Laser ablation systems
Source: CAN Newsletter December 2006
Cleaning with laser radiation means gently removing contamination and coating layers with bundled light. A powerful focused laser beam (such as from a Nd:YAG or CO2 laser) strikes the surface for some thousand billionth of a second. The surface absorbs most of the power. The radiation energy of the laser beam is directly transformed into thermal energy and removes/vaporizes the contamination. The material is very gently cleaned without damage by the extremely short and locally limited effect of the radiation. As the basic material, unlike the surface layer, does not absorb but rather reflects the laser beam, the cleaning process stops automatically once the container has been removed. Since metallic materials reflects more light than other materials, they are especially suitable for laser beam cleaning. Thus plates and sleeves used in printing applications are suitable objects for laser ablation.
Embedded in an innovative laser ablation system designed for such printing plates and sleeves are the latest servo drives with CANopen interface. The drives and motors ensure that the system functions accurately, with high quality tone screens up to 175 lines per inch, high definition positive and negative detail and text less than two points in size. The laser ablation system was manufactured in the UK and is the first machine of its kind in the world capable of handling printing plates and sleeves up to 3 m in length, for use in flexo, dry-offset and letterpress printing, according to the company.
