Plastics Decorating - January/February 2008 - (Page 30) TECHNOLOGY FEATURE continued from page 29 The output mode of the laser beam is critical to the marking performance. Lasers can be supplied by manufacturers as multi-mode, TEM00 (transverse electromagnetic mode) or anything in between, including low-order mode. These output modes relate to factors including the beam divergence and power distribution across the diameter of the laser beam. Loworder and TEM00-mode lasers are particularly well-suited for high-speed vector marking of Data Matrix and Barcodes, single-stroke alphanumerics, filled true-type fonts, and complex graphics because of their ability to achieve a small focused spot resulting in a very narrow line with well-defined edges. Power density is a function of focused laser spot size. Focused laser spot size for any given focal length lens and laser wavelength is a function of laser beam divergence, which is controlled by laser configuration, mode selecting aperture size, and upcollimator (beam expander) magnification. Pulse repetition rate (via acousto-optic Q-switch) and peak power density are critical parameters in forming the mark and achieving the optimal contrast and speed. High peak power at low frequency increases the surface temperature rapidly, vaporizing the material while conducting minimal heat into the substrate. As the pulse repetition increases, a lower peak power produces minimal vaporization but conducts more heat. Beam velocity (speed) also is a critical factor. The use of laser additives will enhance and optimize the machine vision code contrast and decrease marking cycle times. These factors ultimately save money and increase manufacturing production. Material science solutions are cost effective, easy-to-use, and possess no deleterious effects on the polymer products’ physical and chemical properties given the proper formulation. Applications An excellent application example is 2D Data Matrix codes applied via laser to harsh environment underhood automotive fuel components and assemblies (typically Acetals, Nylons, and Polyesters). As shown in Example A, page 32, the ⅛" size code is marked in about 200 milliseconds. Data contained in the code includes full traceability of the component part (from resin batch, mold-machine, date-shift-time, and assembly leak test). New technology advancements for laser marking of Acetals further expands the realms of product serialization and traceability. Example B: As explained by one automotive executive, “Many of the underhood Acetal fuel components we continued on page 32 Your Source for Decorating and Automation Solutions As your one-stop for state-of-the-art decorating machinery and automation systems, Versadec Corporation combines close to 100 years of manufacturing expertise from its companies - Screen Tech and Acromark. Specializing in building machines for screenprinting and hot stamping, we offer comprehensive, in-house capabilities to fulfill your most challenging decorating and assembly projects. To ensure the highest quality products, we maintain close relationships with suppliers of inks, foils, transfers, dies, and tooling used in our decorating equipment. Founded on an industry guarantee of total satisfaction, allow us to be your true turnkey solution for decoration and automation machinery. 1 ton, 2 1/2 ton hot stampers, and semi automatic silk screeners IN STOCK NOW. For details on our equipment visit our new website WWW.VERSADEC.COM 30 http://www.versadec.com http://www.versadec.com
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