The overall process and knowledge of die-cutting and indentation
Die-cutting indentation is a special process in post-press processing, and it is mainly used according to the design requirements. This article mainly introduces the overall process flow of die-cutting indentation from the definition of die-cutting indentation, the printing plate of die-cutting indentation and the production process of die-cutting indentation.
What is die cutting indentation?
Die-cutting and indentation process is to make the edges of color prints into various shapes according to the requirements of the design, or to add a special artistic effect to the prints, and to achieve certain functions. The process of arranging a steel knife into a mold (or engraving a mold with a steel plate) and punching the substrate into a certain shape on a die-cutting machine is called a die-cutting process; using a steel wire to stamp or emboss on the substrate The process of leaving grooves conducive to bending is called indentation process.
What is a die-cut and indented printing plate?
The printing plate used for die-cutting is actually a steel wire with a front edge, the height of which is about 23.8mm. The steel wire is bent into various required shapes on the fixture, and then assembled into a "printing plate". After embossing, the substrate is cut into the required shape. The printing plate used for indentation is also a steel wire, the height is slightly lower than the knife line used for die cutting (about 0.8mm lower), and there is no sharp product. After the formation of the "printing plate", it is used for imprinting, so that marks appear on the surface of the substrate. Seamless knives with special requirements are made of a single piece of steel. This type of knives has a higher cost but is durable.
What kind of masters are there for die-cutting and embossing plates?
To make a die-cut and indented printing plate, you must first make the master, then bend the network cable according to the required knife shape, and arrange it in the master. The master has two types: metal and wood.
①Metal base plate. There are many types of metal masters, such as lead-space typesetting, cast-lead printing, steel engraving, steel engraving and so on. Lead-space typesetting is to arrange the layout with lead-space groups of different sizes. The lead plate is cast into a master plate with molten lead alloy liquid. This method is to first bend the steel wire into the required shape, leave a 10mm edge around it, and fix the periphery with wooden strips. Then pour the molten lead alloy liquid into it, and it becomes a die-cutting blade after cooling. Steel engraving is to first bend the steel strip into a curved closed frame similar to the die cut mark, the joints are welded firmly, and the two sides are ground to a height of about 30mm. Then accurately plan the frame line of the cut figure, file the knife edge according to the line, and finally heat treatment to make a die-cut plate. This kind of die-cutting is difficult to produce and the process is more complicated. Steel plate engraving generally selects a steel plate with a thickness of 25mm that is slightly larger than the print image and text, and the side that needs to be processed is finely ground, and then coated with photosensitive liquid and turned over. Mill out the parts other than the knife edge line required by the graphic, then carve the knife edge, and finally heat treatment. Although this type of die-cutting blade has a high cost, it can be used repeatedly for a long time, and is generally suitable for shaped products with small and complex graphics. At present, lead-air typesetting is often used.
②Wooden base. There are several types of wood base plates, such as plywood, wood board, and zinc wood dowel board. The plywood is generally 9 to 13 layers, and the thickness is 18 to 20 mm. It transfers the design pattern to the plywood, drills holes and slits in the lines, and then embeds the die-cutting knife line and the indentation line to make a die-cutting indentation printing plate. This method has higher die-cutting quality and lighter die-cutting plate, which is shorter than the empty lead row knife plate making room. The wood base is a hard wood board that is directly sawn and used as the base.
Zinc-wood dowel board is a die-cut pattern on a zinc plate to make a negative image, the zinc plate is nailed to the wooden board, and after trimming, it can be installed on the die-cutting machine with a steel knife. Plywood is commonly used for wood base.
What is the production process of die-cut and indented version?
The production of die-cut and indented version, commonly known as row knife. The so-called gang knife refers to the process of combining steel knives, steel wires, and blank lining materials into a die-cut and indentation plate according to the specified requirements. At present, the domestic gang knife operation basically uses two types of blank lining materials: metal hollow lead and plywood.
The plywood is used as a template for the blanking material. The bottom plate must be made first, and the other operations are basically the same.
① Manufacture of the bottom plate. According to the design requirements of the product, a certain method is adopted to draw or draw the outline of the die on the bottom plate, and then through different process treatments, narrow grooves are sawn according to the outline. In the making of the master plate, the drawing of the die outline and the quality of the saw seam are the key to the quality of the printing plate. The production of the master plate was all done manually at first. The accuracy of the die depends entirely on the individual's technical level. You must first draw the die graphics on the board by hand, and then use a wire saw to manually sew along the graphic lines; lasers have appeared. The plate making system, in this system, automates the operation until the last process. During the operation, as long as the parameters of the shape and paper thickness of the product to be die-cut are input into the electronic computer, the electronic computer can control the base plate making system so that the base plate is in accordance with the die graphics. Move automatically under the laser beam.
②Guillotine cutting and forming of steel knife (wire). The guillotine cutting and forming processing of steel knife (wire) refers to the process of cutting die-cutting steel knife and steel wire guillotine into the largest forming line segment according to the design specifications and requirements, and then processing it into the required geometric shape . When the knife shape is formed, the choice of steel knife and steel wire should be paid attention to. The rigid steel knife has high mechanical strength and poor elasticity. Try to use it as a straight line knife and not bend too much; soft steel knife has good elasticity and should be used for bending. Large arc line knife. When selecting steel knife and steel wire, factors such as the thickness of the material to be die-cut and the width of the indentation line should also be considered. The general rule is: the thickness of the die-cut product material is different, the height and thickness of the steel wire should be different, as the thickness of the paper decreases, the height of the steel wire increases, and the thickness decreases.
③ Row of knives. According to the product design specification and shape, after marking the specification sample and checking it with the printed graphics and text, you can start the knife operation. According to the different lining materials used, the operation of the gang knife is slightly different. The technical requirements and process difficulty of the metal empty lead gang knife are generally slightly higher than that of the plywood lining material. When using metal empty lead arranging knives, according to certain technological requirements, the empty lead is used to directly fix the knife shape on the designated position of the molded plate to complete the arranging operation, which is very similar to the typesetting operation in movable type printing. In the metal hollow lead arranging knife, the operator is required to be able to flexibly and correctly use various specifications of the blanking material, and the discharged imprinting plate cannot be loose or threaded during the die cutting process. Especially when sorting various geometric figures, it is necessary to ensure that the graphics are standardized and the tightness is appropriate. When there are multiple images in one version, they must be consistent with each other, and there should be no difference due to the difference of the added empty lead ratio. In addition, after the knives are arranged, the vertical lines of the opposite sides of the printing plate should be equidistant to facilitate clamping and firmness when fixing the knives. In the operation of using plywood to lining the empty material, after the steel knife and steel wire are embedded in the saw seam of the bottom plate, they should be hung on the plane of the bottom plate. The gap should be appropriate and there should be no deformation or twisting during embedding or processing. If the layout is composed of multiple bottom plates, the single bottom plates should be arranged and shaped first, and then arranged and shaped one by one, and finally clamped and fixed uniformly. The longitudinal and transverse lines of the printed plate after arrangement must be at an angle of 90° to each other, and the side lines must be parallel to each other, so that the entire layout can be smooth. In addition, the steel knives and steel wire interfaces should be discharged in suitable positions, and the interface gap should be appropriate, and there should be no overlap or excessive gap due to pressure.