Rich and elegant emboss process

Embossing is an important process in the packaging and post-printing process. It is an imprinting method that does not use printing ink. During the embossing process, a set of concave and convex stencils corresponding to yin and yang are used to place the substrate between them, and the embossed embossed graphics are pressed by applying a large pressure. This method is mostly used for the post-press processing of printed materials and paper containers, such as the decoration of trademarks, cigarette packets, paper boxes, New Year cards, bottle labels, etc., so as to achieve a vivid and beautiful three-dimensional feeling. The use of proper embossing technology can increase the sense of layering of the printed pattern and play a crucial role in the packaging product.

At present, many domestic packaging and printing companies are equipped with high-speed flat sheet-fed high-speed automatic die cutting machines. However, due to the lack of suitable stencils in embossing, they often give rise to slow-moving, low-efficiency manual die-cutting machines. Bronzing machine. The reason is that the conventional embossing stencil cannot be fixed on the high-speed automatic die-cutting machine. Even if the honeycomb stencil is installed or the stencil plate is fixed to fix the concave stencil, it is difficult to adjust the partial pressure, resulting in difficulties in use.

Pressing template

Compression stencils are a pair of masculine and masculine counterparts for images and text, including a concave stencil and a convex stencil.

First, make concave template

Convex stencils used for embossing are generally made of copper or steel plates. The plate making process is etched and then sculpted.

After the copper plate or steel plate is corroded, because the depth of the depressions on the plate surface is the same, the outline is not obvious, the layer is lacking, and the mouth of the plate is rough. Therefore, it must be processed through engraving to make the concave convex plate.

Engraving processing is a detailed modeling process. Different methods are used to sculpt according to the type of pattern. If the picture is circular, the edition will be rounded; if it is a character and a line, it will be trimmed into a straight edge; if you want to highlight the three-dimensional shape, you can make the version of the bevel. The production quality of the concave template is the key to determine the quality of the printed convexity.

Second, the system of convex template

After the embossing stencil is made, it must also be equipped with a convex stencil opposite to the stencil.

1. Traditional plaster convex stencil making process

The traditional plaster stencil making method is as follows: the prepared copper (steel) concave stencil is pasted and fixed on the metal bottom plate of the flat press machine, and leveled; meanwhile, the yellow cardboard is pasted on the stencil plate and the glue or the glue is used. The plaster paste of glutinous rice paste was quickly coated on a yellow paper-bonded plate. After a little flattening, a thin layer of paper was applied. In order to prevent gypsum powder from falling into the pattern, it is necessary to cover it with a layer of plastic film and gently brush a layer of kerosene on the negative stencil before embossing to prevent sticking of the plaster mold during embossing.

When pressing the plaster mold, the first embossing force should be small, showing a slight shadow; when the second embossing, a thicker whiteboard paper should be added behind the concave stencil until the gypsum powder is dried quickly. Pressure. After the gypsum powder is completely solidified and dried, the excess gypsum is removed and a gypsum embossed convex stencil is made.

2. New PVC prefabricated convex stencil process

Because the traditional gypsum copying stencil process is complex and time-consuming, the stencil must be prepared first, and then copied on the spot on the embossing machine to reduce the speed, and the plaster strength is low, and the imprinting continues. The degree of gypsum's collapse due to extrusion increased. For these reasons, it is imperative to seek a new material that has good mechanical strength and rapid and convenient molding. After comparing various properties of various thermoplastics such as viscous flow temperature, elastic modulus, toughness, and adhesive strength of rubber-based adhesives, it is considered that both polyvinyl chloride and polystyrene are ideal, but due to the They are crisp and inconvenient to cut, so they chose PVC. This material is richer and more affordable than polystyrene. The production process consists of arranging the polyvinyl chloride plate and the mold into a molding press with a heating and cooling system, and adjusting the temperature and pressure to obtain the product with the same shape as the mold and having the same concavity and convexity. Its production steps are:

(1) Surface cleaning. The surface of the cut polyvinyl chloride board is cleaned to remove the hair spots and oil stains, and the concave stencil and the mold frame are also cleaned. Detergents or weak acid (base) solutions are generally used.

(2) Apply release agent. Apply a mold release agent to the contact surface of the stencil plate and polyvinyl chloride plate. Commonly used mold release agents are silicone grease, silicone oil and a mixture of both.

(3) Pack the machine. The concave stencil plate and polyvinyl chloride plate were placed in a mold frame, covered with a cover plate, and fed into a mold press. Note that there should be an appropriate gap between the reticle and the wall of the frame to allow the excess melt to flow out.

(4) warming and pressurizing. The pressure is appropriately pressurized before the temperature is raised so that the object to be pressed is closely contacted, and the pressure is applied after reaching a predetermined temperature value. The pressure should be based on the size of the layout, the depth of the text, and the thickness of the line. Usually 100 ~ 300kgf/cm2.

(5) cooling demoulding. When the temperature is cooled to room temperature, the pressure is released and the mold is released.

