Materials Digital Library

  • Acrylics (11)

    Acrylics are cut by "vaporisation". The absorbed laser radiation initiates a process which comes close to a physical phase change from solid to liquid to vapour with a remarkably low level of chemical degradation. The vapour, colourless with a distinctive smell, is highly inflammable and burns with a sooty flame. A gentle stream of pressurized air or nitrogen blows the vapour away from the cutting zone to prevent its ignition. It also dries the remaining liquid melt on the cut edge, creating a glossy, smooth, flame-polished like cutting edge. Should the flow of air be too forceful, the solidifying layer becomes disturbed and the cut edge gets a "frosted" appearance. Due to the amount of filler added to the acrylics to change their appearance from transparent to coloured, the cutting process changes and the cut edge loses its glossy appearance. Because the fumes generated by the laser are highly inflammable, the system must never be left unattended while acrylics are being cut.
     

  • Membrane Switches (8)

    Membrane switches are mostly made of different types of thin thermoset plastic. Its laser cutting process is done by melt shearing and chemical degradation. The more the molecules join together in a three-dimensional matrix instead of forming linear chains, the more chemical work has to be done to break the structure and the molecules in addition to the physical phase change of the melting process. Moreover, the melting point of many thermoset plastics is close to the degradation temperature. The unfortunate result is that the cut edge of many plastics shows a yellowish discoloration. This can, however, be reduced by applying compressed air as assist gas. Nevertheless, the thinner the foil the better the cut edge quality.
     

  • Industrial Textiles (9)

    The non-contact process of laser cutting results in no tool wear, eliminating the downtime for changing or resharpening of tools required by traditional blade or knife cutting. Laser cutting offers a high degree of precision, consistency, control, and flexibility needed in the textile industry for cutting industrial filters, airbags, tarpaulins, luggage and leather goods, footwear, automotivs goods, woven or non-woven (synthetic) fabrics. Laser cutting of synthetic woven or fibrous materials also carry the advantage of sealed (welded) or smooth-edge finishes, which do not demonstrate the fraying typical of cutting by mechanical means. Layers can be welded as well and parameter settings coordinate process speed and weld strength. Diffuse gas assist can prevent discoloration and charring of cut edges for most materials. Different sizes and grades of automation offer solutions which can be tailored to meet specific customer needs, and integrated into existing production environments.
     

  • Paper and Cardboard (2)

    Though the cutting of paper or cardboard is a thermal combustion process, discoloration of the cutting edge is hardly visible. The precise adjustable laser power makes it possible to engrave even on paper, making use of the discoloration by controlled burn. Paper, cardboard or corrugated board can be engraved and cut in the same way.
     

  • Wood (13)

    The absorbed laser power is used to break the chemical bonds and crack up the cellulose molecules to their constituents (cutting by chemical degradation), generating a carbon based smoke and water vapour. The top and bottom surface of the workpiece retain unchanged whereas the cut edge is covered with a layer of residual carbon dust, which blackens the cut edge. The darkening of the cut edge depends highly on the density of wood, applying a high pressured air jet blows the loose carbon dust off and minimizes the discoloration of the cut edge. Cutting speed and quality may change due to varied density in batches of wood or diverse water content from piece to piece or even in one piece (knots). Changes in density may prevent the laser from burning through. Plywood is far more homogeneous than "natural" wood and the cutting process more reliable and constant. Plywood with thermally unfriendly glues (phenolic based glues) and wood with a high content of resin are undesirable for laser processing. (Laser grade plywood is available from most suppliers).