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High Contrast and intact Surface - a Challenge in Laser Marking of Plastics

Laser Marking has become a widely accepted technique to label a large variety of materials from hard carbide ceramics over packaged microelectronic devices and a variety of metals to coated cardboard boxes, traditionally using lasers with high power and good overall efficiency, such as CO2 and Nd:YAG lasers. Most of the materials being marked, in particular organic substances like plastics and varnishes undergo a more or less pronounced burning or ablation of the surface which leads to a relief structure. We have developed a method to mark plastic materials which contain some particulate filler (pigment, dye or additive) using laser pulses of shorter wavelength than most of the known processes, which therefore are not absorbed by the matrix material.