Unveiling the Power of Precision: UV Laser Marking Machines Explained

Fiber laser marking machines offer a huge leap forward in product and part marking.  This process has traditionally been carried out using many other means. Adhesive polymer labels, direct part marking via indelible pen, or the ink-printing of standard forms such as barcodes are used. None of these methods are considered to be particularly permanent, and they can all be removed with varying degrees of effort.

The power of laser light has opened up a whole new method of marking products, and in doing so has introduced a much more robust process.  Fiber laser marking has given industry a powerful, flexible method of doing this.  increasingly cost-effective means of permanently marking any product or even packaging solution. You can find out more here.

Many industrial applications rely on IR lasers to do the work, but these may not be appropriate for some applications.  This is particular to the marking of PCB equipment, and the etching of lightweight polymer materials.  In these cases, it becomes much more appropriate to use an Ultra-violet (UV) laser instead.  

UV lasers, which are used in the industrial field of cold processing, are not primarily “heat” treatments, unlike infrared lasers. Moreover, ultraviolet light is typically easier to be taken in by most materials than infrared light is. Many non-metallic materials can benefit from this “cold” photo-etching process. High-energy ultraviolet photons disrupt chemical bonds on the exterior of the substance. This results in rounded edges and minimum carbonization.

When dealing with light-weight materials, UV lasers have a much more focused output, and do not generate the heat that is typical of IR lasers. The UV laser works in a very similar way to the IR laser, except for one crucial step which ensures that the delivered beam is of the right wavelength.

When the laser diode generates photons from input electricity and delivers them to the fiber optic cable. The core is usually made of silica glass and helps to focus, while the cladding is a restrictive layer. In nature, light follows the inverse square law and will travel in all possible directions. There are two main parts to a fiber-optic cable that work together to concentrate light and create a laser beam: the fiber core and the cladding. The cladding is opaque and is made to reflect light back into the core, where it can’t escape. This means that all the focused light is directed towards the output end of the fiber. A lens fitted at the end of the system focuses the light.

Once the light enters a section known as the laser cavity, it is collected. There, it is amplified to produce an intense beam that is capable of marking even the toughest metals. This section of the fiber has two additions that help the amplification.  First, it is the main area that is ‘doped’ with rare earth metals.  These help focus and intensify the light.  Secondly, the area has a special device known as a Fiber Bragg Grating, which is used to bounce the photons back and forth.  In this way, as more photons join those being jostled, the light is amplified, and the laser beam made more intense.

The laser cavity’s doping element determines the wavelength emitted by the doped fiber. This means that any photons emitted from the laser cavity will all be of the same frequency. This is why different varieties of fiber lasers produce light of narrowly defined wavelengths, and colors.  The intensity of the laser light’s electromagnetic energy is proportional to the wavelength. This is dependent upon the type of fiber laser. 

UV fiber laser equipment has a much shorter wavelength than regular fiber lasers, at around 355 nm.  This makes them far more precise in terms of their beam. Either a red laser’s power can be doubled or an infrared laser’s power can be tripled to produce an ultraviolet emission. By tripling the laser’s emission wavelength transforms an infrared laser into one that can produce ultraviolet light.  The IR beam is directed via a crystal system, which modifies the wavelength directly, producing UV light as a result. This UV light can be focused to produce a light spot.

Either a red laser’s power can be doubled or an infrared laser’s power can be tripled to produce an ultraviolet emission.   The IR beam is directed via a crystal system, which modifies the wavelength directly, producing UV light as a result.

With the UV laser beam developed within the optical fiber, it can be transported to the tip of the laser, and can do the work required. This outlet end may have a range of different lenses attached, to deliver the beam in the way required.  Laser etching may require a more focused beam, so that the energy digs into the material, while marking may not require such intensity.

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