[Die-cutting methods of die-cutting machines] Principles and advantages and disadvantages of flat-bed, rotary, and flat-to-die cutting methods

Die-cutting machines come in different types based on various classification criteria. When classified according to the imprinting method, there are mainly three types: rotary, flat-to-flat, and flat-to-die cutting machines. So, which type of die-cutting machine is good? This article will introduce the principles, advantages, and disadvantages of the flat-to-flat, rotary, and flat-to-die cutting methods.

Flat-to-Flat Die Cutting Machine

Principle:

The shape of the die-cutting plate and the cutting mechanism of the flat-to-flat die cutting machine are both flat. The die-cutting plate is fixed on a flat bed, and the material to be processed is placed on the pressure plate during operation. The die-cutting bed remains stationary while the pressure plate moves back and forth through the crankshaft and connecting rod mechanism, continuously exerting pressure on the die-cutting plate. Each press completes one die-cutting cycle.

Common types of flat-to-flat die cutting machines include vertical die cutting machines and horizontal die cutting machines. Currently, vertical die cutting machines are mainly modified from flat-to-flat imprinting machines, while horizontal die cutting machines have structures similar to single-color offset printing machines, including feeding, die-cutting, and discharging devices, some of which also have automatic cleaning equipment.

Advantages and disadvantages:

Flat-to-flat die cutting machines have a series of advantages such as simple structure, easy operation and maintenance, easy and quick change of die-cutting forms, suitability for different materials and accurate die-cutting. Therefore, they have a wide market demand. However, they also have some drawbacks, for example, they require high pressure during operation, resulting in high labor intensity and low production efficiency. They are widely used in the folding paper industry, sticker industry, and die-cutting and creasing of corrugated cardboard, making them one of the most common die-cutting machines currently used in China.

rotary die cutting machine

Principle:

The die-cutting plate and the pressure mechanism (pressure roller) of the rotary die cutting machine have similar shapes, both resembling cylinders. The die-cutting principle is similar to flexographic printing machines. One or two half-shaped die-cutting forms or magnetic dies with the same curvature as the die-cutting plate are fixed on the die-cutting cylinder. A layer of protective plastic with die-cutting knives on the surface is added to the pressure roller. As die-cutting progresses, the surface layer of the protective plastic is destroyed, and it needs to be removed and replaced with a new layer at regular intervals. During die-cutting, the material to be processed is fed between the die-cutting cylinder and the pressure roller, which come into contact to complete the die-cutting task as they rotate.

Advantages and disadvantages:

Since the rotary die cutting machine operates with the continuous rotation of the pressure roller, its efficiency is relatively high compared to other die-cutting machines, making it particularly suitable for large-scale production. However, because of the high die-cutting speed, sometimes it cannot achieve the required die-cutting precision. Similar to the flat-to-flat die cutting machine, it uses the principle of line contact to complete the die-cutting operation, so it requires relatively small pressure, and the pressure distribution is more uniform, resulting in smoother machine operation. However, the die-cutting knives are curved on the rotary die cutting machine, which makes plate-making and installation more complicated, with higher technical difficulty and higher plate-making costs. The cost of die-cutting forms required by the rotary die cutting equipment is 25%-100% higher than that of the flat-to-flat die cutting forms.

Flat-to-Die Cutting Machine

Principle:

The flat-to-die cutting machine works based on the principle that the die-cutting plate is fixed on a flat bed, and the bed can move back and forth with the help of a back slide. During operation, the material to be processed passes through the die-cutting cylinder for die-cutting. As the die-cutting cylinder rotates, the bed moves forward to complete the die-cutting and moves back to the starting position before the next piece of paper is fed. At this moment, the bed does not come into contact with the working surface of the die-cutting cylinder.

Advantages and disadvantages:

This equipment uses a flat bed instead of a pressure roller, so during operation, the contact between the die-cutting plate and the die-cutting cylinder is in a line shape rather than face-to-face. Therefore, the machine requires relatively low pressure during die-cutting, resulting in more stable machine operations. However, the forces generated during the interaction between the die-cutting plate and the die-cutting cylinder can cause deformation and displacement of the cutting line, which restricts its application range. It is generally only suitable for die-cutting paperboard with a weight of less than 400g/m2, making it particularly suitable for paper die-cutting, electrochemical stencil punching, and hot foil stamping. During paper die-cutting, attention should be paid to the fiber direction of the paper, and it should be parallel to the axial direction of the die-cutting cylinder to avoid severe paper stretching and shrinking.