ABSTRACT
Using a laser to mark or code information on a product-laser marking-is one of the most common industrial applications of lasers [1,2]. Laser marking often takes the form of an alphanumeric code imprinted on the label or on the surface of the product to describe date of manufacture, best-before, serial number or part number but the mark can also be a machine-readable bar code or 2D symbol (ID matrix) [3]. This type of marking is often specified as laser coding. Since the equipment used for surface processing of a macroscopic nature (e.g. scribing, melting, smoothing or roughening, annealing, etc) is basically the same equipment sold for laser marking, the term laser marking has taken a more general meaning than simple coding. Hence, as well as coding, laser marking also includes functional marking (such as scribing gradation lines on a syringe) or decorative marking (such as engraving a logo or graphic image on an integrated circuit).
