Introduction to the overall process and knowledge of die-cutting indentation

Die-cutting indentation is a special process in post-press processing, mainly according to the design requirements to consider whether the application. This paper mainly from the definition of die-cutting indentation, die-cutting indentation printing plate and die-cutting indentation production process of several aspects, a rough introduction to the overall process of die-cutting indentation.

01. Die-cutting indentation
The die-cutting and indentation process is to make the edge of the color printed matter into various shapes according to the design requirements, or to add special artistic effects on the printed matter to achieve a certain use function. The process of punching the substrate into a certain shape on a die cutting machine with a steel knife (or engraving it with a steel plate) is called die cutting process. The process of using steel wire to press out traces on the substrate or leave groove marks conducive to bending is called indentation process.

02. Die-cutting indentation plate
The printing plate used for die cutting is actually a steel wire with a front opening, and its height is about 23.8mm. The steel wire is bent into various required shapes on the fixture and then arranged 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, which is slightly lower (about 0.8mm lower) than the knife line used for die cutting. After being arranged into a "printing plate", it is imprinted with it to make traces appear on the surface of the substrate. Seamless tools with special requirements are made of one piece of steel. The cost of this tool is higher, but it is durable.

03. What are the bottom plates of die-cutting indentation printing plates?
When making die-cutting and indentation printing plates, the bottom plate should be made first, and then the net wire should be bent according to the required knife type and discharged into the bottom plate. The bottom plate has two kinds of metal bottom plate and wood bottom plate.

① Metal bottom plate.

There are many kinds of metal bottom plates, such as lead blank typesetting, cast lead version, steel type engraving, steel plate engraving, etc. Lead-empty typesetting is a layout with groups of lead holes of different sizes. Pouring the lead plate is made of molten lead alloy liquid. This method is to first bend the steel wire into the required shape, leaving a 10mm edge around it, and fixing the periphery with wooden strips.

The molten lead alloy liquid is then poured in and cooled to become a die-cutting knife plate. The steel engraving plate is to bend the steel strip into a curved closed frame similar to the die cutting mark, the joint is welded firmly, and both sides are ground to a height of about 30mm. Then accurately planed the frame line of the cut figure, filed the knife edge according to the line, and finally heat treated to make a die-cutting plate. This die-cutting production is difficult and the process is more complex.

The steel plate engraving is generally made of a steel plate slightly larger than the printed picture and text and with a thickness of 25mm. The side to be processed is finely ground, then photosensitive liquid is coated and dried. Mill the parts other than the knife edge line required by the picture and text, then carve out the knife edge, and finally heat treat. Although the cost of this die-cutting knife version is very high, it can be used repeatedly for a long time and is generally suitable for small and complex shaped products. At present, lead-empty typesetting is used more often.

② Board bottom plate.

There are several kinds of plywood, wood board, zinc wood nail board and so on. Plywood is generally 9~13 layers, the thickness of 18~20mm. It is to transfer the design pattern to the plywood, drill holes and saw seams at the lines, and then insert the die-cutting knife line and indentation line to make the die-cutting indentation printing plate.

The quality of this method is higher, and the weight of the die-cutting plate is light, which is shorter than that of the empty lead knife plate making room. The board bottom plate is the hard board directly sawn as the bottom plate. The zinc-wood nail plate is to make the die-cutting pattern on the zinc plate into a negative figure, nail the zinc plate to the wood plate, and install the steel knife on the die-cutting machine after trimming. plywood is commonly used in the bottom of the board.

04. What is the production process of die cutting and indentation?
Die-cutting indentation version of the production, commonly known as row knife. The so-called row of knives refers to the process operation of combining steel knives, steel wires and lining materials into die-cutting indentation plates according to the specified requirements. At present, the domestic row of knives basically uses two kinds of lining materials, metal empty lead and plywood.

The plywood plate is used as a template for lining empty materials. First, the bottom plate must be made. Other operations are basically the same.

