and the viscosity of the special heat-sensitive adhesive increases after melting. The aluminum layer and the anodized aluminum base film are peeled off and transferred to the substrate at the same time. As the pressure is removed, the adhesive cools and solidifies rapidly, and the aluminum layer is firmly attached to the substrate. Complete a hot stamping process.
There are two methods of electrochemical aluminum hot stamping: press hot stamping and rolling hot stamping. No matter which method is used, the operation process generally includes the following contents: preparation before hot stamping → plate mounting → pad → determination of hot stamping process parameters → trial hot stamping → sample signing → formal hot stamping.
Preparation work before hot stamping. There are two tasks of preparing hot stamping materials and hot stamping plates.
(1) Preparation of hot materials
Including the selection of anodized aluminum models and cutting materials according to specifications. Different models have different performance and suitable materials and ranges for ironing, such as white paper and prints with ink layers, solid prints and dot prints, large fonts and small fonts, etc. The choice of anodized aluminum models must be different. . For example, when the hot stamping area is large, you should choose anodized aluminum that is easy to transfer; for hot stamping small text or patterns, you can choose an anodized aluminum that is not easy to transfer; for hot stamping general graphics and text, you should choose a general-purpose anodized aluminum, etc. Before use, the large roll of anodized aluminum material must be cut into required specifications according to the area to be hot stamped. It is necessary to leave a certain margin when cutting, and to avoid wasting raw materials. Accurate calculations must be made in advance.
(2) Preparation of hot stamping plate
The plate material used for hot stamping is copper plate, which is characterized by good heat transfer performance, pressure resistance, wear resistance and no deformation. When the hot stamping quantity is small, zinc plates can also be used. Copper and zinc plates require the use of thick plates of 1 or 5 mm, which are processed into relief plates through photographic plate making. The corrosion depth of graphics and text should generally reach 0.5 to 0.6 mm. During processing, the corrosion should be slightly deeper, and the height difference between the image and text and the blank part should be as large as possible, so as to reduce the occurrence of continuous pieces and paste during hot stamping and ensure the quality of hot stamping.
It is to stick the prepared copper or zinc plate on the automatic hot stamping machine, and adjust the rules and pressure to the appropriate position. The printing plate should be pasted and fixed on the bottom plate of the machine. The bottom plate is heated by the electric heating plate and transfers the heat to the printing plate for hot stamping. The reasonable position of the printing plate should be the center of the electric heating plate. Because the center position is heated evenly, it should also be convenient for hot stamping operations. The method of fixing the printing plate is: cut the kraft paper or whiteboard paper with a quantitative value of 130 ~ 1809/m2 into an area slightly larger than the printing plate, evenly apply kraft glue or other adhesives, paste the printing plate, and then connect it. Turn on the power and heat the electric hot plate to 80~90°C. Close the printing plate and fully press the printing plate for about 15 minutes. The printing plate should be firmly stuck to the bottom plate flatly.
After the printing plate is fixed, the local unevenness can be adjusted to make the pressure uniform everywhere. The flat hot stamping machine should first level the printing plate, then paste a piece of coated paper of more than 100g/m2 on the back of the plate, and press it with copy paper to get the printed sample. Adjust the plate pressure according to the weight of the printed sample until the printed sample is printed. Clear and even pressure. Some moderately soft and hard pads can be pasted on the flat plate according to the hot stamping situation. Basically the same, but the thickness of the liner must be mastered to avoid deformation of the imprint; at the same time, the softness and hardness of the liner must be mastered to adapt to the needs of hot stamping on different printed matter. The purpose of using a liner is to make the printed matter have good elastic contact with the printing plate surface, thereby improving the quality of electrochemical aluminum hot stamping.
Determination of hot stamping process parameters
Correctly determining process parameters is the key to obtaining ideal hot stamping results. The process parameters of hot stamping mainly include: hot stamping temperature, hot stamping pressure and hot stamping speed. The ideal hot stamping effect is the comprehensive effect of these three. When the anodized aluminum glue layer is melted at a certain temperature, hot stamping must be achieved with the help of a certain pressure. At the same time, appropriate imprinting time, that is, hot stamping speed, is required to achieve firmness between the anodized aluminum and the printed matter. bonding.
(1) Determination of temperature.
