Die Cutting Indentation Technology Overview (I)

I. Introduction

With the development of society and the improvement of people’s living standards, consumers, in addition to demanding the inherent quality of goods, have also put forward higher requirements for the packaging of goods, including the design of packaging and decoration of goods. It also includes requirements for the quality of packaging and post-press processing. Die-cut indentation is an important production process for post-press processing. It is suitable for the finishing of various types of printed materials. The quality of die-cutting directly affects the overall market image of the product. Therefore, the traditional die-cutting indentation technology and the new The development of die-cutting technology can effectively enhance the competitiveness of printing companies.

Molding technology is based on the model indentation and stencil cutting two kinds of processing technology, the integrated name, the principle is in the fixed mold, through the application of the size of the pressure, so that the printed carrier paper force part of the compression deformation or fracture separation. The main parts of die-cutting and indentation equipment (abbreviated as die-cutting machine) are die-cutting table and press-cutting mechanism. The processed sheet material is between the two, and die-cut finishing technology processing is performed under pressure. There are different types of die-cutting indentation presses and corresponding press-cutting mechanisms. The die-cutting machine is divided into three basic types: flat-pressing, round-pressing, and round-pressing. The flattening and die-cutting machine can be divided into two types: vertical and horizontal, due to the difference in orientation between platen and platen.

Second, flat pressure molding

The shape of the platen and the press-cutting mechanism of this type of press machine are flat-shaped. When the plane of the platen and the press plate is in the vertical position, it is a vertical flat-platen press, as shown in FIG. During work, the platen is fixed and the platen presses the platen to pressurize the platen. Different movement trajectories of the pressing plate can be divided into two types: one is that the pressing plate swings around the fixed hinge, so at the moment of starting the pressing, there is a certain inclination between the working face of the pressing plate and the stencil surface, so that the cutting plate is earlier Cut into the lower part of the cardboard, it is easy to cause the pressure in the lower part of the die plate and the upper part has not been cut through yet. In addition, the component force of the mold pressure P also causes lateral displacement of the cardboard.

Another kind of platen movement mechanism is shown in Figure 3. During operation, the pressure plate 4 is driven by the connecting rod 3, firstly using the cylindrical roller 8 as a fulcrum, swinging on the flat rail 9 of the base, and when the working surface of the pressure plate is tilted to a position parallel to the molded plate 5, Then press in parallel to the die-cut version in translation.

The vertical flat press molding press has the advantages of simple structure, convenient maintenance, easy to grasp its operation and replacement of die-cutting indentation plates, but the labor intensity is large, the production efficiency is low, and the number of work per minute is more than 20 to 30 times. In small batch production. Domestic vertical flat presses have MLB880 models.

The platen and platen working face of the horizontal flat pressing mold press are in a horizontal position. The lower platen is driven upward by the mechanism and pressed to the platen for die-cutting indentation.

Due to the small stroke of the horizontal press platen, it is difficult to insert or remove the paperboard manually. Therefore, it usually has an automatic feeding system. Its overall structure is similar to that of a sheet-fed offset press, and the entire machine is automatically input from the paperboard. System, molded part, cardboard output part, and electrical control, mechanical transmission and other parts. Some also have automatic stripping devices, as shown in Figure 4.

Among them, the paperboard input part 1 and the output part 4 are basically the same as the principle of a sheet-fed offset press. The molded part 2 is pressed by a toggle, camshaft or double toggle system. General pressure system does not have pressure progressive and pressure delay devices, pressuring time can be selected according to the need of molding process. The pressure adjustment is done by a specialized agency and can be adjusted at any time while the machine is running or at a standstill. In the figure, 3 is the part of the evacuation chip.

The horizontal flat-press die press is safe and reliable, its automation degree and production efficiency are relatively high, and it is an advanced model in the flat-press die press. Domestic models such as MQW860, MY820, etc.; abroad, there is a Swiss company BOBST SPl02 a BM type.

Third, round pressure molding

The round press molding press mainly consists of a planar plate table for reciprocating motion and a rotating cylindrical pressure roll. During the working stroke, the platen moves forward and the pressure roller presses against the cardboard and rotates at the same surface line speed as the platen to die-cut and indent the cardboard. When returning the stroke, the platen backs back and the working surface of the pressure roller does not come in contact with the die plate.

According to the different rotation conditions of the pressure roller in a working cycle, this kind of molding machine can be divided into stop rotation, one rotation, two rotation, etc. The positive and negative round pressure molding press is a simple type, and its positive and negative strokes are However, the work schedule.

Because the circular press molding machine adopts a cylindrical pressure roller instead of the pressure plate, it is no longer a "surface contact" but a "line contact" when it is die-cut, so that the pressure the machine is subjected to when molding is small, and the pressure is relatively small. Evenly distributed over a long period of time, the load of the vertical platen press plate movement mechanism of the machine frame 3 is relatively stable, and the large-format die cutting can be performed. However, due to the force component generated by the pressure roller and the platen, the knife blade edge is easily deformed or displaced. Fourth, circular pressure molding

The working part of both the platen and the press-cutting mechanism of the round press molding press is cylindrical. When it is in operation, the feed roll feeds the paper board between the press plate cylinder and the pressure roller, and clamps both of them. Molding when rolling, the mold platen rotation is a working cycle.