(6) Cutting inspection. After trimming the corners other than the graphic, it is completed without defects.

The fixing method of new PVC prefabricated convex stencils is:

(1) Fix the negative stencil with double-sided adhesive on the aluminum plate, and position the aluminum plate on the hot plate with screws. Note: The graphic center of gravity of the concave template should be on the central axis of the hot plate in order to equalize the pressure.

(2) Paste the double-sided tape on the back of the PVC stencil.

(3) Put the PVC convex stencil on the concave stencil and fix the four corners with glass glue.

(4) Propagation of the male template. Switch on the plate and turn on the PVC under pressure to fix the plate on the plate with double-sided tape.

Die cutting embossing one-time die cutter

Die-cut embossing One-step molding die manufacturing technology is based on the laser knife mold manufacturing technology to improve and innovate. Therefore, the precision of die-cutting and embossing one-step molding die cutting is indisputable. The concave-convex stencil that the die is equipped with is a male and female die (because the front side is convex and convex, the female die is an inverted stencil, and the male die is a positive stencil). If the die-cut product has an indentation line, it must be equipped with a special indentation bottom touch. (If the crease of the packaged product is a toothed wire or a half-threaded wire, then no bottom mold is required. The following molds are all marked with an indentation. For example). These materials are carefully designed, precision-machined, and cleverly combined with each other in the course of use, so that the die-cutting and embossing of the one-time die cutter can be achieved by one-time compression molding.

In the production process of die-cut embossing one-step die cutting, the customer must first provide accurate die-cutting pressure convex film and die-cutting drawings. Afterwards, according to the information provided by the film and drawing, a precise laser cutting machine is used to define the holes for installing the steel knife and the copper wire on the plate material, and the window for installing the male stencil plate and the female stencil plate is defined. These windows must not only avoid the knife and thread on the die, but also have a one-to-one correspondence with the positions of the pressed graphics. After the work to be loaded is completed, an aluminum concave stencil pad is set in the window reserved by the dies. There are wire pins on the four sides of the aluminum backing plate so that the backing plate can only be set in from the back of the die and cannot be removed from the front. This is very important. The purpose is to prevent accidental release of the pad from the die when the die cutter is working. Several positioning screws are installed on the edges of the concave stencil, which can fix the stencil plate on the aluminum pad so that the concave stencil is integrated with the cutter die. Loosen the set screw. The reticle can be freely adjusted on the die. It should be noted that the sum of the thickness of the aluminum backing plate and the thickness of the concave stencil and the thickness of the bottom of the convex stencil should not be greater than the height of the steel wire on the die. With such a condition, press-bump die-cutting one-step molding die can complete the press-blanking die-cutting molding of a printed product.

In the process of pressing and punching die cutting one time, after the cutter plate is clamped, the steel knife and the steel wire fixed on the die position of the film can be cut by the concave and convex die plate, and then the movable concave die plate can be used to adjust the position. The concave template graphic corresponds to the graphic and text on the embossed film. In this way, the relative positions of the knife and the wire on the concave stencil and the knife die are set. That is, the positions of the knife, the wire, and the concave stencil on the knife die are aligned with the position of the graphic and text on the print sheet. After the adjustment of the die can be set on the rules. After the die-cutting rules are registered, the die is pulled out, and the indentation bottom die is fixed on the die die with the bottom die positioning pin, and the self-adhesive oiled paper on the back side of the bottom die is peeled off, and then the die cutter and the locking clip are pushed. Once the air pressure is applied at an appropriate pressure, the indentation bottom mold is stuck on the die-cutting machine.

Like the knife touch, the indentation bottom mold is also provided with a window corresponding to the punching stencil one by one. The purpose of this is to facilitate fixing the punching stencil of the punching stencil to be installed. In the installation of the convex stencil, the cutter die must be removed from the die-cutting machine again, and the convex stencils coated with the strong glue on the back are fixed on the corresponding concave stencils (the convex stencil without the positioning pins). The butter can be glued onto the stencil. After all the male phantom plates have been loaded, the die plate is loaded and the air pressure is once again activated, and the convex phantom plate is accurately placed in the reserved window.

The next thing to do is to adjust the overall pressure, local back pressure regulation, and other work that is basically the same as the previous die-cutting operation. If it is found that the individual embossing stencils are misprinted, you can remove the embossing stencil from the plate and reposition the embossed stencil. After the alignment, insert the male stencil back onto the iron plate until full registration.

From the above description of the production and application of die-cut embossing one-step die cutter, it can be seen that the die-cut embossing one-step die cutter is not only fully suitable for high-speed automatic die-cutting machine, but also has the advantages of convenient operation and reduced time-consuming and time-consuming adjustment. You can also complete the post-press finishing that was completed in two processes at a time, which is more efficient. If the packaging products you produce need to be embossed and die-cut, once you use the die-cut die-cut die-cutting die, you will not have the strange phenomenon that the high-speed automatic die-cutting machine will wait for the manual die-cutting machine. In the workshop, there are piles of pending semi-finished products.