PRINCIPLE OF A CO2 LASER CODER
CO2 laser marking machines are gas lasers marking machines that are based on carbon dioxide gas mixture. CO2 laser marking machines are ideal for high speed precision marking and provides the best industrial solution for product identification and traceability.
Energy will be releases as a photon (light)
The lasing medium (such as carbon dioxide -CO2), is held within a resonator which also contains a 100% and a partially reflective mirror mounted parallelly at each end. When required the medium is excited by an RF signal causing electrons to absorb this energy causing them to move to an excited state. The atom will return to its ground state and during this transition the initial absorbed energy will be releases as a photon (Light). These photons will travel across the resonator and will be reflected backwards and forwards inside the vacuum.
Built up into a beam and directed onto highly polished mirrors
As the light pass through the lasing medium it causes other excited state electrons to release their energy (Stimulated emission) at the same wavelength and direction thus amplifying the energy within the resonator. The energy will build up into a beam and will overcomes the resistance of the partically reflective mirror and will exit the resonator chamber. The light beam is then directed onto two highly polished mirrors mounted onto very high speed galvo motors. These mirrors are moved to direct the light towards the surface to be coded. Before the light exits the Laser it passes through a lens to concentrate all the energy into a very small spot at a specific distance away from the lens.
This highly focused beam is used to either remove material from the surface (Ablation), burn into a material (Engraving) or cause a chemical change within the material (Photochemical).
The most important consideration is how well the material being coded absorbs the laser beam. This will determine the type of laser used as different wavelengths can have different absorption characteristics.