Color Laser Marking
Using a newly developed laser marking technique, it is possible to apply marking in various colors on plastic surfaces. The process is suitable for use with film, painted surfaces and transparent parts as well.
Applying color markings on plastic surfaces by means of laser printing has to date been possible for only a few colors and entailed a great deal of effort. Instead, color identification of plastic parts has relied primarily on gravure or ink-jet printing methods. DSP-Print-Tec GmbH has now developed a new printing technique with which a standard industrial laser can mark plastic surfaces in color.
The underlying principle employs a pigment-containing carrier material that the laser melts and bonds to the surface. This carrier material is based on a thermoplastic or other material that melts. The material is applied to the surface to be marked as a thin layer of powder. The thermal energy of the laser melts the powder in the area being marked. This bonds some of the pigment contained in the powder to the product surface. Power particles that are not bonded by the laser are vacuumed off and cleaned with the aid of several filters. The powder is reclaimed from the air so that it can be reused. Reclaiming the unused powder reduces the costs versus other printing methods.
The process is a non-contact one and the marking dries in a very short period of time. The amount of powder applied determines the intensity/contrast of the marking. The relatively low laser output needed ensures that the product surface being marked of treated gently. Depending on the carrier material in which the pigments are embedded, the process is suitable for use with very many plastics and can also be used for film, painted surfaces and transparent parts.