The die-cutting method of circular press molding machine is generally divided into hard-cut method and soft-cut method. The hard cutting method means that the die cutter is in rigid contact with the pressure roller surface during die cutting, and thus the die cutter is relatively easy to wear. The soft cutting method is to cover the surface of the pressure roller with a layer of engineering plastic. When the die is cut, the cutter can have a certain cutting amount. This can not only protect the cutter, but also ensure complete cutting, but the plastic layer needs to be replaced regularly.

Due to the continuous rotation of the drum during the operation of the round press molding press, its production efficiency is the highest in all types of presses. However, the die-cut version must be bent into a curved surface, the plate making and plate mounting are relatively troublesome, the cost is relatively high, and there is a certain degree of technical difficulty. Therefore, the round press molding machine is often used for mass production.

At present, most of the advanced die-cutting equipments are developed in the direction of automatic combination of printing and die-cutting. The molding mechanism and the printing press are connected into an automatic production line, and its structural forms are various. This production line consists of four main parts, namely the feed part, the printing part, the die-cut part, the delivery part and so on.

The feeding portion intermittently feeds the cardboard into the printing portion, and can be easily and accurately adjusted according to different material forms, sizes, types, and the like. The printing part can be composed of 4 to 8 color printing units, and can use different methods such as gravure, offset, flexo, and the like. This part has more advanced printing functions and is equipped with its own automatic drying system. The die-cut part can be a flat press die press or a round press die press, and both are equipped with a stripping device that can automatically eliminate corner scraps generated after die cutting. The conveying part is to collect and send out the finished product after the molding process, so as to ensure that the feeding part, the printing part and the die cutting part can smoothly realize the high-speed continuous operation. Figure 5 is an example of this type of press.

With the improvement of the technological level in recent years, the price of round press die cutting equipment has been significantly reduced. At present, it has a wide user base in China.

Fifth, roll paper molding

Roll paper cutting machine has a round pressure and flat pressure. Flat-press web-type die-cutting machine is a machine for die-cutting and indentation of web paper from paper roll, both wired and online. In the off-line processing method, a printing machine is used to print the reeled paperboard, and the reeled paperboard rewinded onto the reeling machine is placed on a die-cutting machine for a die-cutting indentation process. The off-line processing method is characterized by the fact that the printing press has no connection with the die-cutting creasing machine and is not restricted to each other. High-speed printing presses can use more than one die-cutting machine to cooperate with the printing press, or increase the boot time of the die-cutting creasing machine.

The in-line processing method is that a die-cutting machine is connected with a printing press to form a linkage machine, and a printing and die-cutting indentation process is used to start the production from the roll paperboard. This method can reduce the operator, but generally the speed of the printing press is higher, and the speed of the die-cutting creasing machine is lower. The speeds of the two cannot be matched. The speed of the printing press can only be reduced, and the speed of the die-cutting creasing machine cannot be increased. Productivity is affected.

Six, on-line molding

The so-called on-line die-cutting mainly refers to on-line flat die-cutting and on-line round die-cutting. On-line die-cutting has the advantage that sheet-fed die cutting can not match. Some experts predict that it will become the mainstream of die-cutting equipment market in the next few years. On-line die cutting is characterized by fast speed and high accuracy, which can greatly increase production efficiency, shorten production cycle and reduce production costs.

The highest level of on-line flat die cutting can reach more than 20,000 per hour, which is much higher than that of sheet-fed die cutting. Because the die-cutting plate used is the same as that used for sheet-fed flat die-cutting, the manufacturing process is simple and the cost is low. Currently, the die-cut version is widely used in the post-press processing of medium and long-sized package products, and the market prospect is generally promising.

Online circular die cutting is mainly applied to the single-line, high-volume post-press line. Its main feature is a series of operations such as hot stamping, compression molding, die cutting, and decantation of printed reelboards, so that the printed sheets are processed into the final product at one time. According to Professor Xu Wencai of Beijing Institute of Graphic Arts, the production rate and die-cutting precision of on-line circular press die cutting are generally higher than that of on-line flat die cutting. The current maximum speed can reach 180m/min, and the maximum speed of round press die cutting machines It can even reach 300-350m/min. Online circular die cutting avoids a series of quality problems caused by multi-pass printing, such as surface blemishes, inaccurate positioning of hot stamping, and high scrap rate. At the same time, it reduces equipment investment and floor space, saving a large number of operators. , shortened the production cycle. Although on-line circular die-cutting has some advantages that are not available in on-line flat die-cutting, due to the high cost of circular die-cutting tools and the complexity of die-cutting, the promotion and application in the country are greatly restricted. . At present, online circular die cutting is only used more and more abroad.