① Fabrication of base plate.

It refers to the design requirements of the product, using a certain way, drawing or drawing the outline of the die on the bottom plate, and then sawing out the narrow groove according to the contour line through different process treatment. In the production of the bottom plate, the drawing of the outline of the die and the advantages and disadvantages of the saw seam are the keys to the quality of the printing plate.

At first, the production of the bottom plate was all done manually. The accuracy of the die depends entirely on one's technical level. First, one must draw the die figure on the board by hand and then manually saw the seam along the figure line with a wire saw. At present, a laser plate making system has appeared. In this system, the automatic operation is carried out until the last process. In the operation, only the parameters such as the external dimension and paper thickness of the product to be die cut are input into the electronic computer, the electronic computer can control the base plate production system, so that the base plate in accordance with the pattern of the die automatically move under the laser beam.

② Cutting and forming of steel knife (wire).

The cutting and forming of the steel knife (wire) refers to the process of cutting the steel knife and wire 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 type is formed, the choice of steel knife and steel wire should be paid great attention to. The rigid steel knife has high mechanical strength and poor elasticity. It should be used as a straight line knife as much as possible and should not be bent too much. Soft steel knife, good elasticity, should be used as a curved line knife as much as possible.

When selecting steel knives and steel wires, factors such as the thickness of the material of the die-cut product and the width of the indentation line should also be considered. The general rule is that the thickness of the material of the die-cutting product is different, and the height and thickness of the steel wire should be different. With the decrease of the thickness of the paper, the height of the steel wire increases and the thickness decreases.

③ Rank of knives.

According to the product design specifications and modeling, after the specification sample is drawn and checked with the printed picture and text, the knife arrangement operation can be started. According to the different lining materials used, the knife arrangement operation is slightly different. The technical requirements and process difficulty of metal empty lead knife arrangement are generally slightly higher than those of plywood lining empty materials. When using metal empty lead knife, according to certain technological requirements, the knife type is directly fixed at the designated position of the molded plate with empty lead to complete the knife arrangement operation, which is very similar to the typesetting operation in movable type printing.

In the metal empty lead cutter, the operator is required to be flexible and free to correctly use various specifications of lining materials, and the discharged stamping plate cannot be loosened or strung in die cutting. Especially in the arrangement of various types of geometry, it is necessary to ensure that the graphics specification, but also to ensure that the tightness is appropriate. When there are multiple maps in one edition, they should be consistent with each other, and there should be no difference due to the different lead ratios added.

In addition, the vertical line of each point on the opposite side of the printing plate should be equidistant after the knife is arranged, so as to facilitate the clamping and fixing of the knife. In the operation of using plywood lining empty material to arrange knives, steel knives and steel wires shall be vertically hung with the plane of the bottom plate after being embedded in the saw seam of the bottom plate, with appropriate clearance, and no deformation or twisting shall occur during embedding or processing. If the layout is composed of multiple base plates, the individual base plates should be arranged and shaped first, then arranged and shaped one by one, and finally clamped and fixed in a unified way.

After the printing plate is arranged, its longitudinal and transverse lines should form an angle of 90 ° with each other, and each side line should be parallel to each other, so that the whole layout can be smooth. In addition, the steel knife and steel wire interface should be discharged in the appropriate position, and the interface gap should be appropriate, and the phenomenon of overlap or excessive gap should not occur due to pressure.

④ Check and check and fix the knife.

Some solid knives are also called printing plates or card plates, that is, the arranged printing plates are loaded and stuck in the plate frame. After the knife arrangement is completed, do a comprehensive inspection again, and only after the verification is correct can the knife fixation be officially started. For printing plate fixing knives with empty lead lining materials, wooden strips shall be added around the plate frame, and then fixed directly with a plate fixing lock. For die-cutting plates with plywood lining empty materials, wooden strips shall be added according to the specific conditions of the whole layout, and then fastened firmly by the plate fixing lock clamp.