Principles And Advantages Of Laser Engraving

Principles and advantages of laser engraving

Direct laser engraving is a fully integrated, two-step, filmless platemaking process that represents a major milestone for the label printing industry. The pre-press process is by far the most cumbersome link in the entire printing process. Direct laser engraving technology greatly simplifies the pre-press process and greatly improves the efficiency of this process. This also enables printers to respond quickly to the market and provide faster service. What's more, this fast plate making process can be suitable for flexographic, rotary screen printing, letterpress and waterless offset printing.

The basic principle of direct laser engraving

The laser engraving process is a sleeve printing plate imaging process. The printing plate is wrapped around a steel cylinder body and then spun at very high speeds (up to 2400rpm). While the cylinder rotates at high speed, it moves along the horizontal axis and passes through the laser engraving device, exposing the entire plate to a high-intensity CO2 laser beam. The printing plate absorbs the energy of the laser beam causing thermal decomposition of the printing plate material in the engraved area. After engraving the plate is ready for printing after a quick rinse.

Professional 3D software enables operators to easily control the dot formation to ensure high accuracy of the graphic area, including the gradient of dot formation, the height of relief and the size of the bottom of the dot.

This platemaking process is suitable for a variety of materials, including polymers, EPDM (EPDM (including dicyclopentadiene)) rubber sleeves, and photosensitive emulsions for electroformed nickel mesh drums.

In the plate making process of flexographic printing, letterpress printing and waterless offset printing, the non-graphic area is ablated by the laser beam, while the graphic area is completely preserved. In the production of rotary screen printing plates, the material in the graphic area is ablated to form openings in the mesh. This is also the basis for ensuring good ink transfer during the printing process.

Advantages of direct laser engraving

Direct laser engraving has the following advantages:

High production efficiency - the direct laser engraving process is greatly simplified, and the time required is only half of the traditional engraving and plate making process. Plate making for repeat orders only requires uploading files - so the entire preparation process is only a matter of minutes.

Excellent plate quality - perfect plate size means optimum ink transfer and high contrast for fine line art. So small barcodes and text don't need to be resized for clarity and scannability. Embossed bases allow for less dot gain in highlighted areas. Unsupported dots are also dimensionally stable through prolonged wear. The dot relief design prevents dust from accumulating in non-graphic areas.

The quality of the printing plate is more stable - the two printing plate sleeves made before and after can be made to be exactly the same.

Longer life - no plate swell/de-swell. Seamless printing plates are also possible.

Lower cost of plate making - no development and long-term drying, the only cost consumed is the energy consumption of the system operation, a very small amount of CO2 gas and the cost of the printing plate sleeve itself. The compact structure of the system means more space can be saved.

Good environmental performance - Again, no chemicals and UV light are used throughout the plate making process, only a small amount of water and CO2 are used. This means that no emissions-limiting waste is produced.

Quality advantage

At present, there are a series of engraving devices on the market - wide-format engraving machines are mainly aimed at the flexographic plate field, catering to the needs of wide-format and narrow-format suppliers. The professional narrow-web engraving system can be used for the production of printing plates such as flexo, letterpress, waterless offset and rotary screen printing, providing a complete solution for all kinds of prepress production. Professional rotary screen devices are a good choice for large format users.

In general, printers can fully control the printing plate production process, keep costs within a reasonable range, and ensure the perfect quality and stability of printing plates. With the greatly shortened pre-press production cycle, printers can more flexibly respond to market challenges, because now the length of the industry's lead time has become the main means of competition.