Functional Principle

General

Laser light is marked of the characteristic wavelength of the used laser type and of a hight power density. For marking the laser beam is focused on the material. The interaction with the surface causes a change of the material as change in color, engraving or removal of material.

This changes depends mainly on the wavelength of the laser and on the power density of the laser beam in the focus. The power density is the sum of laser power and focal diameter.

Different laser types are described of their wavelength and output power of the produced laser beam.

For a successful marking, the material has to absorbe laser light with a special wavelength and the material has to be changed thereby.

Types of Marking
Engraving Metals, Ceramics, Plastics
Tempering Tarnish Metals
Removal Covered Materials
Change in Color, Bleaching Plastics
Foaming Plastics

Principle

The laser rod and the pump source (laser lamp) are placed in the pumping unit, where the source will pump energy in the laser rod. There the laser light is produced, that will be refelcted between two mirrors. Because of the reflection through the laser rod, the laser light is amplified. The back mirror reflects the light completely (100%-mirror) and the front mirror only about 70%. The rest will pass this mirror and is for use of marking. The outputed beam from the resonator will be expanded and then deflected by the mirrors in the scanning head. With a special objektive the laser beam will be focussed on the marking field. Dependent on the choose of the objective, a marking field is produced p.e. of 115×115 mm.

If the marking field is not sufficient, there is the possibility of a greater objective or moving of the material, that should be marked, with external units as p.e. axles.

With an acusto-optical chrystal ( Q-Switch ) the laser beam can be switched on and off very fast or pulsed. Therefore short laser pulses will be produced with high power peaks. The adjustable pulse frequency depends strongly on the material and is to adjust, depending on the laser type, between 0 and 100 kHz.

The Run-up of the laser system and the monitoring is done by a PLC-Control of SIEMENS ( S5AG95 oder S7-300).

The marking ist controled by a PC-Control Board ( RTC-Karte ). This Control Boards owns a processor and can together with integrated hardware functions ( SHT-Interface) work off a marking order autarchic. The marking data has to be programmed in the user system of the PC

Options as Cover Marking, Stepping Motors, external Order Control, Networking to other PC-Systems a.s.o. are possible.

Laser Rod

The laser rod is a artificial cultivated chrystal of Yttrium-Aluminium-Granat (YAG) or Yttrium-Vanadium-Oxid (Vanadat), in which a small part of the Yttrium-Ions are replaced of Ions of the element Neodym (Nd), the laser active material. It is almost transparent and shimmers light pink. The dimension of the laser rod depends on the specification of the laser. A typical diameter is about 4 mm.