Converting

Many materials like fabrics, plastic foils, and papers are processed on the fly using a reel to reel process. Applications may be found in the medical and food industry in the manufacturing of pouches for soups, coffee or beverages, but also in digital printing lines or production lines for grinding paper. Lasers are an established tool in these converting lines. Typical applications are cutting (incl. kiss cutting), scoring and drilling. In one example, the material is processed in the direction of travel or in a down web application. In this case, the laser beam is focused on the web by a fixed optic, while the material is moved underneath by web, allowing the material to be slit to width. In another example, the material is processed perpendicular to the material (web) flow direction. This is referred to as a cross web application. A galvanometric scanner steers the laser beam across the material while compensating for the material flow speed by using a velocity sensor. In most cases, a CO2 laser is used emitting a wavelength of 10.6 µm or 10.2 µm (ideal for PP processing), as mainly organic materials and plastics are processed. This wavelength is absorbed with most of the materials very well. In some special instances such as in the medical segment, UV lasers are used.