Understand the role and production process of laser engraved ceramic anilox roller-1

Understand the role and production process of laser engraved ceramic anilox roller

Although the anilox roller is only one component of the flexo press, it has a great influence on the design of the pattern. Carton printing does not only produce one carton, but rather produces thousands of boxes that customers expect exactly the same. Although designers have raised cardboard flexo to a level that was previously unimaginable, it is almost impossible to improve image print quality without having enough knowledge of the anilox roll to achieve consistency and efficiency.

The original concept of an anilox roll was simple: a steel drum with a cup-shaped mesh engraved on it was used to transfer a certain amount of ink to the plate. However, if you don't understand the improvement of the peripheral technology of the anilox roller, it is difficult to make the right choice in printing applications. Thirty years ago, the only choice for anilox rolls was the mechanically engraved roll bodies, which were achieved by embossing a roll of a certain shape on the surface of the roll. After the embossing is completed, it is customary to apply a layer of hard chrome on the surface. Such mesh shapes generally have a quadrangular pyramid shape and a quadrangular pyramid shape.

 

  

The mechanically engraved anilox roll wears quickly, although the surface is plated with a hard chrome layer. Wear will cause the amount of ink to drop quickly. In addition, the inability to produce finer embossing dies has also created a limit on the number of mesh lines. Most mechanically engraved anilox rolls cannot exceed 500 lines. In today's efficient printing shop where reverse scrapers and sealed double scrapers are used, mechanically engraved anilox rolls are virtually unusable. In addition, the typical hardness range of chrome-plated rolls is HV850-950, while the hardness of laser-engraved ceramic anilox rolls ranges from HV1100-1350.

It is important for the designer to understand that different plasma engraving types can significantly affect the ink release performance of the anilox roll. This means that the number of lines and the amount of ink carried by the rollers from different manufacturers are the same, but the actual use effect is not the same. Different ink release rates result in different print densities. In addition, the theoretical volume of the anilox roll and the actual transfer volume are two completely different concepts. The JCTPRINT porosity of the ceramic layer has a large effect on the release of the ink. Different porosities result in different printing densities. The hardness of the ceramic layer determines the stability of the roll life and print density. Volume, porosity, hardness, laser engraving and ceramic spray combination control, each factor affects the final performance of an anilox roll. In a nutshell: Anilox is not a commodity.

Anatomical ceramic anilox roller

First, the substrate is selected, and the original anilox roll substrate is made of seamless steel pipe. Despite being durable, these rollers are heavy and incorrect maintenance can cause corrosion problems. To deal with corrosion problems, thin-walled stainless steel substrates have been introduced to the market. Light weight, these rolls are more expensive. However, it has the advantage of corrosion resistance.

 

  The new technology upgrade is the carbon fiber roll body. On the surface, the carbon fiber roll body is no different from the traditional steel roll body, and the shaft heads are similar. However, the carbon fiber structure of the roller body is 40-60% lighter than the steel roller of the same specification. In addition, its benefits are harder and more stable. The surface is sprayed with the same durable ceramic coating in the same pattern as the traditional laser engraved anilox roll.

The structure of the carbon fiber roll body is first of all a high strength, light weight tube. A high-strength carbon fiber string coated with a high-performance resin is wound around the surface of the mandrel to form a tubular body. Considering the influence of the length of the pipe body, the parameters such as the strength of the carbon fiber rope, the angle of winding, and the thickness of the pipe wall should be determined according to the specifications of the customer. After winding, it solidifies at a high temperature. This produces a rigid, lightweight composite tube.

The shaft head is the next step. Various materials can be used, including carbon fiber, carbon steel, stainless steel, aluminum, and the like. The composite joint is realized by pressure welding the shaft head to the pipe end by a high-strength epoxy resin. This method requires the shaft head to be completely inserted into the composite pipe wall.

 

 

Producing a ceramic layer

 The hard ceramic layer on the surface of the anilox roll is produced by a plasma gun. The name is derived from a gas plasma or a pear gas that produces a ceramic layer. The nozzle consists of an anode and a cathode, and the two poles are connected to a high voltage to generate an electric arc. The working gas flows through the high voltage arc and is ionized, and the energy generated causes the gas to expand under high pressure. The high pressure gas escapes to the nozzle opening to form a bundle of thermally expanded plasma high velocity flame streams. The chromium oxide coating powder is sprayed into the spray gun and passed through the arc. The temperature of the plasma flame is close to 30,000 ° C, and the chromium oxide powder is melted through the flame core and deposited on the surface of the roller body that is rotated before the spray gun. The thickness of the coating is determined by the rotational speed of the roller and the speed at which the gun moves. The ceramic layer provides corrosion resistance and wear resistance to the anilox roll. The coating composition and powder particle size affect the wear resistance of the coating, and the selection of ceramic particles with small particle size and high internal bonding strength is beneficial to improve the resistance of the coating. Grinding performance

 

Of course, the roller body is also laser engraved. This means that the ceramic layer is capable of withstanding the laser engraving process while maintaining its properties and surface integrity. The bond strength between the coating and the surface of the roll must exceed 5000 psi, which guarantees that it will not fall off under the most demanding conditions.