The impact of hot stamping temperature on hot stamping quality is very obvious. If the temperature is too low, the isolation layer and adhesive layer of the anodized aluminum will not melt enough, which will cause the hot stamping wood or the hot stamping to be weak, causing the imprint to be incomplete and blooming. The hot stamping temperature must not be lower than the temperature resistance range of anodized aluminum. The lower limit of this range is the temperature that ensures the melting of the anodized aluminum adhesive layer. If the temperature is too high, the hot-melt film will melt out of range. As a result, the anodized aluminum is also attached around the imprint to produce a paste; it can also cause the synthetic resin and dye in the anodized aluminum dyeing layer to oxidize and polymerize, causing the anodized aluminum imprint to bubble or appear cloudy; high temperatures can also cause the aluminized layer and dyeing of the anodized aluminum The surface of the hot stamping layer is oxidized, causing the hot stamping product to lose its metallic luster and reduce its brightness. Factors that should be considered to determine the optimal hot stamping temperature include the model and performance of anodized aluminum, hot stamping pressure, hot stamping speed, hot stamping area, the structure of hot stamping graphics and text, and the color, thickness, and area of the base ink layer of the printed matter And the room temperature of the hot stamping workshop. When the hot stamping pressure is small, the hot stamping foil machine is fast, the background ink layer of the printed matter is thick, and the room temperature in the workshop is low, the hot stamping temperature should be appropriately increased. The general range of hot stamping temperature is 70~180℃. After the optimal temperature is determined, it should be kept as constant as possible from beginning to end to ensure stable quality of the same batch of products. When there are different graphic and text structures on the same page, choosing the same hot stamping temperature often cannot meet the requirements at the same time. There are two solutions to this situation: one is to choose two different types of anodized aluminum at the same temperature; the other is to use two electric heating plates if the layout allows (such as the distance between the two pictures and text is large) , controlled by two voltage-regulating transformers to obtain two different temperatures to meet the needs of hot stamping.
(2) Determination of pressure.
The function of applying pressure is to ensure that the anodized aluminum can adhere to the substrate, and to cut the hot stamping part of the anodized aluminum. The hot stamping process itself is a process that uses temperature and pressure to quickly peel off the anodized aluminum from the base film and transfer it to the substrate.
There are three forces in the entire hot stamping process; one is the peeling force generated when the anodized aluminum is peeled off from the base film layer; the other is the adhesive force between the anodized aluminum and the substrate; the third is the substrate (such as printed matter) Ink layer, white paper) surface adhesion. Therefore, the hot stamping pressure is higher than that of general printing. If the hot stamping pressure is too small, the anodized aluminum will not adhere to the substrate. At the same time, the edges of the hot stamping will not be fully sheared, resulting in the hot stamping not being able to go on or the hot stamping area becoming blurry. If the pressure is too high, the compression deformation of the liner and substrate will increase, resulting in paste or thickening of the imprint. When setting the hot stamping pressure, the hot stamping temperature, machine speed, the properties of the anodized aluminum itself, the surface condition of the object to be stamped (such as the thickness of the printed ink layer, the amount of white ink added during printing, the smoothness of the paper, etc.) should be comprehensively considered and other influencing factors. Generally, when the hot stamping temperature is low, the hot stamping speed is fast, the ink layer on the surface of the printed matter is thick, and the paper smoothness is low, the hot stamping pressure should be increased, and vice versa.
(3) Determination of hot stamping speed.
The hot stamping speed determines the contact time between the anodized aluminum and the substrate. The contact time is directly proportional to the hot stamping fastness under certain conditions. The hot stamping speed is slightly slower, which can make the anodized aluminum and the substrate be firmly bonded, which is beneficial to hot stamping. When the machine speed increases and the hot stamping speed is too fast, the hot-melt film and peeling layer of the anodized aluminum have not melted or melted insufficiently in an instant, causing the hot stamping to fail or the imprint to bloom. The printing speed must be adapted to the pressure and temperature. Too fast and too diffuse will have disadvantages. The general order of determining the above three process parameters is: based on the characteristics of the object to be ironed and the suitability of the anodized aluminum, the temperature and pressure are determined based on the printing plate area and stamping speed; both temperature and pressure must first determine the optimal Pressure to make the plate pressure moderate and evenly distributed; on this basis, the optimal temperature is finally determined. From the perspective of hot stamping effect, it is ideal to hot stamp with flatter pressure, lower temperature and slightly slower speed.
Trial hot stamping, sample signing and formal hot stamping
After the hot stamping process parameters are determined, the printing rules can be positioned. Hot stamping rules are also determined based on the printing sample. The flat-press hot stamping machine sticks a positioning block on the printing plate. The positioning block must be made of more wear-resistant metal materials, such as copper blocks, iron blocks, etc., and then try hot stamping on several sheets. The hot stamping quality meets the specified requirements and is tested. After the sample is signed, formal hot stamping can be carried out.
The above is the operation process of hot stamp machine. Have you learned how to use it? If you still have questions about hot stamp machine, please contact TRODISS to provide you with product solutions.